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Title:
PROTECTED COMPOSITIONS COMPRISING TWO COATING LAYERS
Document Type and Number:
WIPO Patent Application WO/2019/209261
Kind Code:
A1
Abstract:
Composition comprising a core of bioactive agent that is surrounded by first and second coating layers, wherein the composition provides pH dependent release of the bioactive.

Inventors:
FULLING PATRICK DAVID (US)
FISCHER MATTHEW JOSEPH (US)
HUME JOHN ALLEN (US)
Application Number:
PCT/US2018/029023
Publication Date:
October 31, 2019
Filing Date:
April 24, 2018
Export Citation:
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Assignee:
NOVUS INT INC (US)
International Classes:
A61K9/16; A23K20/00; A23K40/30
Domestic Patent References:
WO2007072060A22007-06-28
Foreign References:
US20170216208A12017-08-03
Attorney, Agent or Firm:
BISSEN, Shirley T. et al. (US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A composition comprising (a) an irregularly-shaped core comprising a bioactive agent; (b) a first coating layer surrounding the irregularly-shaped, the first coating layer comprising at least one polymer; and (c) a second coating layer

surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases the bioactive agent in an aqueous medium whose pH is less than about 5.0.

2. The composition of claim 1 , wherein the bioactive agent in the irregularly-shaped core is an amino acid, an amino acid analog, a vitamin, a mineral, an antioxidant, an organic acid, a polyunsaturated fatty acid, an essential oil, an enzyme, a prebiotic, a probiotic, an herb, a pigment, or a pharmaceutically active agent.

3. The composition of claims 1 or 2, wherein the irregularly-shaped core comprises or consists of a salt of lysine, a salt of choline, or a salt of histidine.

4. The composition of any one of claims 1 to 3, wherein the irregularly-shaped core is devoid of binders, fillers, diluents, or combinations thereof.

5. The composition of any one of claims 1 to 4, wherein the irregularly-shaped core has a diameter ranging from about 200 microns to about 3000 microns.

6. The composition of any one of claims 1 to 5, wherein the irregularly-shaped core comprises a plurality of discrete particles of a second bioactive agent adhering to its surface; or the irregularly-shaped core comprises a surface coating

comprising a second bioactive agent and at least one polymer, provided the second bioactive agent differs from the bioactive agent present in the irregularly- shaped core.

7. The composition of any one of claims 1 to 6, wherein the at least one polymer in the first coating layer is a water-soluble cellulose ether, polyacrylate, polyalkylene succinate, polyalkylene oxalate, polyamide, polyarylate, polycarbonate, polycaprolactone, polycyanoacrylate, polydioxane, polydioxanone, polyether ether ketone, polyethylene glycol, polyalkylene oxide, polyethylene terephthalate, polyhydroxyalkanoate, polyhydroxy ester, poly(2-hydroxy-4- methylthiobutanoate), polyimide, polyketal, polylactide, polymethacrylate, polyolefin, polyorthoester, polyphosphazene, polystyrene, polytetramethylene carbonate, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl methyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or

combination thereof.

8. The composition of claim 7, wherein the at least one polymer in the first coating layer is a water-soluble cellulose ether.

9. The composition of claim 8, wherein the first coating layer comprises about 4% to about 10% by weight of the composition.

10. The composition of claim 7, wherein the at least one polymer in the first coating layer is a vinylpyridine styrene co-polymer.

11. The composition of claim 10, wherein the first coating layer further comprises a hydrophobic agent chosen from a long chain fatty acid, a long chain fatty acid ester, a vegetable oil, a wax, or a combination thereof.

12. The composition of claim 11 , wherein the hydrophobic agent is a long chain fatty acid.

13. The composition of any one of claims 10 to 12, wherein the first coating layer comprises about 8% to about 18% by weight of the composition.

14. The composition of any one of claims 8 to 13, wherein the first coating layer

further comprises a polymer of 2-hydroxy-4-methylthiobutanoate.

15. The composition of any one of claims 1 to 13, wherein the at least one pH

responsive polymer in the second coating layer is polyacrylonitrile, poly(acrylic acid), poly(methacrylic acid), poly(benzyl acrylate), poly(butyl acrylate), poly(ethyl acrylate), poly(dialkylamino ethyl acrylate), poly(2-ethylhexyl acrylate),

poly(methyl acrylate), poly(propyl acrylate), poly(phenyl acrylate),

poly(aminoethyl methacrylate), poly(butyl methacrylate), poly(benzyl

methacrylate), poly(2-ethylhexyl methacrylate), poly(glycidyl methacrylate), poly(hydroxybutyl methacrylate), poly(2-hydroxyethyl methacrylate),

poly(hydroxypropyl methacrylate), poly(methyl methacrylate), poly(phenyl methacrylate), poly(2-acrylamido-2-methyl-1 -propanesulfonic acid), poly(maleic acid), poly(maleic anhydride), polystyrene, polyvinyl acetate, poly(N-vinyl acetamide), poly(N-vinyl formamide), polyvinylpyridine, co-polymer thereof, or combination thereof.

16. The composition of claim 15, wherein the at least one pH responsive polymer in the second coating layer is a vinylpyridine styrene co-polymer.

17. The composition of any one of claims 1 to 16, wherein the second coating layer further comprises at least one hydrophobic polymer, at least one hydrophobic agent, or a combination thereof.

18. The composition of claim 17, wherein the at least one hydrophobic polymer is a water-insoluble cellulose ether, poly(alkyl acrylate), poly(alkyl methacrylate), polyamide, polyimide, polybutadiene, polyisoprene, poly(alkylene succinate), polyalkylene terephthalate), polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl ether, polyvinyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or combination thereof; and the hydrophobic agent is a long chain fatty acid, a long chain fatty acid ester, a vegetable oil, a wax, or a combination thereof.

19. The composition of any one of claims 1 to 18, wherein the second coating layer comprises a vinylpyridine styrene co-polymer, a water-insoluble cellulose ether, and a long chain fatty acid.

20. The composition of claim 19, wherein the second coating layer comprises about 5% to about 15% by weight of the composition.

21. The composition of any one of claims 1 to 20, wherein the bioactive agent is lysine sulfate or lysine hydrochloride.

22. The composition of claim 21 , which releases more than about 20% of free lysine in an aqueous medium having a pH of less than about 5.0.

23. The composition of claim 22, wherein more than about 30%, more than about 35%, more than about 40%, or more than about 45% of free lysine is released.

24. A composition comprising (a) a core comprising lysine; (b) a first coating layer surrounding the core, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases more than about 20% of free lysine after rumen passage.

25. The composition of claim 24, wherein the core comprises or consists of lysine hydrochloride or lysine sulfate.

26. The composition of claims 24 or 25, wherein the irregularly-shaped core is devoid of binders, fillers, diluents, or combinations thereof.

27. The composition of any one of claims 24 to 26, wherein the irregularly-shaped core has a diameter ranging from about 200 microns to about 3000 microns.

28. The composition of any one of claims 24 to 27, wherein the irregularly-shaped core comprises a plurality of discrete particles of methionine adhering to its surface; or the irregularly-shaped core comprises a surface coating comprising methionine and at least one polymer.

29. The composition of any one of claims 24 to 28, wherein that at least one polymer in the first coating layer is a water-soluble cellulose ether.

30. The composition of claim 29, wherein the water-soluble cellulose ether is hydroxypropyl methyl cellulose or methyl cellulose.

31. The composition of claims 29 or 30, wherein the first coating layer comprises about 5% to about 8% by weight of the composition.

32. The composition of any one of claims 24 to 28, wherein the at least one polymer in the first coating layer is a vinylpyridine styrene co-polymer, and the first coating layer further comprises a long chain fatty acid.

33. The composition of claim 32, wherein the vinylpyridine styrene co-polymer is poly(2-vinylpyridine-co-styrene), and the long chain fatty acid is stearic acid.

34. The composition of claims 32 or 33, wherein the first coating layer comprises about 10% to about 15% by weight of the composition.

35. The composition of any one of claims 29 to 34, wherein the first coating layer further comprises a polymer of 2-hydroxy-4-methylthiobutanoate.

36. The composition of any one of claims 24 to 35, wherein the at least one pH

responsive polymer in the second coating layer is a vinylpyridine styrene co- polymer.

37. The composition of claim 36, wherein the vinylpyridine styrene co-polymer is poly(2-vinylpyridine-co-styrene).

38. The composition of any one of claims 26 to 37, wherein the second coating layer further comprises at least one hydrophobic polymer, at least one hydrophobic agent, or a combination thereof.

39. The composition of claim 38, wherein the hydrophobic polymer is ethyl cellulose, and the hydrophobic agent is stearic acid.

40. The composition of any one of claims 36 to 39, wherein the second coating layer comprises about 8% to about 12% by weight of the composition.

41. The composition of any one of claims 24 to 40, which release more than about 25%, more than about 30%, more than about 35%, more than about 40%, or more than about 45% of free lysine after rumen passage.

42. A feed premix comprising the composition of any one of claims 1 to 41.

43. A feed composition comprising at least one nutritive agent and the composition of any one of claims 1 to 41.

44. A method for providing a bioactive agent to a subject, the method comprising administering the composition of any one of claims 1 to 41 , the feed premix of claim 42, or the feed composition of claim 43 to the subject.

45. The method of claim 44, wherein the subject is a ruminant.

Description:
PROTECTED COMPOSITIONS COMPRISING TWO COATING LAYERS

FIELD

[0001 ] The present disclosure generally relates to compositions comprising a bioactive agent and two coating layers, wherein the coating layers are useful in the delivery and protection of the bioactive agent.

BACKGROUND

[0002] Supplementing human and animal diets with essential amino acids and/or other bioactive agents improves health and performance. Bioactive agents may be sensitive to degradation, yet need to be provided with a particular release profile. Combining the bioactive in a composition with polymeric coating layers is one way to deliver protected bioactive agents with desired release profiles. Providing amino acids and/or bioactive agents to ruminants, in particular, is challenging because microbes in the rumen may digest and degrade the bioactive agent of interest before it can be absorbed and utilized by the animal. Over the years, various protection approaches have been taken, but with mixed results. For example, lysine salts have been encapsulated with hydrogenated fats/vegetable oils or within a vegetable matrix. Such encapsulated products, however, provide post-rumen release of lysine of less than 20%. What is needed, therefore, are improved means for protecting bioactive agents.

In particular, compositions that provide pH-dependent release provide advantages in the delivery of bioactive agents.

SUMMARY

[0003] Among the various aspects of the present disclosure encompasses a composition comprising (a) an irregularly-shaped core comprising a bioactive agent; (b) a first coating layer surrounding the irregularly-shaped, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases the bioactive agent in an aqueous medium whose pH is less than about 5.0.

[0004] Another aspect of the present disclosure provides a composition comprising (a) a core comprising lysine; (b) a first coating layer surrounding the core, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases more than about 20% of free lysine after rumen passage.

[0005] A further aspect of the present disclosure encompasses methods for providing bioactive agent(s) to a subject. The method comprising administering a composition comprising (a) an irregularly-shaped core comprising a bioactive agent; (b) a first coating layer surrounding the irregularly-shaped, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer.

[0006] Other features and iterations of the disclosure are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1A presents an image of lysine sulfate particles coated with a 7 wt% first coating layer comprising hydroxypropyl methyl cellulose.

[0008] FIG. 1B shows an image of the hydroxypropyl methyl cellulose- coated particles from FIG. 1 A coated with a 9 wt% second coating layer comprising stearic acid, poly(2-vinylpyridine-co-styrene), and ethyl cellulose.

[0009] FIG. 2 illustrates the release of lysine after 18 hours at the indicated pH levels from uncoated lysine sulfate particles and the lysine sulfate particles comprising two coating layers as described in FIG. 1B.

[0010] FIG. 3A presents an image of lysine sulfate particles coated with a 7 wt% first coating layer comprising methyl cellulose. [0011 ] FIG. 3B shows an image of the methyl cellulose-coated particles from FIG. 3A coated with a 9 wt% second coating layer comprising stearic acid, poly(2- vinylpyridine-co-styrene), and ethyl cellulose.

[0012] FIG. 4 documents the release of lysine after 18 hours at the indicated pH levels from uncoated lysine sulfate particles and the lysine sulfate particles comprising two coating layers as described in FIG. 3B.

[0013] FIG. 5A presents an image of lysine hydrochloride particles coated with a 15 wt% first coating layer comprising stearic acid and poly(2-vinylpyridine-co- styrene).

[0014] FIG. 5B shows an image of the first coated particles from FIG. 5A coated with a 10 wt% second coating layer comprising stearic acid, poly(2-vinylpyridine- co-styrene), and ethyl cellulose.

[0015] FIG. 6 illustrates the release of lysine after 18 hours at the indicated pH levels from the lysine HCI particles comprising two coating layers as described in FIG. 5B.

[0016] FIG. 7A shows an image of uncoated lysine hydrochloride.

