WIPE PRODUCTS HAVING ENHANCED LONG TERM STABILITY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of the filing date of U.S. provisional Patent Application No. 60/900,235, filed February 8, 2007.

FIELD OF THE INVENTION

[0002] The present invention relates to wipe products having an enhanced ability to maintain efficacy throughout the shelf life/expiration dating necessary for commercial products. More particularly, the present invention relates to wipes and packaging designs that impart wipe stability in packages containing a plurality of wipes per package.

BACKGROUND OF THE INVENTION

[0003] The explosive growth of wipes has been well documented by multiple market research organizations and periodicals. Once a market led by the simple baby wipe, the wipe industry has blossomed into a wide variety of wet, dry, and chemically-treated dry wipe products for industrial, household, and personal care applications.

[0004] As wipes are developed for sophisticated applications, care must be taken to ensure that the wipe maintains its efficacy over the expected, or required, shelf life of the product. In regulated products, such as prescription and over the counter (OTC) drugs, manufacturers are required to demonstrate that each wipe is stable, maintains efficacy, and does not vary in active drug content over the entire expected life of the wipe. The FDA has promulgated guidelines for the stability testing of drug products (ICH Guidelines). These guidelines are industry accepted methods for testing both real time stability and accelerated stability in order to define the shelf life and expiration date for OTC and prescription drug products.

[0005] It is known in the art that wipes packaging is required to protect the wipes from the environment, and from moisture and volatile material loss, over the life of the wipe. In some cases, ingredient loss from the package is addressed by overdosing a wet wipe with wipe ingredients, i.e., the wipe lotion, to compensate for ingredient loss during wipe shelf life. This approach is unacceptable for wipes containing a drug because the drug dosage must

be constant from wipe to wipe in a multiwipe package over time. Another approach has been to reduce the moisture transport properties (Moisture Vapor Transport Rate; MVTR) of the wipe packaging such that the package better retains volatile ingredients over the product shelf life.

[0006] In wipe packages containing more than one wipe, it is desired, or required, that all wipes in the package provide the designed, and a uniform, efficacy over the entire shelf life of the multiwipe product. For OTC and prescription drug products in wipe form, it is required that all the wipes in the package deliver the therapeutic benefit as described on the package labeling. The need to provide equivalent efficacy for all wipes in a package containing more than one wipe has been difficult, and has limited the commercialization of sophisticated products in multiwipe form.

SUMMARY QF THE INVENTION

[0007] The present invention is directed to wipes and packaging for a plurality of wipes that in combination help maintain the original constitution of a wipe lotion incorporated into a wipe. More particularly, the present invention relates to wipe lotions incorporated into a wipe substrate and to barrier packaging for a plurality of wipes. The combination of wipe lotion and barrier packaging maintain an essentially constant concentration of volatile and nonvolatile components of the wipe lotion in each wipe throughout the shelf life of the packaged wipes. The plurality of wipes can be packaged under reduced pressure, e.g., a vacuum, or at atmospheric pressure.

[0008] The improvement provided by the present invention is attained by a wipe and barrier package that promotes and maintains wipe lotion consistency across all wipes in a multiple package during the entire life of the product via a combination of the following:

[0009] a) a wipe lotion containing volatile and nonvolatile ingredients and having a rheology that helps prevent settling of the wipe lotion in the barrier package and that maintains an essentially constant concentration of active agents in each wipe throughout the life of the multiwipe product, and

[0010] b) wipe packaging for a stack of wipes having barrier properties and dimensions wherein a package width circumference ratio, as defined herein, is less than 3.35, preferably less than 3.25, less than 3, less than 2.75, or less than 2.5.

BRIEF DESCRIPTION OF THE FIGURES

[0011] Fig. 1 is a schematic showing a multiwipe package of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Barrier Packaging

[0012] Materials used in multipack wipe packaging are well known in the art, and often are multilayered plastic films designed to retain the liquid and volatile ingredients of a wipe lotion that are impregnated into the substrate of the wipe product. The packaging films typically contain one or more layer of materials designed to have low permeability to water, oxygen, and other liquid and gaseous compounds. These barrier layers reduce the migration or evaporation of critical wipe lotion ingredients from the package during the lifetime of the packaged wipes. The barrier packaging also can reduce the transport of volatile compounds throughout the wipes, i.e., between the individual wipes, that can cause undesirable composition changes by reacting with, or changing the concentration of, an ingredient of the wipe lotion.