[0017] FIG. 7B presents an image of lysine hydrochloride particles coated with a 2 wt% surface coating comprising methionine and methyl cellulose.

[0018] FIG. 7C presents an image of the surface coated particles from FIG. 7B coated with a 15 wt% first coating layer comprising stearic acid and poly(2- vinylpyridine-co-styrene).

[0019] FIG. 7D shows an image of the coated particles from FIG. 7C coated with a 10 wt% top coating layer comprising stearic acid, poly(2-vinylpyridine-co- styrene), and ethyl cellulose.

[0020] FIG. 8 presents the release of lysine after 18 hours at the indicated pH levels from the lysine HCI particles comprising three coating layers as described in FIG. 7D. DETAILED DESCRIPTION

[0021 ] Provided herein are compositions that provide pH-dependent release of bioactive agents. The compositions comprise an irregularly-shaped core comprising a bioactive agent, a first coating layer surrounding the irregularly-shaped, and a second coating layer surrounding the first coating layer, wherein the first coating layer comprises at least one polymer, and the second coating layer comprises at least one pH responsive polymer. The compositions disclosed herein are substantially stable in aqueous media have approximately neutral pH, but release the bioactive agent in aqueous media having pH levels of less than about 5.0. Also provide herein are processes for preparing said compositions and methods of using said compositions for providing bioactive agents to subject in need thereof.

(I) Compositions Comprising Two Coating Layers

[0022] The present disclosure provides a composition comprising a core comprising a bioactive agent and at least two coating layers, wherein the core has an irregular shape, the first coating layer comprises at least one polymer, the second coating layer comprises at least one pH responsive polymer, and the composition releases the bioactive agent in an aqueous medium having a pH of less than about 5.0. a) Core

[0023] The compositions disclosed comprise irregularly-shaped or granular cores comprising a bioactive agent. The irregularly-shaped cores are non-spherical with uneven, rough, or irregular surfaces. See, e.g., FIG. 7A. The irregularly-shaped cores have diameters of at least about 200 microns. In various embodiments the diameter of the irregularly-shaped cores may range from about 200 microns to about 3000 microns, from about 300 microns to about 2500 microns, from about 400 microns to about 2000 microns, or from about 500 microns to about 1500 microns.

[0024] Generally, the irregularly-shaped cores are devoid of binders, fillers, and/or diluents. For example, the bioactive agent is not mixed with one or more binders, fillers, and/or diluents to form uniformly shaped particles. Additionally, particles of bioactive agent are not surface-treated with one or more binders, fillers, and/or diluents to form particles with smooth or uniform surfaces. Non-limiting examples of binders, fillers, and/or diluents include cellulose, microcrystalline cellulose, cellulose ethers (e.g., ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, sodium carboxymethylcellulose, etc.), cellulose esters (e.g., cellulose acetate, cellulose butyrate, and mixtures thereof), starches (e.g., corn starch, rice starch, potato starch, tapioca starch, and the like), hydrolyzed starches, modified starches, pregelatinized starches, phosphated starches, starch-lactose, starch-calcium carbonate, sodium starch glycolate, saccharides (e.g., glucose, fructose, sucrose, lactose, and so forth), sugar alcohols (e.g., xylose, lactitol, mannitol, malitol, sorbitol, xylitol, maltodextrin, trehalose), alginates (e.g., alginic acid, alginate, sodium alginate, and so forth), gums (e.g., gum arabic, guar gum, gellan gum, xanthan gum, and the like), pectins, gelatin, C12-C18 fatty acid alcohols, polyvinylpyrrolidone (also called copovidone), polyethylene oxide, polyethylene glycol, polyvinyl alcohols, waxes (e.g., candelilla wax, carnauba wax, beeswax, and so forth), inorganic materials (e.g., calcium carbonate, calcium sulfate, calcium phosphate, calcium silicate, magnesium carbonate, magnesium oxide, talc, etc.), or combinations thereof.

(i) Bioactive agent

[0025] Each irregularly-shaped core comprises a bioactive agent. The bioactive agent is a biologically relevant molecule. Non-limiting examples of suitable bioactive agents include amino acids, amino acid analogs, vitamins, minerals (/. e. , organic or inorganic), antioxidants, organic acids, polyunsaturated fatty acids, essential oils, enzymes, prebiotics, probiotics, herbal extracts, pigments, and pharmaceutically active agents.

[0026] In some embodiments, the bioactive agent may be an amino acid. Non-limiting suitable amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine, or other known amino acids. The amino acid may be an L-amino acid or a DL-amino acid. The amino acid may be an amino acid free base or an amino acid salt. In some embodiments, the core may comprise lysine. In other embodiments, the core may consist of lysine. In further embodiments, the core may consist of a salt of lysine.

Suitable salts of lyse include lysine sulfate, lysine hydrochloride, lysine acetate, lysine citrate, and lysine dihydrochloride. In a specific embodiment, the core may consist of granular lysine sulfate. In another specific embodiment, the core may consist of granular lysine hydrochloride. In further embodiments, the core may comprise or consist of a salt of histidine. Suitable histidine salts include histidine hydrochloride, histidine bromide, histidine maleate, histidine nitrate, histidine oxalate, and histidine sulfate.

[0027] In other embodiments, the bioactive agent may be an amino acid analog. Suitable amino acid analogs include a-hydroxy analogs, as well side chain protected analogs, N-derivatized amino acids, or amino acid esters.

[0028] In still other embodiments, the bioactive agent may a vitamin. Non- limiting examples of vitamin include vitamin A (retinol), B-complex vitamins (e.g., thiamine, riboflavin, niacin, pantothenic acid, biotin, folate, pyridoxine, choline, cobalamins, etc.), vitamin C (ascorbic acid), vitamin D (calciferol), vitamin E

(tocopherol), and vitamin K (phylloquinone/phytol naphthoquinone). In some

embodiments, the bioactive agents may comprise or consist of a salt of choline.

Suitable salts of choline include choline chloride, choline bicarbonate, choline bitartrate, choline dihydrogen citrate, choline hydroxide, and choline sulfate.

[0029] In yet other embodiments, the bioactive agent may be a mineral.

The mineral may be an organic trace mineral. Suitable organic trace minerals include metal chelates comprising metal ions and amino acid ligands or metal salts comprising metal ions and amino acid or organic acid anions. The metal ions may be selected from the group consisting of zinc ions, copper ions, manganese ions, iron ions, chromium ions, cobalt ions, magnesium ions, calcium ions, and combinations thereof.

Alternatively, the mineral may be an inorganic trace mineral. Suitable inorganic trace minerals include, for example, metal sulfates, metal oxides, metal hydroxides, metal oxychlorides, metal carbonates, and metal halides. By way of non-limiting example, the inorganic trace mineral may be copper sulfate, copper oxide, copper chloride, or copper carbonate. Alternatively, the inorganic trace mineral may be manganese sulfate, manganese chloride, or manganous oxide. In another embodiment, the inorganic trace mineral may be zinc sulfate, zinc oxide, zinc chloride, or zinc carbonate. In yet an additional embodiment, the inorganic trace mineral may be sodium selenite or sodium selenate.

[0030] In alternate embodiments, the bioactive agent may be an

antioxidant. Suitable antioxidants include, but are not limited to, ascorbic acid and its salts, ascorbyl palmitate, ascorbyl stearate, anoxomer, n-acetylcysteine, benzyl isothiocyanate, m-aminobenzoic acid, o-aminobenzoic acid, p-aminobenzoic acid (PABA), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), caffeic acid, canthaxantin, alpha-carotene, beta-carotene, beta-carotene, beta-apo-carotenoic acid, carnosol, carvacrol, catechins, cetyl gallate, chlorogenic acid, citric acid and its salts, clove extract, coffee bean extract, p-coumaric acid, 3,4-dihydroxybenzoic acid, N,N’- diphenyl-p-phenylenediamine (DPPD), dilauryl thiodipropionate, distearyl

thiodipropionate, 2,6-di-tert-butylphenol, dodecyl gallate, edetic acid, ellagic acid, erythorbic acid, sodium erythorbate, esculetin, esculin, 6-ethoxy-1 ,2-dihydro-2,2,4- trimethylquinoline (ethoxyquin), ethyl gallate, ethyl maltol, ethylenediaminetetraacetic acid (EDTA), eucalyptus extract, eugenol, ferulic acid, flavonoids (e.g., catechin, epicatechin, epicatechin gallate, epigallocatechin (EGC), epigallocatechin gallate (EGCG), polyphenol epigallocatechin-3-gallate, flavones (e.g., apigenin, chrysin, luteolin), flavonols (e.g., datiscetin, myricetin, daemfero), flavanones, fraxetin, fumaric acid, gallic acid, gentian extract, gluconic acid, glycine, gum guaiacum, hesperetin, alpha-hydroxybenzyl phosphinic acid, hydroxycinammic acid, hydroxyglutaric acid, hydroquinone, n-hydroxysuccinic acid, hydroxytryrosol, hydroxyurea, rice bran extract, lactic acid and its salts, lecithin, lecithin citrate; R-alpha-lipoic acid, lutein, lycopene, malic acid, maltol, 5-methoxy tryptamine, methyl gallate, monoglyceride citrate;

monoisopropyl citrate; morin, beta-naphthoflavone, nordihydroguaiaretic acid (NDGA), octyl gallate, oxalic acid, palmityl citrate, phenothiazine, phosphatidylcholine, phosphoric acid, phosphates, phytic acid, phytylubichromel, pimento extract, propyl gallate, polyphosphates, quercetin, trans-resveratrol, rosemary extract, rosmarinic acid, sage extract, sesamol, silymarin, sinapic acid, succinic acid, stearyl citrate, syringic acid, tartaric acid, thymol, tocopherols (/.e. , alpha-, beta-, gamma- and delta- tocopherol), tocotrienols (i.e., alpha-, beta-, gamma- and delta-tocotrienols), tyrosol, vanilic acid, 2,6-di-tert-butyl-4-hydroxymethylphenol (i.e., lonox 100), 2,4-(tris-3’,5’-bi- tert-butyl-4’-hydroxybenzyl)-mesitylene (i.e., lonox 330), 2,4,5-trihydroxybutyrophenone, ubiquinone, tertiary butyl hydroquinone (TBHQ), thiodipropionic acid, trihydroxy butyrophenone, tryptamine, tyramine, uric acid, vitamin K and derivatives thereof, vitamin Q10, wheat germ oil, zeaxanthin, or combinations thereof.

[0031 ] In additional embodiments, the bioactive agent may be an organic acid. A variety of organic acids comprised of carboxylic acids are suitable. In one embodiment, the organic acid may contain from about one to about twenty-five carbon atoms. In another embodiment, the organic acid may have from about three to about twenty-two carbon atoms. In a further embodiment, the organic acid may contain from about three to about twelve carbon atoms. In yet another embodiment, the organic acid may contain from about eight to about twelve carbon atoms. In still another

embodiment, the organic acid may contain from about two to about six carbon atoms. Suitable organic acids, by way of non-limiting example, include formic acid, acetic acid, propionic acid, butanoic acid, benzoic acid, lactic acid, malic acid, tartaric acid, mandelic acid, citric acid, fumaric acid, sorbic acid, boric acid, succinic acid, adipic acid, glycolic acid, cinnamaldehyde, and glutaric acid. Alternatively, the organic acid may be comprised of a substituted carboxylic acid. A substituted carboxylic acid generally has the same features as those detailed above for carboxylic acids, but the hydrocarbyl chain has been modified such that it is branched, is part of a ring structure, or contains some other substitution. In one embodiment, the substituted carboxylic acid may contain one or more additional carboxyl groups. Saturated dicarboxylic acids include malonic acid, succinic acid, glutaric acid, and adipic acid, and unsaturated dicarboxylic acids include maleic acid and fumaric acid. In another embodiment, the substituted carboxylic acid may contain one or more hydroxy groups. A substituted carboxylic acid with a hydroxy group on the alpha carbon, i.e., the carbon adjacent to the carboxyl carbon, is generally called a a-hydroxy carboxylic acid. Examples of suitable a-hydroxy carboxylic acids include glycolic acid, lactic acid, malic acid, and tartaric acid. In an alternate embodiment, the substituted carboxylic acid may contain one or more carbonyl groups. Salts of organic acids comprising carboxylic acids are also suitable for certain embodiments. Representative suitable salts include the ammonium, magnesium, calcium, lithium, sodium, potassium, selenium, iron, copper, and zinc salts of organic acids.

[0032] In other embodiments, the bioactive agent may be a

polyunsaturated fatty acid or PUFA. Suitable PUFAs include a long chain fatty acid with at least 18 carbon atoms and at least two carbon-carbon double bonds, generally in the cis-configuration. In an exemplary embodiment, the PUFA is an omega fatty acid. The PUFA may be an omega-3 fatty acid in which the first double bond occurs in the third carbon-carbon bond from the methyl end of the carbon chain (i.e. , opposite the carboxyl acid group). Suitable examples of omega-3 fatty acids include all-cis 7,10,13- hexadecatrienoic acid; all-cis-9,12,15-octadecatrienoic acid (alpha-linolenic acid, ALA); all-cis-6,9,12,15,-octadecatetraenoic acid (stearidonic acid); all-cis-8,11 ,14,17- eicosatetraenoic acid (eicosatetraenoic acid); all-cis-5,8,11 ,14,17-eicosapentaenoic acid (eicosapentaenoic acid, EPA); all-cis-7,10,13,16,19-docosapentaenoic acid

(clupanodonic acid, DPA); all-cis-4,7,10,13,16,19-docosahexaenoic acid

(docosahexaenoic acid, DHA); all-cis-4,7,10,13,16,19-docosahexaenoic acid; and all- cis-6,9, 12, 15, 18,21 -tetracosenoic acid (nisinic acid). In an alternative embodiment, the PUFA may be an omega-6 fatty acid in which the first double bond occurs in the sixth carbon-carbon bond from the methyl end of the carbon chain. Examples of omega-6 fatty acids include all-cis-9,12-octadecadienoic acid (linoleic acid); all-cis-6,9, 12- octadecatrienoic acid (gamma-linolenic acid, GLA); all-cis-11 ,14-eicosadienoic acid (eicosadienoic acid); all-cis-8,11 ,14-eicosatrienoic acid (dihomo-gamma-linolenic acid, DGLA); all-cis-5,8,11 ,14-eicosatetraenoic acid (arachidonic acid, AA); all-cis-13, 16- docosadienoic acid (docosadienoic acid); all-cis-7,10,13,16-docosatetraenoic acid (adrenic acid); and all-cis-4,7,10,13,16-docosapentaenoic acid (docosapentaenoic acid). In yet another alternative embodiment, the PUFA may be an omega-9 fatty acid in which the first double bond occurs in the ninth carbon-carbon bond from the methyl end of the carbon chain, or a conjugated fatty acid, in which at least one pair of double bonds are separated by only one single bond. Suitable examples of omega-9 fatty acids include cis-9-octadecenoic acid (oleic acid); cis-1 1 -eicosenoic acid (eicosenoic acid); all-cis-5,8, 1 1 -eicosatrienoic acid (mead acid); cis-13-docosenoic acid (erucic acid), and cis-15-tetracosenoic acid (nervonic acid). Examples of conjugated fatty acids include 9Z, 1 1 E-octadeca-9, 1 1 -dienoic acid (rumenic acid); 10E, 12Z-octadeca-9, 1 1 - dienoic acid; 8E,10E,12Z-octadecatrienoic acid (a-calendic acid); 8E, 10E,12E- octadecatrienoic acid (b-calendic acid); 8E,10Z, 12E-octadecatrienoic acid (jacaric acid); 9E, 1 1 E, 13Z-octadeca-9, 1 1 , 13-trienoic acid (a-eleostearic acid); 9E, 1 1 E, 13E-octadeca- 9, 1 1 , 13-trienoic acid (b-eleostearic acid); 9Z, 1 1 Z, 13E-octadeca-9, 1 1 ,13-trienoic acid (catalpic acid), and 9E,1 1 Z, 13E-octadeca-9, 1 1 , 13-trienoic acid (punicic acid).

[0033] In yet additional embodiments, the bioactive agent may be an essential oil. Suitable essential oils include, but are not limited to, peppermint oil, cinnamon leaf oil, lemongrass oil, clove oil, castor oil, wintergreen oil, sweet orange, spearmint oil, ceaderwood oil, aldehyde C16, a-terpineol, amyl cinnamic aldehyde, amyl salicylate, anisic aldehyde, benzyl alcohol, benzyl acetate, camphor, capsaicin, cinnamaldehyde, cinnamic alcohol, carvacrol, carveol, citral, citronellal, citronellol, p-cymene, diethyl phthalate, dimethyl salicylate, dipropylene glycol, eucalyptol (cineole), eugenol, iso-eugenol, galaxolide, geraniol, guaiacol, ionone, listea cubea, menthol, menthyl salicylate, methyl anthranilate, methyl ionone, methyl salicylate,

a-phellandrene, pennyroyal oil, perillaldehyde, 1 - or 2-phenyl ethyl alcohol, 1 - or

2-phenyl ethyl propionate, piperonal, piperonyl acetate, piperonyl alcohol, D-pulegone, terpinen-4-ol, terpinyl acetate, 4-tert butylcyclohexyl acetate, thyme oil, thymol, metabolites of trans-anethole, vanillin, ethyl vanillin, similar compositions, and

combinations thereof.

[0034] In still other embodiments, the bioactive agent may be an enzyme. As used herein, variants are understood to be included in the term enzyme. Suitable non-limiting examples of enzymes include amylases, carbohydrases, cellulases, esterases, galactonases, galactosidases, glucanases, hemicellulases, hydrolases, lipases, oxidoreductases, pectinases, peptidases, phosphatases, phospholipases, phytases, proteases, transferases, xylanases, and combinations thereof.

[0035] In alternate embodiments, the bioactive agent may be a probiotic or prebiotic. Probiotics and prebiotics may include yeast and bacteria that help establish an immune protective rumen or gut microflora as well as small oligosaccharides. By way of non-limiting example, yeast-derived probiotics and prebiotics include yeast cell wall derived components such as b-glucans, arabinoxylan isomaltose,

agarooligosaccharides, lactosucrose, cyclodextrins, lactose, fructooligosaccharides, laminariheptaose, lactulose, b-galactooligosaccharides, mannanoligosaccharides, raffinose, stachyose, oligofructose, glucosyl sucrose, sucrose thermal oligosaccharide, isomalturose, caramel, inulin, xylooligosaccharides, and selenium yeast. In an exemplary embodiment, the yeast-derived agent may be b-glucans and/or

mannanoligosaccharides. Sources for yeast cell wall derived components include Saccharomyces bisporus, Saccharomyces boulardii, Saccharomyces cerevisiae, Saccharomyces capsularis, Saccharomyces delbrueckii, Saccharomyces fermentati, Saccharomyces lugwigii, Saccharomyces microellipsoides, Saccharomyces

pastorianus, Saccharomyces rosei, Candida albicans, Candida cloaceae, Candida tropicalis, Candida utilis, Geotrichum candidum, Hansenula americana, Hansenula anomala, Hansenula winge i, and Aspergillus oryzae. Probiotics and prebiotics may also include bacteria cell wall derived agents such as peptidoglycan and other components derived from gram-positive bacteria with a high content of peptidoglycan. Exemplary gram-positive bacteria include Lactobacillus acidophilus, Bifedobact thermophilum, Bifedobat longhum, Streptococcus faecium, Bacillus pumilus, Bacillus subtilis, Bacillus licheniformis, Lactobacillus acidophilus, Lactobacillus casei, Enterococcus faecium, Bifidobacterium bifidium, Propionibacterium acidipropionici, Propionibacteriium freudenreichii, and Bifidobacterium pseudolongum.

[0036] In yet other embodiments, the bioactive agent may be an herb or herbal extract. Suitable herbals and herbal extracts, as used herein, refer to herbal derivatives, and substances derived from plants and plant parts, such as leaves, flowers and roots, without limitation. Non-limiting exemplary herbals and herbal derivatives include agrimony, alfalfa, aloe vera, amaranth, angelica, anise, barberry, basil, bayberry, bee pollen, birch, bistort, blackberry, black cohosh, black walnut, blessed thistle, blue cohosh, blue vervain, boneset, borage, buchu, buckthorn, bugleweed, burdock, capsicum, cayenne, caraway, cascara sagrada, catnip, celery, centaury, chamomile, chaparral, chickweed, chicory, chinchona, cloves, coltsfoot, comfrey, cornsilk, couch grass, cramp bark, culver's root, cyani, cornflower, damiana, dandelion, devils claw, dong quai, echinacea, elecampane, ephedra, eucalyptus, evening primrose, eyebright, false unicorn, fennel, fenugreek, figwort, flaxseed, garlic, gentian, ginger, ginseng, golden seal, gotu kola, gum weed, hawthorn, hops, horehound, horseradish, horsetail, hoshouwu, hydrangea, hyssop, Iceland moss, irish moss, jojoba, juniper, kelp, lady’s slipper, lemon grass, licorice, lobelia, mandrake, marigold, marjoram,

marshmallow, mistletoe, mullein, mustard, myrrh, nettle, oatstraw, Oregon grape, papaya, parsley, passion flower, peach, pennyroyal, peppermint, periwinkle, plantain, pleurisy root, pokeweed, prickly ash, psyllium, quassia, queen of the meadow, red clover, red raspberry, redmond clay, rhubarb, rose hips, rosemary, rue, safflower, saffron, sage, St. John’s wort, sarsaparilla, sassafras, saw palmetto, scullcap, senega, senna, shepherd's purse, slippery elm, spearmint, spikenard, squawvine, stillingia, strawberry, taheebo, thyme, uva ursi, valerian, violet, watercress, white oak bark, white pine bark, wild cherry, wild lettuce, wild yam, willow, wintergreen, witch hazel, wood betony, wormwood, yarrow, yellow dock, yerba santa, yucca and combinations thereof.

[0037] In further embodiments, the bioactive agent may be a pigment.

Suitable non-limiting pigments include actinioerythrin, alizarin, alloxanthin, p-apo-2'- carotenal, apo-2-lycopenal, apo-6'-lycopenal, astacein, astaxanthin, azafrinaldehyde, aacterioruberin, aixin, a-carotine, b-carotine, y-carotine, b-carotenone, canthaxanthin, capsanthin, capsorubin, citranaxanthin, citroxanthin, crocetin, crocetinsemialdehyde, crocin, crustaxanthin, cryptocapsin, a-cryptoxanthin, b-cryptoxanthin,

cryptomonaxanthin, cynthiaxanthin, decaprenoxanthin, dehydroadonirubin,

diadinoxanthin, 1 ,4-diamino-2,3-dihydroanthraquinone, 1 ,4-dihydroxyanthraquinone, 2,2'-Diketospirilloxanthin, eschscholtzxanthin, eschscholtzxanthone, flexixanthin, foliachrome, fucoxanthin, gazaniaxanthin, hexahydrolycopene, hopkinsiaxanthin, hydroxyspheriodenone, isofucoxanthin, loroxanthin, lutein, luteoxanthin, lycopene, lycopersene, lycoxanthin, morindone, mutatoxanthin, neochrome, neoxanthin, nonaprenoxanthin, OH-chlorobactene, okenone, oscillaxanthin, paracentrone, pectenolone, pectenoxanthin, peridinin, phleixanthophyll, phoeniconone,

phoenicopterone, phoenicoxanthin, physalien, phytofluene, pyrrhoxanthininol, quinones, rhodopin, rhodopinal, rhodopinol, rhodovibrin, rhodoxanthin, rubixanthone,

saproxanthin, semi-a-carotenone, semi-p-carotenone, sintaxanthin, siphonaxanthin, siphonein, spheroidene, tangeraxanthin, torularhodin, torularhodin methyl ester, torularhodinaldehyde, torulene, 1 ,2,4-trihydroxyanthraquinone, triphasiaxanthin, trollichrome, vaucheriaxanthin, violaxanthin, wamingone, xanthin, zeaxanthin, a- zeacarotene and combinations thereof.