[0013] Wipes that require barrier packaging contain water and/or other volatile ingredients as a component of the wipe lotion. If the vapor barrier of the packaging is insufficient, volatile ingredients transporting through the packaging can cause the wipes to "dry out" over time and before shelf life expiration of the multiwipe package. For an OTC or prescription drug product, water and/or volatile ingredient loss during the shelf life of the multiwipe package can result in an active drug concentration in a wipe that deviates from specifications for the wipe, which can adversely affect drug efficacy or safety and potentially can result in a product recall.

[0014] Adequate packaging barrier properties also are important for wipe products subjected to extreme conditions over time. Sufficient packaging barrier properties allow a prediction of stability over longer periods of time. Accelerated stability testing is common in cosmetic product development, and guidelines for such testing for drug products are known to persons known in the art are described in the International Conference on Harmonization Q 1 A (R2) Stability Testing of New Drug Substance and Products (February, 2003) (ICH Guidelines).

[0015] To achieve the benefits of the present invention, the moisture barrier property of the packaging film for multipack wipe products, as measured by Moisture Vapor Transport Rate, is less than about 1 gram/100 in ² /day, for example, less than about each of 0.95, 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, or 0.15 gram/100 in /day, at 25 ⁰ C, for water vapor. A preferred packaging film moisture barrier property is less than about 0.1, and more preferred less than about 0.05, gram/100 in /day at 25°C for water vapor.

[0016] In embodiments wherein the wipe multipack has a peel and reseal label over a die cut packaging film to allow an individual wipe to be removed from the multiwipe package, the moisture barrier properties of the label material also is important. In accordance with the present invention, the moisture barrier property of the peel/reseal label is less than about 1.5 gram/100 hr/day at 25 ⁰ C, for example, less than about each of 1.45, 1.4, 1.35, 1.3, 1.25, 1.2, or 1.15 gram/ 100 in /day for water vapor. A preferred water barrier property for a peel/reseal label is less than about 1, and more preferred less than about 0.5, gram/100 in ² /day at 25°C for water vapor.

Wipe Substrate

[0017] Wipes comprise a porous substrate having a wipe lotion impregnated therein. A wipe substrate utilized in the present invention is not limited, and can be any substrate known in the art of wipes.

[0018] A substrate of a wipe generally is an intersticed material, such as a cloth or fabric- like sheet, comprising fibers or fiber blends designed to impart desired strength and wetting properties to the substrate. A variety of substrate types and constructions are suitable for use in a wipe. Nonlimiting examples of suitable substrates include woven and nonwoven webs, such as spun-lace, melt-blown, and air-laid fabrics.

[0019] Cellulosic fibrous webs are preferred as the porous substrate because of a low cost and biodegradability. Other preferred porous substrates are paper, air-laid, and carded nonwoven webs. Spun-bonded and spun-lace webs also are suitable as the porous substrate. For applications where cost and/or biodegradability are not an issue, alveolar polymeric films, foam, and other porous substrates can be employed.

[0020] Nonfibrous substrates, such as foams or perforated films, also are envisioned as suitable wipe substrates. The substrate can be in the form of a sheet, pad, or applicator, for example. The substrate can be laminated with other materials, such as other fabrics or films, to achieve a desired form for application of the wipe lotion. The substrate can be wetted with aqueous or nonaqueous liquids, or can be dry, prior to loading with the wipe lotion.

Wipe Lotion

[0021] The composition impregnated into the substrate of a wipe is referred to as a "wipe lotion". Wipe lotions typically are liquids having dissolved and/or suspended ingredients that provide a desired benefit, i.e., contain volatile and nonvolatile ingredients. Wipe lotions can be water-based, oil-based, alcohol-based, or emulsions. Wipe lotions also can contain dispersed solids or microparticle delivery systems to provide a desired benefit. Wipe lotions often contain one or more prescription or OTC drug, in addition to other lotion ingredients.