[0038] In further embodiments, the bioactive agent may be a

pharmaceutically acceptable agent. Suitable non-limiting pharmaceutically acceptable agents include an acid/alkaline-labile drug, a pH dependent drug, or a drug that is a weak acid or a weak base. Examples of acid-labile drugs include statins (e.g., pravastatin, fluvastatin and atorvastatin), antibiotics (e.g., penicillin G, ampicillin, streptomycin, erythromycin, clarithromycin and azithromycin), nucleoside analogs [e.g., dideoxyinosine (ddl), dideoxyadenosine (ddA), dideoxycytosine (ddC)], salicylates, digoxin, bupropion, pancreatin, midazolam, and methadone. Drugs that are only soluble at acid pH include nifedipine, emonapride, nicardipine, amosulalol, noscapine, propafenone, quinine, dipyridamole, josamycin, dilevalol, labetalol, enisoprost, and metronidazole. Drugs that are weak acids include phenobarbital, phenytoin, zidovudine (AZT), salicylates (e.g., aspirin), propionic acid compounds (e.g., ibuprofen), indole derivatives (e.g., indomethacin), fenamate compounds (e.g., meclofenamic acid), pyrrolealkanoic acid compounds (e.g., tolmetin), cephalosporins (e.g., cephalothin, cephalaxin, cefazolin, cephradine, cephapirin, cefamandole, and cefoxitin), 6- fluoroquinolones, and prostaglandins. Drugs that are weak bases include adrenergic agents (e.g., ephedrine, desoxyephedrine, phenylephrine, epinephrine, salbutamol, and terbutaline), cholinergic agents (e.g., physostigmine and neostigmine), antispasmodic agents (e.g., atropine, methantheline, and papaverine), curariform agents (e.g., chlorisondamine), tranquilizers and muscle relaxants ( e.g ., fluphenazine, thioridazine, trifluoperazine, chlorpromazine, and triflupromazine), antidepressants (e.g., amitriptyline and nortriptyline), antihistamines (e.g., diphenhydramine, chlorpheniramine,

dimenhydrinate, tripelennamine, perphenazine, chlorprophenazine, and

chlorprophenpyridamine), cardioactive agents (e.g., verapamil, diltiazem, gallapomil, cinnarizine, propranolol, metoprolol and nadolol), antimalarials (e.g., chloroquine), analgesics (e.g., propoxyphene and meperidine), antifungal agents (e.g., ketoconazole and itraconazole), antimicrobial agents (e.g., cefpodoxime, proxetil, and enoxacin), caffeine, theophylline, and morphine. In another embodiment, the drug may be a biphosphonate or another drug used to treat osteoporosis. Non-limiting examples of a biphosphonate include alendronate, ibandronate, risedronate, zoledronate,

pamidronate, neridronate, olpadronate, etidronate, clodronate, and tiludronate. Other suitable drugs include estrogen, selective estrogen receptor modulators (SERMs), and parathyroid hormone (PTH) drugs. In yet another embodiment, the drug may be an antibacterial agent. Suitable antibiotics include aminoglycosides (e.g., amikacin, gentamicin, kanamycin, neomycin, netilmicin, streptomycin, and tobramycin), carbecephems (e.g., loracarbef) a carbapenem (e.g., certapenem, imipenem, and meropenem), cephalosporins (e.g., cefadroxil cefazolin, cephalexin, cefaclor, cefamandole, cephalexin, cefoxitin, cefprozil, cefuroxime, cefixime, cefdinir, cefditoren, cefoperazone, cefotaxime, cefpodoxime, ceftazidime, ceftibuten, ceftizoxime, and ceftriaxone), macrolides (e.g., azithromycin, clarithromycin, dirithromycin, erythromycin, and troleandomycin), monobactam, penicillins (e.g., amoxicillin, ampicillin, carbenicillin, cloxacillin, dicloxacillin, nafcillin, oxacillin, penicillin G, penicillin V, piperacillin, and ticarcillin), polypeptides (e.g., bacitracin, colistin, and polymyxin B), quinolones (e.g., ciprofloxacin, enoxacin, gatifloxacin, levofloxacin, lomefloxacin, moxifloxacin, norfloxacin, ofloxacin, and trovafloxacin), sulfonamides (e.g., mafenide, sulfacetamide, sulfamethizole, sulfasalazine, sulfisoxazole, and trimethoprim-sulfamethoxazole), and tetracyclines (e.g., demeclocycline, doxycycline, minocycline, and oxytetracycline). In an alternate embodiment, the drug may be an antiviral protease inhibitor (e.g., amprenavir, fosamprenavir, indinavir, lopinavir/ritonavir, ritonavir, saquinavir, and nelfinavir). In a still another embodiment, the drug may be a cardiovascular drug.

Examples of suitable cardiovascular agents include cardiotonic agents ( e.g ., digitalis (digoxin), ubidecarenone, and dopamine), vasodilating agents (e.g., nitroglycerin, captopril, dihydralazine, diltiazem, and isosorbide dinitrate), antihypertensive agents (e.g., alpha-methyldopa, chlortalidone, reserpine, syrosingopine, rescinnamine, prazosin, phentolamine, felodipine, propanolol, pindolol, labetalol, clonidine, captopril, enalapril, and lisonopril), beta blockers (e.g., levobunolol, pindolol, timolol maleate, bisoprolol, carvedilol, and butoxamine), alpha blockers (e.g., doxazosin, prazosin, phenoxybenzamine, phentolamine, tamsulosin, alfuzosin, and terazosin), calcium channel blockers (e.g., amlodipine, felodipine, nicardipine, nifedipine, nimodipine, nisoldipine, nitrendipine, lacidipine, lercanidipine, verapamil, gallopamil, and diltiazem), and anticlot agents (e.g., dipyrimadole).

[0039] The amount of bioactive agent present in the core can and will vary depending upon the identity of the bioactive agent. For example, the amount of bioactive agent in a core comprising a salt of the bioactive agent will be less than in a core comprising the free base of the bioactive agent. In general, the amount of the bioactive agent in the core may range from about 30% to about 99.9% by weight of the core. In various embodiments, the amount of the bioactive agent present in the core may be at least about 35 wt%, at least about 40 wt%, at least about 45 wt%, at least about 50 wt%, at least about 55 wt%, at least about 60 wt%, at least about 65 wt%, at least about 70 wt%, at least about 75 wt%, at least about 80 wt%, at least about 85 wt%, at least about 90 wt%, or at least about 95 wt% of the core. In one embodiment, the core may contain lysine sulfate and the amount of free lysine in the core may be about 55% by weight of the core. In another embodiment, the core may contain lysine hydrochloride and the amount of free lysine in the core may be about 75% by weight of the core.

(ii) Optional second bioactive agent

[0040] In some embodiments, the composition may comprise a second bioactive agent. The second bioactive agent may be chosen from any of those listed above in section (l)(a)(ii), provided that the second bioactive agent differs from the bioactive agent (i.e., the first bioactive agent) present in the core. In some

embodiments, the core contains both the first and the second bioactive agents. In other embodiments, the second bioactive agent may adhere to the surface of the core containing the first bioactive agent. As an example, a plurality of discrete particles of the second bioactive agent may adhere to the surface of the core. For this, cores comprising or consisting of the first bioactive agent may be mixed with a population of discrete particles of the second bioactive agent, wherein the discrete particles adhere to the surface of the core. The mixing may be dry blending, dry mixing, or via any other suitable means. The discrete particles of the second bioactive agent may have an average diameter of less than about 100 microns, less than about 50 microns, less than about 25 microns, less than about 10 microns, less than about 5 microns, less than about 2.5 microns, or less than about 1 micron. In another example, cores comprising or consisting of the first bioactive agent may comprise a surface coating comprising the second bioactive agent and at least one polymer (see, e.g., FIG. 7B). For this, the cores may be coated with a surface coating solution comprising the second bioactive agent and the at least one polymer, wherein the coating may be applied as detailed below in section (IV). Suitable polymers are detailed below in section (l)(b). In specific embodiments, the surface coating comprises a water soluble cellulose derivative. For example, the surface coating may comprise methyl cellulose. The surface coating may comprise from about 0.5% to about 10% by weight of the composition. In some embodiments, the surface coating comprising the second bioactive agent may comprise from about 1 % to about 5% by weight of the composition.

[0041 ] The weight ratio of the first bioactive agent in the core and the second bioactive agent adhering to the surface of the core may range from about 99:1 to about 1 :99. In various embodiments, the weight ratio of the first bioactive agent and the second bioactive agent may range from about 90: 1 , 60: 1 , 30: 1 , 10:1 , 3:1 , 1 :1 , 1 :3, 1 :10, 1 :30, 1 :60, 1 :90, or any ratio in between those listed above. (b) First coating layer

[0042] The compositions disclosed herein comprise a first coating layer that surrounds the irregularly-shaped core comprising or consisting of the bioactive agent, wherein the first coating layer comprising at least one polymer. The first coating layer substantially coats or covers the entire surface of the irregularly-shaped core.

Thus, the first coating layer functionally fill gaps or interstitial spaces of the irregularly- shaped core to form a more uniformly-shaped core or particle. See, e.g., FIGS. 1A, 3A, 5A, and 7C. The first coating layer, however, does not provide rumen protection or rumen bypass on its own.

[0043] The at least one polymer of the first coating layer may be a water- soluble cellulose ether, polyacrylate, polyalkylene succinate, polyalkylene oxalate, polyamide, polyarylate, polycarbonate, polycaprolactone, polycyanoacrylate,

polydioxane, polydioxanone, polyether ether ketone, polyethylene glycol, polyalkylene oxide, polyethylene terephthalate, polyhydroxyalkanoate, polyhydroxy ester, poly(2- hydroxy-4-methylthiobutanoate), polyimide, polyketal, polylactide, polymethacrylate, polyolefin, polyorthoester, polyphosphazene, polystyrene, polytetramethylene

carbonate, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl methyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or combination thereof. In various embodiments, the at least one polymer of the first coating layer may be a water- soluble cellulose ether, a polyalkylene oxide, a polyethylene glycol, a vinylpyridine polymer, a vinylpyridine and styrene copolymer, a vinylpyridine and vinylacetate copolymer, a vinylpyridine and methylacrylate copolymer, or a combination thereof.

[0044] In specific embodiments, the first coating layer may comprise a water-soluble cellulose ether. Non-limiting examples of suitable water-soluble cellulose ethers include hydroxypropyl methylcellulose, hydroxypropyl cellulose, methyl cellulose, carboxy methylcellulose, and so forth. In other embodiments, the first coating layer comprises a vinylpyridine polymer or a co-polymer comprising poly(vinylpyridine).

Suitable vinylpyridine monomers include, without limit, 2-vinylpyridine, 3-vinylpyridine, 4- vinylpyridine, 2-methyl-5-vinylpyridine, and 5-ethyl-2-vinylpyridine. In a further embodiment, the first coating layer may comprise a co-polymer of vinylpyridine and styrene. For example, the first coating layer may comprise poly(2-vinylpyridine-co- styrene). The weight ratio of 2-vinylpyridine to styrene in the co-polymer may range from about 10:90 to about 90: 10. In various embodiments, the weight ratio of 2- vinylpyridine to styrene may be about 10:90, about 15:85, about 20:80, about 25:75, about 30:70, about 35:65, about 40:60, about 45:55, about 50:50, about 55:45, about 60:40, about 65:35, about 70:30, about 75:25, about 80:20, about 85:15, about 90:10, or ratios between those listed. In specific embodiments, the weight ratio of 2-vinylpyridine to styrene may be about 70:30.

[0045] In embodiments in which the first coating layer comprises a vinylpyridine polymer or a co-polymer comprising poly(vinylpyridine), the first coating layer may further comprise a hydrophobic agent. Hydrophobic agents are generally those with a contact angle above 90°. Suitable hydrophobic agents include long chain fatty acids, long chain fatty acid esters, vegetable oils, waxes, or combinations thereof. Long chain fatty acids and long chain fatty acid esters generally have 14 or more carbons in the aliphatic chain. The long chain fatty acid or long chain fatty ester may be saturated or unsaturated. Non-limiting examples of suitable long chain fatty acids include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, and so forth. Long chain fatty acid esters are esters of glycerol and a long chain fatty acid as described above, and include monoglycerides, diglycerides, and triglycerides. Non-limiting examples of suitable vegetable oils include canola oil, coconut oil, corn oil, cottonseed oil, lauric acid, linoleic acid, oleic acid, palm oil, palmitic acid, soy oil, soybean oil, stearic acid, stearin, sunflower seed oil, vegetable oil, or the hydrogenated forms of any of these, and combinations thereof. Suitable waxes include natural and synthetic waxes, e.g., beeswax, carnuba wax, cetyl palmitate, hydrogenated jojoba oil, lanolin, lignoeric acid, paraffin wax, and the like. In specific embodiments, the hydrophobic agent is a long chain fatty acid. The weight ratio of the vinylpyridine polymer or copolymer comprising poly(vinylpyridine) to the hydrophobic agent may range from about 1 :0.1 to about 1 :20. In certain embodiments, the weight ratio may range from about 1 :5 to about 1 :15, from about 1 :8 to about 1 :10, or about 1 :9. [0046] In one embodiment, the first coating layer comprises or consists of hydroxypropyl methylcellulose. In another embodiment, the first coating layer comprises or consists of methyl cellulose. In a further embodiment, the first coating layer comprises a mixture of poly(2-vinylpyridine-co-styrene) and stearic acid, wherein the ratio of poly(2-vinylpyridine-co-styrene) to stearic acid is about 1 :9. In additional embodiments, the first coating layer may further comprise a polymer of 2-hydroxy-4- methylthiobutanoate.

[0047] The weight percentage of the first coating layer can and will vary.

In general, the first coating layer comprises from about 3% to about 20% by weight of the composition. In embodiments in which the first coating layer comprises a water- soluble cellulose ether, the first coating layer may comprise from about 4 wt% to about 10 wt%, from about 5 wt% to about 8 wt%, or from about 6 wt% to about 7 wt% of the total composition. In specific embodiments in which the first coating layer comprises a water-soluble cellulose ether, the first coating layer may comprise about 6% or about 6.4% by weight of the composition. In embodiments in which the first coating layer comprises a mixture of poly(2-vinylpyridine-co-styrene) and stearic acid, the first coating layer may comprise from about 8 wt% to about 18 wt%, from about 10 wt% to about 15 wt%, from about 11 wt% to about 14 wt%, or from about 12 wt% to about 13 wt% of the total composition. In specific embodiments in which the first coating layer comprises a mixture of poly(2-vinylpyridine-co-styrene) and stearic acid, the first coating layer may comprise about 12.3% or 12.5% by weight of the composition.