[0022] Typically, the wipe lotion contains a volatile ingredient that evaporates when the wipe is applied to a target surface, thereby leaving the nonvolatile ingredients of the lotion on the target surface to perform their intended function. As used herein, a "target surface" is a surface contacted by a wipe to deliver a desired benefit. Nonlimiting examples of target surfaces include skin, teeth, and hair for cosmetic and drug applications, and hard surfaces, such as countertops, shower tile, glass, and food contact surfaces, for cleaning applications. For example, a sunscreen wipe is applied to the skin to transfer sunscreen actives to the skin. After the volatile ingredients evaporate, the nonvolatile sunscreen actives remain on the skin to impart UV protection to the skin.

[0023] Volatile ingredients include, but are not limited to, water; an alcohol, and typically a C ₁ , C ₂ , C _3; or C ₄ alcohol; a volatile silicone, typically a volatile dimethicone or volatile cyclomethicone; a volatile organic solvent, typically a hydrocarbon, a ketone, or an ester, such as acetone, methyl ethyl ketone, ethyl acetate, methyl acetate, isopropyl acetate, an isoparaffin, methylene chrloride, mineral spirits, pentane, toluene, or xylene; or any mixture of such volatile ingredients.

[0024] Wipe lotion rheology is important for a multipack wipe product to maintain a consistent lotion content in each wipe within the package. One failure mode for wipe products is gravity settling of the lotion to the bottom of the package during storage. This

results in wipes at the bottom of the package being overloaded with lotion, and accordingly, active agents, while wipes at the top of the package are depleted of lotion, e.g., depleted of active agents. Settling of the lotion can lead to individual wipes within the package failing to meet specifications with respect to active agent content.

[0025] It is known in the art to add components to wipe lotions to increase the viscosity of the lotion, and therefore minimize lotion settling through the wipe stack. For the purposes of this invention, any lotion-compatible, rheology-modifying compound can be incorporated into the wipe lotion in a amount sufficient to provide a rheology that prevents lotion settling due to gravity.

[0026] Another method of maintaining an essentially constant concentration of active agent, e.g., a drug, in each wipe of a multiwipe package is to incorporate the active agent into a microparticle delivery system. The microparticle delivery system is dispersed in the wipe lotion, as opposed to dissolved in the wipe lotion. Accordingly, even if the active agent is volatile, evaporation of the active agent from the microparticle delivery system, and accordingly, the wipe, is substantially reduced or eliminated.

[0027] Furthermore, because the microparticle delivery system is dispersed, as opposed to dissolved, in the wipe lotion, the microparticle delivery system resists settling from a wipe due to gravity. In particular, the microparticle delivery system, and any active agent loaded thereon, has a tendency to remain within the wipe substrate rather than separating from the substrate. The amount of active agent present in the wipe therefore remains essentially constant.

[0028] As used herein, the term "essentially constant" means that each wipe in a multiwipe package contains at least 90% and no more than 110%, by weight, of an active agent, non-active agent, or wipe lotion initially incorporated into the wipe. In preferred embodiments, each wipe contains at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, or at least 98%, of the active agent, non-active agent, or wipe lotion initially incorporated into the wipe. In other embodiments, each wipe contains no more than 109%, no more than 108%, no more than 107%, no more than 106%, no more than 105%, no more than 104%, no more than 103%, or no more than 102%, by weight of the active agent, non-active agent, or wipe lotion incorporated into the wipe.

[0029] In one embodiment, an active agent first is loaded onto a microparticle delivery system, then the loaded microparticle delivery system is incorporated into the wipe lotion. An active agent is incorporated, i.e., loaded, onto the polymeric microparticles by spraying or adding the active agent directly to the microparticles in a manner such that an essentially homogeneous distribution of the active agent is achieved on and/or through the microparticles.

[0030] If the active agent is a solid, the active agent can be dissolved in a suitable volatile solvent. The resulting solution is added to the microparticles, then the volatile solvent is removed, for example, under vacuum with gentle heating. Another method of loading of a solid active agent that is insufficiently soluble in an appropriate volatile solvent is to disperse the solid active agent in a suitable carrier, such as a polyol, then adding the dispersion directly to the microparticle delivery system.

[0031] Polymeric microparticle delivery systems comprise discrete, free-flowing particles which can absorb, adsorb, entrap, or otherwise retain an active agent in a polymeric matrix. Such microparticles can provide a controlled release of the active agent over time either by rupture of the microparticle, whereby the active agent is released when sufficient pressure or shearing action is applied to the microparticle, or the microparticle may be semipermeable or porous which allows the active agent to diffuse from the particle. In some embodiments, the polymeric microparticles themselves, without a loaded active agent, provide a desired benefit, i.e., an oil absorption function. Additionally, the microparticle delivery system can deliver multiple active agents in addition to itself.

[0032] The term "polymeric microparticle delivery system" encompasses microparticles and microcapsules generally, which are a well-known form of polymeric beads formed by emulsion polymerization, precipitation polymerization, and other methods. Absorbent polymeric microparticles have an ability to absorb several times their weight of a liquid compound, such as a skin care compound.

[0033] One preferred class of adsorbent polymeric microparticles useful as a delivery system is prepared by a suspension polymerization technique, as set forth in U.S. Patent Nos. 5,677,407; 5,712,358; 5,777,054; 5,830,967; and 5,834,577, each incorporated herein by reference. Such an absorbent polymer is sold under the tradename of POLY-PORE ^® E200

(INCI name: allyl methacrylate copolymer) available from AMCOL International Corporation, Arlington Heights, IL.

[0034] Another preferred class of adsorbent microparticles useful as a delivery system is prepared by a precipitation polymerization technique, as set forth in U.S. Patent Nos. 5,830,960; 5,837,790, 6,248,849; and 6,387,995, each incorporated herein by reference. Such an adsorbent polymer is sold under the tradename POLYTRAP ^® 7603 also available from AMCOL International Corp.

[0035] These adsorbent microparticles also can be modified after incorporation of an active agent to modify the rate of release of the active agent, as set forth in U.S. Patent No. 6,491,953, incorporated herein by reference.

[0036] Another useful class of adsorbent polymers prepared by a precipitation polymerization technique is disclosed in U.S. Patent Nos. 4,962,170; 4,948,818; and 4,962,133, each incorporated herein by reference, and are commercially available under the tradename of POLYTRAP ^® 6603, also available from AMCOL International Corp. Other useful, commercially available adsorbent polymers include, for example, MICROSPONGE ^® (a copolymer of methyl methacrylate and ethylene glycol dirnethacrylate), available from AMCOL International Corp., and PoIy-HIPE polymers (e.g., a copolymer of 2-ethylhexyl acrylate, styrene, and divinylbenzene) available from Biopore Corporation, Mountain View, California.

[0037] In particular, the adsorbent polymer microparticles prepared by the suspension polymerization technique, e.g., POLY-PORE ^® E200, are a highly porous and highly crosslinked polymer in the form of open (i.e., broken) spheres and sphere sections characterized by a mean unit particle size of about 0.5 to about 3,000 microns, preferably about 0.5 to about 300 microns, more preferably about 0.5 to about 100 microns, and most preferably about 0.5 to about 80 microns. A significant portion of the spheres is about 20 microns in diameter.

[0038] The polymeric microparticles are oil and water adsorbent, and have an extremely low bulk density of about 0.008 gm/cc to about 0.1 gm/cc, preferably about 0.009 gm/cc to about 0.07 gm/cc, and more preferably about 0.0095 gm/cc to about 0.04-0.05 gm/cc. The microparticles are capable of holding and releasing oleophilic (i.e., oil soluble or dispersible),

as well as hydrophilic (i.e., water soluble or dispersible), active agents, individually, or both oleophilic and hydrophilic compounds simultaneously.

[0039] Adsorbent polymer microparticles prepared by the suspension polymerization technique include at least two polyunsaturated monomers, preferably allyl methacrylate and an ethylene glycol dimethacrylate, and, optionally, monounsaturated monomers. The microparticles are characterized by being open to their interior, due either to particle fracture upon removal of a porogen after polymerization or to subsequent milling. The microparticles have a mean unit diameter of less than about 50 microns, preferably less than about 25 microns, and have a total adsorption capacity for organic liquids, e.g., mineral oil, that is at least about 72% by weight, preferably at least about 93% by weight, and an adsorption capacity for hydrophilic compounds and aqueous solutions of about 70% to about 89% by weight, preferably about 75% to about 89% by weight, calculated as weight of material adsorbed divided by total weight of material adsorbed plus dry weight of polymer, hi a preferred embodiment, the broken sphere microparticles are characterized by a mean unit diameter of about 1 to about 50 microns, more preferably of about 1 to about 25 microns, most preferably, of about 1 to about 20 microns.