(c) Second coating layer

[0048] The compositions disclosed herein also comprise a second coating layer that surrounds the first coating layer, wherein the second coating layer comprises at least one pH responsive polymer. The second coating layer substantially coats or covers the entire surface of the first coating layer. See, e.g., FIGS. 1B, 3B, 5B, and 7D. The second coating layer, without the first coating layer, does not provide rumen protection or rumen bypass. Rather, rumen protection or rumen bypass is provided by the combination of the first and the second coating layers. [0049] The at least one pH response polymer of the second coating layer may be polyacrylonitrile, poly(acrylic acid), poly(methacrylic acid), poly(benzyl acrylate), poly(butyl acrylate), poly(ethyl acrylate), poly(dialkylamino ethyl acrylate), poly(2- ethylhexyl acrylate), poly(methyl acrylate), poly(propyl acrylate), poly(phenyl acrylate), poly(aminoethyl methacrylate), poly(butyl methacrylate), poly(benzyl methacrylate), poly(2-ethylhexyl methacrylate), poly(glycidyl methacrylate), poly(hydroxybutyl methacrylate), poly(2-hydroxyethyl methacrylate), poly(hydroxypropyl methacrylate), poly(methyl methacrylate), poly(phenyl methacrylate), poly(2-acrylamido-2-methyl-1 - propanesulfonic acid), poly(maleic acid), poly(maleic anhydride), polystyrene, polyvinyl acetate, poly(N-vinyl acetamide), poly(N-vinyl formamide), polyvinylpyridine, co-polymer thereof, or combination thereof.

[0050] In some embodiments, the at least one pH responsive polymer in the second coating layer may be a vinylpyridine polymer or a co-polymer comprising poly(vinylpyridine). Suitable vinylpyridine monomers include, without limit, 2- vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, and 5-ethyl-2- vinylpyridine. In certain embodiments, the pH response polymer may be a co-polymer of vinylpyridine and styrene. For example, the pH response polymer in the second coating layer may be poly(2-vinylpyridine-co-styrene). The weight ratio of 2- vinylpyridine to styrene in the co-polymer may range from about 10:90 to about 90:10.

In various embodiments, the weight ratio of vinylpyridine to styrene may be about 10:90, about 15:85, about 20:80, about 25:75, about 30:70, about 35:65, about 40:60, about 45:55, about 50:50, about 55:45, about 60:40, about 65:35, about 70:30, about 75:25, about 80:20, about 85:15, about 90:10, or ratios between those listed. In specific embodiments, the weight ratio of 2-vinylpyridine to styrene may be about 70:30.

[0051 ] In general, the second coating layer further comprises at least one hydrophobic polymer, at least one hydrophobic agent, or a combination thereof.

[0052] Non-limiting examples of suitable hydrophobic polymers include water-insoluble cellulose ethers, poly(alkyl acrylate), poly(alkyl methacrylate),

polyamide, polyimide, polybutadiene, polyisoprene, poly(alkylene succinate),

polyalkylene terephthalate), polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl ether, polyvinyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or combinations thereof. Suitable water-insoluble cellulose ethers include ethyl cellulose, ethyl methyl cellulose, and ethyl hydroxyethyl cellulose. In specific

embodiments, the hydrophobic polymer in the second coating layer may be ethyl cellulose. The weight ratio of the pH response polymer to the hydrophobic polymer in the second coating layer may range from about 1 :0.4 to about 1 :1 , from about 1 :0.08 to about 1 :0.5, from about 1 :0.1 to about 1 :0.3, or about 1 :0.2.

[0053] Suitable hydrophobic agents include long chain fatty acids, long chain fatty acid esters, vegetable oils, waxes, or combinations thereof. Long chain fatty acids and long chain fatty esters generally have 14 or more carbons in the aliphatic chain. The long chain fatty acid or long chain fatty ester may be saturated or

unsaturated. Non-limiting examples of suitable long chain fatty acids include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, linoleic acid, and so forth. Long chain fatty acid esters are esters of glycerol and a long chain fatty acid as described above, and include monoglycerides, diglycerides, and triglycerides. Non-limiting examples of suitable vegetable oils include canola oil, coconut oil, corn oil, cottonseed oil, lauric acid, linoleic acid, oleic acid, palm oil, palmitic acid, soy oil, soybean oil, stearic acid, stearin, sunflower seed oil, vegetable oil, or the hydrogenated forms of any of these, and combinations thereof. Suitable waxes include natural and synthetic waxes, e.g., beeswax, carnuba wax, cetyl palmitate, hydrogenated jojoba oil, lanolin, lignoceric acid, paraffin wax, and the like. In specific embodiments, the hydrophobic agent in the second coating layer may be a long chain fatty acid. The weight ratio of the pH response polymer to the hydrophobic agent in the second coating layer may range from about 1 :0.8 to about 1 :20, from about 1 : 1 to about 1 :8, from about 1 :3 to about 1 :5, or about 1 :4.

[0054] The weight percentage of the second coating layer can and will vary. In general, the second coating layer comprises from about 5% to about 15% by weight of the composition. In various embodiments, the second coating layer may comprise from about 6 wt% to about 14 wt%, from about 7 wt% to about 13 wt%, from about 8 wt% to about 12 wt%, or from about 9 wt% to about 12 wt% of the composition. In specific embodiments, the second coating layer may comprise about 10% by weight, or about 10.7% by weight of the composition.

(d) Exemplary compositions

[0055] In specific embodiments, the composition comprises an irregularly- shaped core comprising or consisting of lysine sulfate, a first coating layer comprising hydroxypropyl methylcellulose or methyl cellulose, and a second coating layer comprising stearic acid, poly(2-vinylpryridien-co-styrene), and ethyl cellulose. In other embodiments, the composition comprises an irregularly-shaped core comprising or consisting of lysine hydrochloride, a first coating layer comprising stearic acid and poly(2-vinylpryridien-co-styrene), and a second coating layer comprising stearic acid, poly(2-vinylpryridien-co-styrene), and ethyl cellulose. In further embodiments, the composition comprises an irregularly-shaped core comprising or consisting of a choline salt, and first and second coating layers as described above. Any of the foregoing compositions may further comprise a second bioactive agent adhering to the surface of the irregularly-shaped core.

(e) Properties

[0056] The compositions comprising first and second coating layers surrounding irregularly-shaped, bioactive-containing cores are substantially stable in aqueous media having approximately neutral pH values, but hydrolyze at lower pH values. Hydrolysis of the composition results in release of the bioactive agent from the composition. The compositions disclosed herein, therefore, are stable in the neutral pH environment of the rumen, but release the bioactive agent in the lower pH environment of abomasum after passage from the rumen.

[0057] Release of the bioactive agent from the compositions disclosed herein occurs in aqueous media having pH levels of less than about 5.0. In various embodiments, the compositions release the bioactive agent at pH levels of less than about 4.5, less that about 4.0, less than about 3.5, or less than about 3.0. In certain embodiments, the compositions disclosed herein release the bioactive agent in aqueous medium having a pH of 2.5 (see FIGS. 2, 4, 6, and 8).

[0058] In general, more than about 20% of the bioactive agent is released from the composition at a pH of less than about 5.0. In various embodiments, more than about 25%, more than about 30%, more than about 35%, more than about 40%, more than about 45%, more than about 50%, more than about 55%, more than about 60%, more than about 65%, more than about 70%, more than about 75%, more than about 80%, more than about 85%, more than about 90%, more than about 95% of the bioactive agent is released from the composition at pH values of less than about 5.0.

[0059] In embodiments in which the core consists of lysine sulfate, the core contains about 55% of free lysine. In such embodiments, more than about 20%, more than about 25%, more than about 30%, more than about 35%, more than about 40%, more than about 45%, or more than about 50% of free lysine is released in an aqueous medium whose pH is less that about 5.0. In embodiments in which the core consists of lysine hydrochloride, the core contains about 75% of free lysine. In such embodiments, more than about 20%, more than about 25%, more than about 30%, more than about 35%, more than about 40%, more than about 45%, more than about 50%, more than about 55%, more than about 60%, or more than about 65% of free lysine is released in an aqueous medium whose pH is less that about 5.0.

[0060] At pH levels of less than 5.0, the compositions may have a release profile for the bioactive agent which is substantially constant, first-order, sigmoidal, or delayed. Generally, the release rate at a pH of less than 5.0 is higher than the release rate at approximately neutral conditions. In some embodiments, the compositions have a substantially constant release profile. A substantially constant release refers to release of a bioactive that is constant over a period of time, for example, varying by less than 1 %, less than 0.5%, or 0.25% in different embodiments. The compositions may show a constant release rate at a pH below about 5.0 for a period of 1 to 24 hours. In some embodiments, the release rate is constant over a period of about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, or about 24 hours. Depending on the time period and pH, the release of the bioactive may range from less than 1 % per hour to more than 30% per hour. In other embodiments, the release profile may show an initial high rate of release at a pH of less than about 5.0. In such embodiments, the release rates at a pH of about 5.0 or lower may be greater over the first 1 to 5 hours at a pH of about 5.0 or lower. In some embodiments, this initial period of rapid release of bioactive is followed by a period of constant release.

[0061 ] The release profile is tunable based on the amounts and identities of the pH sensitive polymer and the hydrophobic polymer in the second coating layer. For example, higher levels may correspond to lower rate of release, while lower levels may correspond to higher rates of release.

[0062] The compositions are substantially stable at pH levels of about 6.0, about 6.5, about 7.0, and about 7.5. At an approximately neutral pH, the compositions may be characterized by minimal release of the bioactive. In one embodiment, the compositions may release less than about 20% of the bioactive agent at an

approximately neutral pH. In other embodiments, a minimum release is characterized a release of less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, less than 11 %, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1 % of the bioactive agent at approximately neutral pH levels.

[0063] The compositions disclosed herein have improved durability, plasticity, and mechanical properties. Such properties are advantageous for compositions that may be subject to mastication (/. e. , in the context of providing the composition to an animal) or in the context of mechanical stresses of industrial processing such as mixing and conveying equipment. Resiliency of the compositions against mechanical force can be measured by impact tests, which are known in the art. For example, the composition may be contacted with a weight of a specific mass (e.g., 95 gram) from a specific height (e.g., 2 feet) and then release of the bioactive may be measured. In some embodiments, the compositions disclosed herein release less than 10% of the bioactive agent at substantially neutral pH after being subjected to 25 contact hits. In other embodiments, the compositions release less than 9%, or less than 8% or less than 7%, or less than 6% or less than 5%, or less than 4%, or less than 3%, or less than 2% or less than 1 % of the bioactive agent at a substantially neutral pH when subjected to 25 contact hits.

(II) Feed Premixes

[0064] A further aspect of the present disclosure encompasses feed premixes comprising any of the compositions comprising two coating layers, as described above in section (I).

[0065] The weight fraction of the composition comprising two coating layers in the feed premix may be about 99% or less, about 98% or less, about 95% or less, about 90% or less, about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, about 60% or less, about 55% or less, about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 10% or less, about 5% or less, about 2%, or about 1 % or less of the total weight of the composition.

[0066] The feed premix may comprise one or more amino acids, amino acid analogs, vitamins, minerals, antioxidants, organic acids, polyunsaturated fatty acids, essential oils, enzymes, prebiotics, probiotics, herbal extracts, or pigments, examples of which are detailed above in section (l)(a)(i). The feed premix may also comprise one or more mycotoxin binders, approved antibiotics, antiparasitic agents, ionophores, or excipients.

[0067] Examples of suitable mycotoxin binders include, without limit, charcoal, activated carbon, silicates (e.g., phyllosilicates, tectosilicates, aluminosilicates, hydrated sodium calcium aluminosilicates, bentonites, zeolites, clinoptilolites,

montmorillonites, and modified versions thereof), organic polymers (e.g., cellulose, glucomannans, peptidoglycans, and modified versions thereof), synthetic polymers (e.g., cholestyramine, polyvinylpyrrolidone, and the like), yeast cell wall extracts, and bacterial extracts. Non-limiting examples of antibiotics approved for use in livestock and poultry include bacitracin, carbadox, ceftiofur, enrofloxacin, florfenicol, laidlomycin, linomycin, oxytetracycline, roxarsone, tilmicosin, tylosin, and virginiamycin. Examples of suitable antiparasitic agents include but are not limited to abamectn, afloxolaner, albendazole, alphamethrin, amitraz, azamethiphos, carbaryl, chlorfenvinphos, chlorpyrifos, clorsulon, closantel, coumaphos, cyfluthrin, cyhalothrin, cymiazol, cypermethrin, cyromazine, ceclorcos, deltamethrin, diazinon, dichlorvos, dicyclanil, diflubenzuron, doramectin, dympilate, eprinomectin, ethion, febtantel, fenbendazole, fenitrothion, fenthion, fenvalerate, fipronil, fluazuron, flubendazole, flumethrin, imidacloprid, ivermectin, levamisole, lufenuron, malathion, mebendazole, metrifonate, methoprene, milbemycin oxime, monepantel, morantal, moxidectin, netobimin, niclosamide, nitroxinil, oxfendazole, oxibendazole, oxyclozanide, permethrin, phosmet, phoxim, piperazine, praziquantel, propoxur, pyrantel, rafoxanide, ribobendazole, rofenone, selamectin, spinosad, trichlorfon, thiabendazole, thiamethoxam, thiophanate, triclabendazole, and triflumuron. Suitable ionophores include but are not limited to bambermycin, decoquiate, declazuril, lasalocid, maduramicin, monensin, narasin, nicarazin, nystatin, robenedine, salinomycin, semduramicin, variants, or derivatives thereof.

[0068] Suitable excipients include fillers, diluents, binders, pH modifiers, anti-caking agents, disintegrants, lubricants, dispersants, preservatives, flavoring agents, sweetening agents, taste masking agents, coloring agents, and combinations thereof. Examples of suitable fillers include, without limit, carbohydrates, inorganic compounds, and polyvinylpyrrolidone. By way of non-limiting example, the filler may be calcium sulfate, both di- and tri-basic, starch, calcium carbonate, magnesium carbonate, microcrystalline cellulose, dibasic calcium phosphate, magnesium carbonate,

magnesium oxide, calcium silicate, talc, modified starches, lactose, sucrose, mannitol, and sorbitol. Diluents suitable for inclusion include saccharides such as sucrose, dextrose, lactose, microcrystalline cellulose, fructose, xylitol, and sorbitol, polyhydric alcohols, starches, pre-manufactured direct compression diluents, and mixtures of any of the foregoing. Non-limiting examples of suitable binders include starches, pregelatinized starches, gelatin, polyvinylpyrrolidone, cellulose, methylcellulose, sodium carboxymethylcellulose, ethylcellulose, polyacrylamides, polyvinyloxoazolidone, polyvinylalcohols, C12-C18 fatty acid alcohol, polyethylene glycol, polyols, saccharides, oligosaccharides, polypeptides, oligopeptides, and combinations thereof. The polypeptide may be any arrangement of amino acids ranging from about 100 to about 300,000 daltons. Suitable pH modifiers include, without limit, sodium carbonate, sodium bicarbonate, citric acid, tartaric acid, and the like. Examples of anti-caking agents include magnesium stearate, magnesium sulfate, magnesium oxide, sodium

bicarbonate, sodium silicate, silicon dioxide, talc, and combinations thereof. Suitable disintegrants include, without limit, starches such as corn starch, potato starch, pregelatinized and modified starches thereof, sweeteners, clays, such as bentonite, micro-crystalline cellulose, alginates, sodium starch glycolate, gums such as agar, guar, locust bean, karaya, pecitin, tragacanth, and combinations thereof. Non-limiting examples of lubricants include magnesium stearate, calcium stearate, zinc stearate, hydrogenated vegetable oils, sterotex, polyoxyethylene monostearate, talc,

polyethyleneglycol, sodium benzoate, sodium lauryl sulfate, magnesium lauryl sulfate, and light mineral oil. Suitable dispersants include starch, alginic acid,

polyvinylpyrrolidones, guar gum, kaolin, bentonite, purified wood cellulose, sodium starch glycolate, isoamorphous silicate, and microcrystalline cellulose as high HLB emulsifier surfactants. Suitable examples of preservatives include, but are not limited to, antioxidants, such as a-tocopherol or ascorbate, and antimicrobials, such as parabens, chlorobutanol or phenol. Flavoring agents may be chosen from synthetic flavor oils and flavoring aromatics and/or natural oils, extracts from plants, leaves, flowers, fruits, and combinations thereof. By way of example, these may include cinnamon oils, oil of wintergreen, peppermint oils, clover oil, hay oil, anise oil, eucalyptus, vanilla, citrus oil, such as lemon oil, orange oil, grape and grapefruit oil, fruit essences including apple, peach, pear, strawberry, raspberry, cherry, plum, pineapple, and apricot. Suitable sweetening agents glucose (corn syrup), dextrose, invert sugar, fructose, and mixtures thereof (when not used as a carrier); saccharin and its various salts such as the sodium salt; dipeptide sweeteners such as aspartame; dihydrochalcone compounds, glycyrrhizin; Stevia Rebaudiana (Stevioside); chloro derivatives of sucrose such as sucralose; sugar alcohols such as sorbitol, mannitol, sylitol, and the like. Taste-masking agents include cellulose hydroxypropyl ethers, low- substituted hydroxypropyl ethers, cellulose hydroxypropyl methyl ethers,

alklylcelluloses, hydroxy- or carboxy-substituted alkyl celluloses, acrylic polymers, cellulose acetate phthalate, cyclodextrins, and mixtures thereof. Suitable color agents include food, drug and cosmetic colors (FD&C), drug and cosmetic colors (D&C), or external drug and cosmetic colors (Ext. D&C). These colors or dyes, along with their corresponding lakes, and certain natural and derived colorants may be suitable for use in the present composition depending on the embodiment.

[0069] The feed premix may be a pelleted mixture, a granular mixture, a particulate mixture, a tablet, or a capsule.

(Ill) Feed Compositions

[0070] Another aspect of the present disclosure provides feed

compositions comprising any of the compositions comprising two coating layers as described above in section (I), and at least one nutritive agent.

[0071 ] The weight fraction of the composition comprising two coating layers in the feed composition may be about 99% or less, about 98% or less, about 95% or less, about 90% or less, about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, about 60% or less, about 55% or less, about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, about 10% or less, about 5% or less, about 2%, or about 1 % or less of the total weight of the composition.

[0072] The at least one nutritive agent may be a carbohydrate source, a fat source, a protein source, an amino acid or derivative thereof, or combination thereof.

[0073] Suitable carbohydrate sources may be chosen from those known in the art and include, without limitation, alginate, arrowroot, barley, canola, cassava, corn, corn syrup, cottonseed meal, fructose, glucose, galactose, grain sorghum, kelp meal, lactose, maize, maltose, mannose, potatoes, oats, rice, rye, sago, sorbitol, soybeans, tapioca, wheat, wheat gluten, yam, and combinations thereof.

[0074] The fat source may be an inert fat or a non-inert fat. Non-limiting examples of non-inert fats include plant derived oils (e.g., canola oil, corn oil,

cottonseed oil, palm oil, peanut oil, safflower oil, soybean oil, and sunflower oil), fish oils (e.g., menhaden oil, anchovy oil, albacore tuna oil, cod liver oil, herring oil, lake trout oil, mackerel oil, salmon oil, and sardine oil), animal fats (e.g., poultry fat, beef tallow, butter, pork lard, and whale blubber), yellow grease (i.e., waste grease from restaurants and low-grade fats from rendering plants), and combinations thereof. The non-inert fat source may also be a high fat product such as fish meal (e.g., menhaden meal, anchovy meal, herring meal, pollack meal, salmon meal, tuna meal, and whitefish meal), oilseeds (e.g., canola seeds, cottonseeds, flax seeds, linseeds, Niger seeds, sesame seeds, soy beans, and sunflower seeds), or distillers grains (e.g., dried distillers grains and solubles (DDGS) and wet distillers grains). The fat source may be a ruminally inert fat. Suitable examples of ruminally inert fats include calcium salts of palm fatty acids (e.g.,

MEGALAC ® ), saturated free fatty acids, or hydrogenated tallow (e.g., ALIFET ® ).

[0075] Suitable protein sources may be animal-derived proteins, plant- derived proteins, algal-derived proteins, or combinations thereof. In some

embodiments, suitable sources of animal derived protein include blood meal, bone meal, fish meal, fish processing by-products, meat meal, meat and bone meal, poultry by-produce meal, feather meal, and combinations thereof. In other embodiments, suitable sources of plant-derived proteins include grains such as corn, oats, soybean, and the like; grain protein concentrates such as soy protein concentrate; legumes such as peas, lupine, alfalfa; distiller’s grains; oilseed meals such as canola meal, cottonseed meal, flaxseed meal, soybean meal, sunflower seed meal; and combinations thereof. Suitable amino acids or derivatives thereof are described above in section (l)(a)(i).

[0076] The feed composition may also comprise at least one agent chosen from essential oils, metal chelates, minerals, amino acids, organic acids, vitamins, antioxidants, polyunsaturated fatty acids, prebiotics, probiotics, enzymes, ionophores, mycotoxin binders, antiparasitic agents, antibiotics, herbal extracts, pigments, excipients, or combinations thereof (see section (II)).

[0077] The feed composition may be formulated as pellets, granulates, extrudates, particulate blends, meal cakes, crumbled diets, gelled masses, and the like.

(IV) Processes for Preparing Compositions Comprising Two Coating Layers

[0078] Another aspect of the present disclosure encompasses process for preparing the compositions comprising two coating layers. The processes comprise forming a first coating layer over the irregularly-shaped core and then forming a second coating layer over the coated core.

[0079] The layers may be formed by fluid bed coating, Wurster coating, spray coating, thermal spraying, cold spraying, spray gun coating, dip coating, vacuum film coating, and so forth. Such coating processes are well-known in the art.

[0080] The polymer or polymers in the coating layer are generally dissolved in a solvent to form a coating solution prior to the coating step. The solvent may be a protic polar solvent, an aprotic polar solvent, or a nonpolar solvent. Non- limiting examples of suitable protic polar solvents include water; an alcohol such as methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, s-butanol, f-butanol, and the like; a diol such as propylene glycol; an organic acid such as formic acid, acetic acid, and so forth; an amide such as formamide, acetamide, and the like; and

combinations of any of the above. Suitable aprotic solvents include, without limit, acetone, acetonitrile, diethoxymethane, L/,/V-dimethylformamide, dimethyl sulfoxide, L/,/V-dimethylpropionamide, 1 ,3-dimethyl-3,4,5,6-tetrahydro-2(1 /-/)-pyrimidinone, 1 ,3- dimethyl-2-imidazolidinone, 1 ,2-dimethoxyethane (DME), dimethoxymethane, bis(2- methoxyethyl)ether, L/,/V-dimethylacetamide, A/-methyl-2-pyrrolidinone, 1 ,4-dioxane, formamide, hexachloroacetone, hexamethylphosphoramide, /V-methylacetamide, methylethyl ketone, methylisobutyl ketone, /V-methylformamide, methylene chloride, methoxyethane, morpholine, nitrobenzene, nitromethane, propionitrile, propyl acetates, sulfolane, tetramethylurea, tetrahydrofuran, 2-methyl tetrahydrofuran, tetrahydropyran, trichloromethane, and combinations thereof . Non-limiting examples of suitable nonpolar solvents include benzene, butyl acetate, tert-butyl methyl ether,

chlorobenzene, chloroform, chloromethane, cyclohexane, dichloromethane,

dichloroethane, di-tert-butyl ether, dimethyl ether, diethylene glycol, diethyl ether, diglyme, diisopropyl ether, ethyl tert-butyl ether, ethylene oxide, fluorobenzene, heptane, hexane, methyl tert-butyl ether, toluene, and combinations thereof.

[0081 ] The coating process may occur at a temperature ranging from about 10°C to about 150°C. In some embodiments, the temperature of the coating process may range from about 30°C to about 100°C. In certain embodiment, the coating process may occur at a temperature ranging from about 35°C to about 50°C, form about 55°C to about 85°C, or from about 90°C to about 95°C. The duration of the coating process can and will vary depending upon the temperature, the concentration of the polymer(s) in the coating solution, and the desired coating level.

[0082] In some embodiments, the irregularly-shaped core comprising a first bioactive agent may comprise a plurality of discrete particles of a second bioactive agent adhering to the surface. The discrete particles of the second bioactive agent may be dry blended with the irregularly-shaped cores. Alternatively, the irregularly-shaped cores may be dry coated with the plurality of the discrete particles of the second bioactive agent discrete particles of second bioactive agent. In other embodiments, the irregularly-shaped core comprising a first bioactive agent may comprise a surface coating comprising the second bioactive agent and at least one polymer. The surface coating may be applied by in a manner to the first and second coating layers as described above.

(V) Method for Providing Bioactive Agent(s) to a Subject

[0083] Still another aspect of the present disclosure encompasses a method from providing at least one bioactive agent to a subject. The method comprises administering to the subject a composition comprising the bioactive agent. The composition comprising the bioactive agent may be the composition comprising two coating layers as described above in section (I), a feed premix comprising the

composition comprising two coating layers as described above in section (II), or a feed composition comprising the composition comprising two coating layers as described above in section (III).