[0040] Preferred polymeric microparticle delivery systems comprise a copolymer of allyl methacrylate and ethylene glycol dimethacrylate, a copolymer of ethylene glycol dimethacrylate and lauryl methacrylate, a copolymer of methyl methacrylate and ethylene glycol dimethacrylate, a copolymer of 2-ethylhexyl acrylate, styrene, and divinylbenzene, and mixtures thereof.

[0041] Specific polymeric microparticles useful in the present invention can be the previously described POLY-PORE ^® E200, POLYTRAP ^® 7603, POLYTRAP ^® 6603, MICROSPONGE ^® , or PoIy-HIPE particles, for example. An active agent is loaded onto such microparticles to provide microparticles containing about 10% to about 90%, preferably about 20% to about 80%, by weight, of the active agent. The active agent-loaded microparticles typically are incorporated into a wipe lotion in an amount to provide about 0.05% to about 10%, by weight, of an active agent in the composition.

[0042] To provide a delivery system for an active agent, the active agent is incorporated, or loaded, onto or into the microparticles. As used herein, the term "loaded microparticle"

refers to a microparticle having an active agent added thereto. Loading of the active ingredient includes one or more of impregnating, imbedding, entrapping, absorbing, and adsorbing of the active ingredient into or onto the polymeric microparticles. Loading of the active agent also can be referred to as an "entrapment." The term entrapment refers to a physical loading of the active ingredient onto the microparticles. Loading can be accomplished by spraying or adding the active agent directly to the microparticles in a manner such that a homogeneous distribution of the active agent on the microparticles is achieved. Alternatively, the active agent first can be dissolved in a suitable solvent, then the resulting solution is sprayed or added to the microparticles. The solvent then is removed by heating, vacuum, or both.

[0043] A wide variety of active agents can be loaded onto polymeric microparticles, and thereby included in a wipe of the present invention. These same active agents also can be incorporated into a wipe lotion in the absence of polymeric microparticles. Examples of active agents include, but are not limited to anti-acne agents, such as salicylic acid, benzoyl peroxide, sulfur, retinoic acid, and resorcinol; and skin-treatment agents, such as retinol, retinol palmitate, retinol acetate, dimethicone, petrolatum, hydroquinone, arbutin, ascorbic acid and derivatives thereof, tocopherol and derivatives thereof, dihydroxyacetone, and L- erythrulose.

[0044] More particularly, the active agent can be one of, or a mixture of, a cosmetic compound, a medicinally-active compound, or any other compound that is useful upon topical application to the skin. Such active agents include, but are not limited to, skin-care compounds, antioxidants, antibacterial compounds, antifungal compounds, anti- inflammatory compounds, topical anesthetics, sunscreens, insect repellants, skincare compounds, plant extracts, antioxidants, counterirritants, vitamins, steroids, and other cosmetic and medicinal topically effective compounds.

[0045] For example, if the composition is intended to be a sunscreen, then agents such as benzophenone-3, trihydroxycinnamic acid and salts, tannic acid, uric acids, quinine salts, dihydroxy naphtholic acid, an anthranilate, diethanol amine methoxycinnamate, p- aminobenzoic acid, phenylbenzimidazole sulfonic acid, PEG-25, p-aminobenzoic acid, or triethanolamine salicylate can be used as the active agent.

[0046] Further, sunscreen compounds, such as doxybenzone, ethyl 4- [bis(hydroxypropyl)] amino-benzoate, glyceryl aminobenzoate, homosalate, methyl anthranilate, octocrylene, octyl methoxycinnamate, octyl salicylate, oxybenzone, padimate O, red petrolatum, titanium dioxide, 4-menthyl-benzylidene camphor, benzophenone-1, benzophenone-2, benzophenone-6, benzophenone-12, isopropyl dibenzoyl methane, butyl methoxydibenzoylmethane, zotocrylene, zinc oxide, and mixtures thereof, can be used as the active agent.