[0084] The composition comprising the bioactive agent may be

administered by variety of routes such as, e.g., oral, transmucosal, topical, or

parenteral. A preferred route of administration is oral. The composition may be administered to the subject as a particulate, as solid dosage form (e.g., tablet, caplet, capsule, etc.), or as a powder or granulate. The composition may be administered once a week, several times a week, once a day, or two or more times a day.

[0085] The composition comprising the bioactive agent may be used for the delivery of amino acids, amino acid analogs, vitamins, minerals (/. e. , organic or inorganic), antioxidants, organic acids, polyunsaturated fatty acids, essential oils, enzymes, prebiotics, probiotics, herbal extracts, or pigments to a subject in need thereof. In some embodiments, the composition may be used for the treatment of deficiencies, for example, amino acid deficiencies, vitamin deficiencies, mineral deficiencies, and the like.

[0086] The composition may be administered to a variety of subjects. Suitable subjects include humans, food animals, companion animals, research animals, and zoo animals. Non-limiting examples of food animals include ruminants (e.g., beef cattle, dairy cows, sheep, goats, and bison) and monogastrics (e.g., pigs and avian such as chickens, ducks, emu, game hens, geese, guinea fowl/hens, quail, ostriches, and turkeys). Additional monogastric species include aquatic species (e.g., fish and crustaceans including, but not limited to, salmon, shrimp, carp, tilapia and shell fish). Suitable companion animals include, but are not limited to, cats, dogs, horses, rabbits, rodents (e.g., mice, rats, hamsters, gerbils, and guinea pigs), hedgehogs, and ferrets. Examples of research animals include rodents, cats, dogs, rabbits, pigs, and non- human primates. Non-limiting examples of suitable zoo animals include non-human primates, lions, tigers, bears, elephants, giraffes, and the like. In specific embodiments, the subject is a ruminant. Non-limiting examples of ruminants include dairy cattle, beef cattle, sheep, goats, bison, deer, moose, elk, reindeer, caribou, camels, giraffes, antelope, and llama. [0087] The composition comprising the bioactive agent and the two coating layers is stable in an aqueous solution under approximately neutral pH. For example, the composition is stable at a pH level of about 6.0, about 6.5, about 7.0, and about 7.5. The composition comprising the bioactive agent and two coating layers hydrolyzes in an aqueous solution having a pH of less than about pH 5.0. Hydrolysis of the composition releases the bioactive agent. Thus, at pH levels less than about 5.0, the composition undergoes hydrolysis and releases the bioactive agent.

[0088] In embodiments in which the subject is a ruminant, therefore, the composition remains stable and is not degraded during the time in which the

composition is in the rumen of the subject. Upon entry into abomasum, in which the pH is low, the composition hydrolyzes and releases the bioactive agent. Accordingly, the compositions may be used for rumen bypass as the bioactive agent is protected from degradation or hydrolysis by the two coating layers and the bioactive agent is selectively released in the low pH environment of the abomasum. In embodiments in which the subject is a dairy cow or a lactating dairy cow, release of the composition in the abomasum and absorption from the small intestine may lead to increased milk production, increased milk protein, or increased milk fat.

DEFINITIONS

[0089] When introducing elements of the embodiments described herein, the articles "a " "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0090] The term“about,” particularly in reference to a given quantity, is meant to encompass deviations of plus or minus five percent.

[0091 ] As used herein, the term "pH responsive polymer" refers to a polymer whose solubility, volume, and chain conformation can be manipulated by changes in pH, co-solvent, or electrolytes. [0092] The term "long chain fatty acid" or "long chain fatty acid esters" generally have 14 or more carbons in the aliphatic chain.

ENUMERATED EMBODIMENTS

[0093] The following enumerated embodiments are presented to illustrate certain aspects of the present invention, and are not intended to limit its scope.

[0094] 1. A composition comprising (a) an irregularly-shaped core comprising a bioactive agent; (b) a first coating layer surrounding the irregularly-shaped, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases the bioactive agent in an aqueous medium whose pH is less than about 5.0.

[0095] 2. The composition of embodiment 1 , wherein the bioactive agent in the irregularly-shaped core is an amino acid, an amino acid analog, a vitamin, a mineral, an antioxidant, an organic acid, a polyunsaturated fatty acid, an essential oil, an enzyme, a prebiotic, a probiotic, an herb, a pigment, or a pharmaceutically active agent.

[0096] 3. The composition of embodiments 1 or 2, wherein the irregularly- shaped core comprises or consists of a salt of lysine, a salt of choline, or a salt of histidine.

[0097] 4. The composition of any one of embodiments 1 to 3, wherein the irregularly-shaped core is devoid of binders, fillers, diluents, or combinations thereof.

[0098] 5. The composition of any one of embodiments 1 to 4, wherein the irregularly-shaped core has a diameter ranging from about 200 microns to about 3000 microns.

[0099] 6. The composition of any one of embodiments 1 to 5, wherein the irregularly-shaped core comprises a plurality of discrete particles of a second bioactive agent adhering to its surface; or the irregularly-shaped core comprises a surface coating comprising a second bioactive agent and at least one polymer, provided the second bioactive agent differs from the bioactive agent present in the irregularly-shaped core. [0100] 7. The composition of any one of embodiments 1 to 6, wherein the at least one polymer in the first coating layer is a water-soluble cellulose ether, polyacrylate, polyalkylene succinate, polyalkylene oxalate, polyamide, polyarylate, polycarbonate, polycaprolactone, polycyanoacrylate, polydioxane, polydioxanone, polyether ether ketone, polyethylene glycol, polyalkylene oxide, polyethylene

terephthalate, polyhydroxyalkanoate, polyhydroxy ester, poly(2-hydroxy-4- methylthiobutanoate), polyimide, polyketal, polylactide, polymethacrylate, polyolefin, polyorthoester, polyphosphazene, polystyrene, polytetramethylene carbonate, polyurethane, polyvinyl acetate, polyvinyl alcohol, polyvinyl methyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or combination thereof.

[0101 ] 8. The composition of embodiment 7, wherein the at least one polymer in the first coating layer is a water-soluble cellulose ether.

[0102] 9. The composition of embodiment 8, wherein the first coating layer comprises about 4% to about 10% by weight of the composition.

[0103] 10. The composition of embodiment 7, wherein the at least one polymer in the first coating layer is a vinylpyridine styrene co-polymer.

[0104] 11. The composition of embodiment 10, wherein the first coating layer further comprises a hydrophobic agent chosen from a long chain fatty acid, a long chain fatty acid ester, a vegetable oil, a wax, or a combination thereof.

[0105] 12. The composition of embodiment 11 , wherein the hydrophobic agent is a long chain fatty acid.

[0106] 13. The composition of any one of embodiments 10 to 12, wherein the first coating layer comprises about 8% to about 18% by weight of the composition.

[0107] 14. The composition of any one of embodiments 8 to 13, wherein the first coating layer further comprises a polymer of 2-hydroxy-4-methylthiobutanoate.

[0108] 15. The composition of any one of embodiments 1 to 13, wherein the at least one pH responsive polymer in the second coating layer is polyacrylonitrile, poly(acrylic acid), poly(methacrylic acid), poly(benzyl acrylate), poly(butyl acrylate), poly(ethyl acrylate), poly(dialkylamino ethyl acrylate), poly(2-ethylhexyl acrylate), poly(methyl acrylate), poly(propyl acrylate), poly(phenyl acrylate), poly(aminoethyl methacrylate), poly(butyl methacrylate), poly(benzyl methacrylate), poly(2-ethylhexyl methacrylate), poly(glycidyl methacrylate), poly(hydroxybutyl methacrylate), poly(2- hydroxyethyl methacrylate), poly(hydroxypropyl methacrylate), poly(methyl

methacrylate), poly(phenyl methacrylate), poly(2-acrylamido-2-methyl-1 -propanesulfonic acid), poly(maleic acid), poly(maleic anhydride), polystyrene, polyvinyl acetate, poly(N- vinyl acetamide), poly(N-vinyl formamide), polyvinylpyridine, co-polymer thereof, or combination thereof.

[0109] 16. The composition of embodiment 15, wherein the at least one pH responsive polymer in the second coating layer is a vinylpyridine styrene co- polymer.

[0110] 17. The composition of any one of embodiments 1 to 16, wherein the second coating layer further comprises at least one hydrophobic polymer, at least one hydrophobic agent, or a combination thereof.

[0111 ] 18. The composition of embodiment 17, wherein the at least one hydrophobic polymer is a water-insoluble cellulose ether, poly(alkyl acrylate), poly(alkyl methacrylate), polyamide, polyimide, polybutadiene, polyisoprene, poly(alkylene succinate), polyalkylene terephthalate), polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl ether, polyvinyl ketone, polyvinyl pyridine, polyvinyl pyrrolidone, co-polymer thereof, or combination thereof; and the hydrophobic agent is a long chain fatty acid, a long chain fatty acid ester, a vegetable oil, a wax, or a

combination thereof.

[0112] 19. The composition of any one of embodiments 1 to 18, wherein the second coating layer comprises a vinylpyridine styrene co-polymer, a water- insoluble cellulose ether, and a long chain fatty acid.

[0113] 20. The composition of embodiment 19, wherein the second coating layer comprises about 5% to about 15% by weight of the composition.

[0114] 21. The composition of any one of embodiments 1 to 20, wherein the bioactive agent is lysine sulfate or lysine hydrochloride.

[0115] 22. The composition of embodiment 21 , which releases more than about 20% of free lysine in an aqueous medium having a pH of less than about 5.0. [0116] 23. The composition of embodiment 22, wherein more than about

30%, more than about 35%, more than about 40%, or more than about 45% of free lysine is released.

[0117] 24. A composition comprising (a) a core comprising lysine; (b) a first coating layer surrounding the core, the first coating layer comprising at least one polymer; and (c) a second coating layer surrounding the first coating layer, the second coating layer comprising at least one pH responsive polymer, wherein the composition releases more than about 20% of free lysine after rumen passage.

[0118] 25. The composition of embodiment 24, wherein the core comprises or consists of lysine hydrochloride or lysine sulfate.

[0119] 26. The composition of embodiments 24 or 25, wherein the irregularly-shaped core is devoid of binders, fillers, diluents, or combinations thereof.

[0120] 27. The composition of any one of embodiments 24 to 26, wherein the irregularly-shaped core has a diameter ranging from about 200 microns to about 3000 microns.

[0121 ] 28. The composition of any one of embodiments 24 to 27, wherein the irregularly-shaped core comprises a plurality of discrete particles of methionine adhering to its surface; or the irregularly-shaped core comprises a surface coating comprising methionine and at least one polymer.

[0122] 29. The composition of any one of embodiments 24 to 28, wherein that at least one polymer in the first coating layer is a water-soluble cellulose ether.

[0123] 30. The composition of embodiment 29, wherein the water-soluble cellulose ether is hydroxypropyl methyl cellulose or methyl cellulose.

[0124] 31. The composition of embodiments 29 or 30, wherein the first coating layer comprises about 5% to about 8% by weight of the composition.

[0125] 32. The composition of any one of embodiments 24 to 28, wherein the at least one polymer in the first coating layer is a vinylpyridine styrene co-polymer, and the first coating layer further comprises a long chain fatty acid. [0126] 33. The composition of embodiment 32, wherein the vinylpyridine styrene co-polymer is poly(2-vinylpyridine-co-styrene), and the long chain fatty acid is stearic acid.

[0127] 34. The composition of embodiments 32 or 33, wherein the first coating layer comprises about 10% to about 15% by weight of the composition.

[0128] 35. The composition of any one of embodiments 29 to 34, wherein the first coating layer further comprises a polymer of 2-hydroxy-4-methylthiobutanoate.

[0129] 36. The composition of any one of embodiments 24 to 35, wherein the at least one pH responsive polymer in the second coating layer is a vinylpyridine styrene co-polymer.

[0130] 37. The composition of embodiment 36, wherein the vinylpyridine styrene co-polymer is poly(2-vinylpyridine-co-styrene).

[0131 ] 38. The composition of any one of embodiments 26 to 37, wherein the second coating layer further comprises at least one hydrophobic polymer, at least one hydrophobic agent, or a combination thereof.

[0132] 39. The composition of embodiment 38, wherein the hydrophobic polymer is ethyl cellulose, and the hydrophobic agent is stearic acid.

[0133] 40. The composition of any one of embodiments 36 to 39, wherein the second coating layer comprises about 8% to about 12% by weight of the

composition.

[0134] 41. The composition of any one of embodiments 24 to 40, which release more than about 25%, more than about 30%, more than about 35%, more than about 40%, or more than about 45% of free lysine after rumen passage.

[0135] 42. A feed premix comprising the composition of any one of embodiments 1 to 41.

[0136] 43. A feed composition comprising at least one nutritive agent and the composition of any one of embodiments 1 to 41.