[0047] Similarly, topically active drugs, like antifungal compounds, antibacterial compounds, antiinflammatory compounds, topical anesthetics, skin rash, skin disease, and dermatitis medications, and anti-itch and irritation-reducing compounds can be used as the active agent in the stick compositions of the present invention. For example, analgesics such as benzocaine, dyclonine hydrochloride, aloe vera, and the like; anesthetics such as butamben picrate, lidocaine hydrochloride, xylocaine, and the like; antibacterials and antiseptics, such as povidoneiodine, polymyxin b sulfate-bacitracin, zinc-neomycin sulfate-hydrocortisone, chloramphenicol, ethylbenzethonium chloride, erythromycin, and the like; antiparasitics, such as lindane; essentially all dermatologicals, like acne preparations, such as benzoyl peroxide, erythromycin benzoyl peroxide, clindamycin phosphate, 5,7-dichloro-8-hydroxyquinoline, and the like; anti-inflammatory agents, such as alclometasone dipropionate, beta-methasone valerate, and the like; burn relief ointments, such as o-amino-p- toluene- sulfonamide monoacetate, and the like; depigmenting agents, such as monobenzone; dermatitis relief agents, such as the active steroid amcinonide, diflorasone diactate, hydrocortisone, and the like; diaper rash relief agents, such as methylbenzethonium chloride, and the like; emollients and moisturizers, such as mineral oil, PEG-4 dilaurate, lanolin oil, petrolatum, mineral wax, and the like; fungicides, such as butocouazole nitrate, haloprogin, clotrimazole, and the like; herpes treatment drugs, such as O-[(2-hydroxymethyl)-methyl]guanine; pruritic medications, such as alclometasone dipropionate, betamethasone valerate, isopropyl myristate MSD, and the like; psoriasis, seborrhea, and scabicide agents, such as anthralin, methoxsalen, coal tar, and the like; steroids, such as 2-(acetyloxy)-9-fluoro-r,2',3',4'-tetrahydro-ll-hydroxypregn a- l,4-dieno-[16,17-b]naphthalene-3,20-dione and 21-chloro-9-fluoro-r,2',3',4'-tetrahydro-l Ib- hydroxypregna-l,4-dieno-[16,17-b]naphthalene-3,20-dione. Any other medication capable of topical administration, like skin bleaching agents, skin protectants, such as allantoin, and anti-

acne agents, such as salicylic acid, also can be incorporated into a wipe lotion in an amount sufficient to perform its intended function. Other topically active compounds are listed in Remington's Pharmaceutical Sciences, 17th Ed., Merck Publishing Co., Easton, PA (1985), pages 773-791 and pages 1054-1058 (hereinafter Remington's), incorporated herein by reference.

[0048] A skin conditioner can be the active agent of the wipe lotion. Skin conditioning agents include, but are not limited to, humectants, such a fructose, glucose, glycerin, propylene glycol, glycereth-26, mannitol, pyrrolidone carboxylic acid, hydrolyzed lecithin, coco-betaine, cysteine hydrochloride, glucamine, sodium gluconate, potassium aspartate, oleyl betaine, thiamine hydrochloride, sodium laureth sulfate, sodium hyaluronate, hydrolyzed proteins, hydrolyzed keratin, amino acids, amine oxides, water-soluble derivatives of vitamins A, E, and D, amino-functional silicones, ethoxylated glycerin, alpha- hydroxy acids and salts thereof, fatty oil derivatives, such as PEG-24 hydrogenated lanolin, beta-hydroxy acids and salts thereof (e.g., glycolic acid, lactic acid, and salicylic acid), and mixtures thereof. Numerous other skin conditioners and protectants are listed in the CTFA Cosmetic Ingredient Handbook, Eleventh Ed., T. Gottschalck et al., ed., The Cosmetic, Toiletry and Fragrance Association (2006), (hereafter CTFA Handbook), pages 2823-2850, incorporated herein by reference.

[0049] The skin conditioner also can be a water-insoluble ester having at least 10 carbon atoms, and preferably 10 to about 32 carbon atoms. Suitable esters include those comprising an aliphatic alcohol having about eight to about twenty carbon atoms and an aliphatic or aromatic carboxylic acid having from two to about twelve carbon atoms, or conversely, an aliphatic alcohol having two to about twelve carbon atoms with an aliphatic or aromatic carboxylic acid having about eight to about twenty carbon atoms. The ester is either straight- chained or branched. Suitable esters include, for example, but are not limited to:

[0050] (a) aliphatic monohydric alcohol esters, including, but not limited to: myristyl propionate, isopropyl isostearate, isopropyl myristate, isopropyl palmitate, cetyl acetate, cetyl propionate, cetyl stearate, isodecyl neopentanoate, cetyl octanoate, isocetyl stearate;