[0137] 44. A method for providing a bioactive agent to a subject, the method comprising administering the composition of any one of embodiments 1 to 41 , the feed premix of embodiment 42, or the feed composition of embodiment 43 to the subject.

[0138] 45. The method of embodiment 44, wherein the subject is a ruminant.

[0139] 46. A use of the composition of any one of embodiments 1 to 41 for providing a bioactive agent to a subject.

[0140] 47. The use of embodiment 46, wherein the subject is a ruminant.

[0141 ] 48. A composition of any one of embodiments 1 to 23 for use in the treatment of an amino acid deficiency, wherein the bioactive agent is an amino acid.

[0142] 49. A composition of any one of embodiments 24 to 41 for use in the treatment of a lysine deficiency.

EXAMPLES

[0143] The following examples describe various iterations of the claimed composition.

Example 1: Lysine Sulfate Core, HPMC Base Coat, and Top Coat

[0144] Lysine sulfate (350 g) was cleaned by soxhlet solvent extraction and allowed to dry completely. Alternatively, lysine sulfate was used directly as received from the manufacturer.

[0145] Hydroxypropylmethyl cellulose (HPMC) solutions were prepared by heating deionized water to 80°C, adding the appropriate amount HPMC, stirring until the solution was clear, and adjusting the final volume by adding cold deionized water. A 2% HPMC in water (800 mL) and a 6% HPMC in water (100 mL) base coating was applied to the granulated lysine sulfate cores (350 g) using a Wurster coating machine (Glatt, UniGlatt). The input air temperature of the coating machine was set to 93.3°C. The temperature was measured at 76.7°C input air and 38.8°C output air temperature at time zero for the coating process. The air speed was set to 2.0 bar, the fluid bed was set to 30 afu (air flow unit) and the coating solution pump rate was set to 10-12 mL per minute. The afu setting was set to maintain proper bed fluidization. The base coating process was performed over a period of 80 minutes. The final input air temperature was measured at 92.2°C and the output air was measured at 35.4°C. The final batch weight was 376 grams which correlated to a 6.9% HPMC base coating. An image of the HPMC base-coated lysine sulfate granules is presented in FIG. 1A.

[0146] The top coating layer was then applied to 300 grams of the HPMC coated lysine granules. To make the top coating solution, 120 rnl_ of acetone was combined with 120 ml_ of 200 proof ethanol. This solution was heated to 40°C. To this solution was added 22.4 g of stearic acid (SA), 5.4 g of poly-(2-vinylpyrdine-co-styrene) (P2VPS), and 1.11 g of ethyl cellulose (EC). This was stirred until a clear solution was obtained. This was applied to HPMC coated cores using a Wurster coating machine (Glatt, UniGlatt). The input air temperature of the coating machine was set to 40.6°C. The temperature was measured at 35°C input air and 28.7°C output air temperature at time zero for the coating process. The air speed was set to 2.0 bar, the fluid bed was set to 45 afu, and the coating solution pump rate was set to 12-15 ml_ per minute. The afu setting was set to maintain proper bed fluidization. The second coating process was performed over a period of 18 minutes. The final input air temperature was measured at 40.6°F and the output air was measured at 26.6°C. The final batch weight was 330 grams which correlated to a 9% top coating layer. FIG. 1B shows an image of the top- coated granules.

[0147] The pH dependent release of lysine was analyzed using a gravimetric in vitro bag test. For this, uncoated or coated particles were placed in a nylon bag which was then sealed with a zip-tie. Four separate bags were prepared for each formulation to be tested. The initial weight of each bag containing particles was measured. Each bag was place in a container filed with a simulated rumen fluid that was buffered to a different pH level (i.e. , 6.5, 5.5, 4.5, and 2.5). The containers (with the bags) were closed and placed inside a 40°C incubator oven, with constant shaking, for a period of 18 hours. After 18 hours, samples were removed from each container and the amount of lysine was measured using an HPLC method. The bags were dried and the final weight of each was measured. FIG. 2 presents the percent of lysine released at the various pH levels during this 18 hour period. The coated particles had >90% protection at pH 6.5, 5.5, and 4.5, but 100% release at pH 2.5.

Example 2: Lysine Sulfate Core, MC Base Coat, and Top Coat

[0148] Lysine sulfate was prepared as described above in Example 1. Methyl cellulose (MC) solutions were prepared by heating deionized water to 80°C, adding the appropriate amount MC, stirring until the solution was clear, and adjusting the final volume by adding cold deionized water. A 2.7% coating solution of MC was applied to the lysine sulfate core using a Wurster coating machine (Glatt, UniGlatt). The input air temperature of the Wurster coater was set to 93.3°C. The temperature was measured at 83.9°C input air and 52.5°C output air temperature at time zero for the coating process. The air speed was set to 2.0 bar, the fluid bed was set to 30 afu, and the coating solution pump rate was set to 6-9 mL per minute. The afu setting was set to maintain proper bed fluidization. The base coating process was performed over a period of 160 minutes. The final input air temperature was measured at 92.2°C and the output air was measured at 47.1 °C. The final batch weight was 375 grams which correlated to a 6.6% MC base coat. FIG. 3A presents an image of the MC base-coated lysine sulfate particles.

[0149] The top coating layer was then applied to 300 g of the MC coated lysine particles. The top coating solution (comprising SA, P2VPS, and EC) was prepared essentially as described above in Example 1. This coating was using a Wurster coating machine (Glatt, UniGlatt). The input air temperature of the Wurster coater was set to 37.8°C. The temperature was measured at 42.2°C input air and 34.5°C output air temperature at time zero for the coating process. The air speed was set to 2.0 bar, the fluid bed was set to 30 afu, and the coating solution pump rate was set to 12-15 mL per minute. The afu setting was set to maintain proper bed fluidization. The top coating process was performed over a period of 21 minutes. The final input air temperature was measured at 37.8°C and the output air was measured at 26.2°C. The final batch weight was 329 grams which correlated to an 8.8% top coat. An image of the top-coated particles is presented in FIG. 3B. [0150] The pH dependent release of lysine was measured using the in vitro bag test, which is described above in Example 1. FIG. 4 shows the release of lysine from the coated particles after 18 hrs at pH 2.5, but >80% protection at pH levels of 4.5, 5.5, and 6.5.

Example 3: Lysine HCI Core, SA/P2VPS Base Coat, and Top Coat

[0151 ] Lysine HCI (400 g) was weighed out and set aside for coating. A coating solution of 90% stearic acid and 10% P2VPS (poly-2 -vinylpyrdine-co-styrene) was prepared for coating directly on the lysine HCI cores. To make the coating solution, 315 mL of acetone was combined with 315 mL of reagent alcohol (or 200 proof ethanol). This solution was heated to 40°C. To this solution was added 59.4 g of stearic acid and 6.6 g of poly-(2-vinylpyrdine-co-styrene). This was stirred until a clear solution was obtained. This coating was applied to the lysine HCI cores using a Wurster coater machine (VFC-Lab mini, Freund Vector). The input air temperature of the

Wurster coater was set to 45°C. The temperature was measured at 43.6°C input air and 31 5°C output air temperature at time zero for the coating process. The air speed was set to 26.4 psi, the fluid bed was set to 13.0 cfrn, and the coating solution pump rate was set to 12 rpm. The cfrn setting was set to maintain proper bed fluidization.

The base coating process was performed over a period of 77 minutes. The final input air temperature was measured at 44.5°C and the output air was measured at 32.7°C. The final batch weight was 464 grams which correlated to a 13.8% base coat. FIG. 5A presents an image of the SA/P2VPS base-coated lysine HCI particles.

[0152] To make the top coating solution, 250 mL of acetone was combined with 250 mL of reagent alcohol (or 200 proof ethanol). This solution was heated to 40°C. To this solution was added 35.3 grams of stearic acid, 8.70 grams of poly-(2- vinylpyrdine-co-styrene), and 1.79 grams of ethyl cellulose. This was stirred until a clear solution was obtained. This coating was applied to 400 g of the SA/P2VPS base coated particles using a Wurster coater machine (VFC-Lab mini, Freund Vector). The input air temperature of the Wurster coater was set to 45°C. The temperature was measured at 44.2°C input air and 33.7°C output air temperature at time zero for the coating process. The air speed was set to 26.4 psi, fluid bed was set to 13.0 cfm, and the coating solution pump rate was set to 12 rpm. The cfm setting was set to maintain proper bed fluidization. The top coating process was performed over a period of 65 minutes. The final input air temperature was measured at 44.5°C and the output air was measured at 32.8°C. The final batch weight was 448 grams which correlated to a 10.7% top coat. FIG. 5B shows an image of the top-coated lysine HCI particles.

[0153] Lysine release was measured using the in vitro bag test, essentially as describe in Example 1. As shown in FIG. 6, after 18 hrs, the coated particles had >90% protection at pH 6.5, 5.5, and 4.5, but 100% release at pH 2.5.

Example 4: Lysine HCI Core, Methionine Undercoat, SA/P2VPS Base Coat, and Top Coat

[0154] Granular lysine HCI was coated with a solution of 1 % methionine and 1 % methyl cellulose MC), prior to application of base coat and top coat. For this, a 1 % solution of MC was prepared by heating 400 mL of deionized water to 80°C, adding 5.0 g of MC, and stirring 5 minutes. Then, ~50 mL of ice was added to the hot solution, which resulted in a clear MC solution. Once the MC solution had been cooled to ~

25°C, stirring is continued for a minimum of 30 minutes to ensure complete hydration.

As soon as the MC solution was fully hydrated, 5.0 g of dl-methionine was added and the solution was stirred. This coating solution was applied to 400 g of lysine HCL granules using a Wurster coating machine (VFC-Lab mini, Freund Vector) (NBP 88461 ). The input air temperature of the Wurster coater was set to 95°C. The temperature was measured at 92.5°C input air and 52.4°C output air temperature at time zero for the coating process. The air speed was set to 26.5 psi, the fluid bed was set to 12.0 cfm, and the coating solution pump rate was set to 9 rpm. The cfm setting was set to maintain proper bed fluidization. The coating process was performed over a period of 71 minutes. The final input air temperature was measured at 94.1 °C and the output air was measured at 46.8°C. The final batch weight was 409 grams which correlated to a 2.2% MC/methionine under coat. FIG. 7A shows an image of uncoated lysine HCI particles, and FIG. 7B shows an image of MC/methionine coated lysine HCI particles. [0155] The particles were then coated with a base coating solution of 90% stearic acid and 10% P2VPS. To make the coating solution, 315 ml_ of acetone was combined with 315 mL of reagent alcohol (or 200 proof ethanol). This solution was heated to 40°C. To this solution was added 59.4 g of SA and 6.6 g of P2PVS, and the solution was stirred until a clear solution was obtained. This coating was applied to 400 g of Met/MC coated lysine HCI particles using a Wurster coater machine (VFC-Lab mini, Freund Vector). The input air temperature of the Wurster coater was set to 45°C. The temperature was measured at 42.6°C input air and 30.7°C output air temperature at time zero for the coating process. The air speed was set to 26.4 psi, fluid bed was set to 12.0 cfm, and the coating solution pump rate was set to 12 rpm. The cfm setting was set to maintain proper bed fluidization. The coating process was performed over a period of 80 minutes. The final input air temperature was measured at 44.5°C and the output air was measured at 31.1 °C. The final batch weight was 465 grams which correlated to a 14.0% base coat. An image of the base-coated particles is presented in FIG. 7C.

[0156] The top coating solution was prepared by combining 250 mL of acetone with 250 mL of reagent alcohol (or 200 proof ethanol). This solution was heated to 40°C. To this solution was added 35.3 g of SA, 8.70 g of P2PVS, and 1.79 g of EC. This was stirred until a clear solution was obtained. This coating was applied to 400 g of base-coated particles using a Wurster coater machine (VFC-Lab mini, Freund Vector). The input air temperature of the Wurster coater was set to 45°C. The temperature was measured at 39.4°C input air and 27.2°C output air temperature at time zero for the coating process. The air speed was set to 26.4 psi, fluid bed was set to 12.0 cfm, and the coating solution pump rate was set to 12 rpm. The cfm setting was set to maintain proper bed fluidization. The coating process was performed over a period of 65 minutes. The final input air temperature was measured at 44.5°C and the output air was measured at 32.8°C. The final batch weight was 448 grams which correlated to a 10.7% top coat. FIG. 7D shows in image of the top-coated particles.

[0157] The pH dependent release of lysine was measured using the in vitro bag test, which is described above in Example 1. FIG. 8 shows nearly 100% release of lysine from the coated particles after 18 hrs at pH 2.5, but release of 15% of less at pH 4.5, 5.5, and 6.5.

Example 5: Two Coating Layers are Required for pH Dependent Release

[0158] Granular lysine sulfate or granular lysine HCI coated with a single coating (i.e. , base coating or top coating) does not provide rumen bypass protection (see the table below). The two coating layers are required for release at pH 2.5, but not at pH 4.5-6.5.