[0051] (b) aliphatic di- and tri-esters of polycarboxylic acid, including, but not limited to: diisopropyl adipate, diisostearyl fumarate, dioctyl adipate, and triisostearyl citrate;

[0052] (c) aliphatic polyhydric alcohol esters, including, but not limited to, propylene glycol dipelargonate;

[0053] (d) aliphatic esters of aromatic acids, including, but not limited to: C ₁₂ -C ₁₅ alcohol esters of benzoic acid, octyl salicylate, sucrose benzoate, and dioctyl phthalate. Numerous other esters are listed in the CTFA Handbook, at pages 2679 through 2688, incorporated herein by reference.

[0054] The topically- active agent also can be a plant extract or a natural oil. Nonlimiting plant extracts are those obtained from alfalfa, aloe vera, amla fruit, angelica root, anise seed, apple, apricot, artichoke leaf, asparagus root, banana, barberry, barley sprout, bee pollen, beet leaf, bilberry fruit, birch leaf, bitter melon, black currant leaf, black pepper, black walnut, blueberry, blackberry, burdock, carrot, cayenne, celery seed, cherry, chickwood, cola nut, corn silk, cranberry, dandelion root, elderberry, eucalyptus leaf, flax oil powder, ginger root, gingko leaf, ginseng, goldenrod, goldenseal, grape, grapefruit, guava, hibiscus, juniper, kiwi, kudzu, lemon, licorice root, lime, malt, marigold, myrrh, olive leaf, orange fruit, orange peel, oregano, papaya fruit, papaya leaf, passion fruit, peach, pear, pine bark, plum, pomegranate, prune, raspberry, rice bran, rhubarb root, rosemary leaf, sage leaf, spearmint leaf, St. John's wart, strawberry, sweet cloves, tangerine, violet herb, watercress, watermelon, willow bark, wintergreen leaf, witch hazel bark, yohimbe, and yucca root.

[0055] Other ingredients also can be incorporated into the wipe lotion and/or the polymeric microparticles. These ingredients include, but are not limited to, dyes, fragrances, preservatives, antioxidants, and similar types of compounds. These ingredients are included in an amount sufficient to perform their intended function, without adversely affecting the efficacy of an active agent present in the wipe lotion. It also is important that the concentration of such non-active agents remain essentially constant in each wipe in order to maintain the esthetics, and consumer acceptance, of the wipe.

Packaging Configuration

[0056] An important aspect of the present invention is the configuration of the barrier packaging over the stack of wipes. It has been discovered that the configuration of the barrier packaging is critical to maintaining a multiwipe product having an essentially consistant lotion loading in each wipe in the package, especially during storage. Package configuration

also contributes to maintaining a consistent balance between volatile and nonvolatile components of the wipe lotion within a wipe, and maintaining the desired or required concentration of wipe lotion components in each wipe.

[0057] Flexible "flow wrap" packaging is common in the industry to package a variety of wipe products. For the packaging of wet wipes, flow wrap packaging film is formed around a stack of wipes after the wipes have been dosed with the wipe lotion. The packaging is expected to maintain the wipe lotion within the package, thereby preventing ingredient loss via evaporation or leakage from the stack of wipes.

[0058] The packaging configuration typically is designed to allow a rapid and economical packaging of a wipe stack while avoiding the problem of a wipe being trapped or pinched in areas of the film that are heat sealed. As a result, the volume of the package typically is significantly larger than the volume of the packaged wipe stack, e.g., typically about three times the volume of the stack of wipes.

[0059] For the purposes of this invention, the relationship between the wipe stack size and the wrap package dimensions are as follows (Figure 1):

[0060] Wipe stack width circumference (WWC ) is the measure of the circumference around the width of the wipe stack, as measured by a flexible tape measure.

[0061] Wipe stack length circumference (WLC) is the measure of the circumference around the length of the wipe stack, as measured by a flexible tape measure.

[0062] Package length circumference (PLC) is the length of the packaging film surrounding the wipe stack in the length direction (L), neglecting sealed film areas.

[0063] Package width circumference (PWC) is the length of the packaging film surrounding the wipe stack in the width direction (W), neglecting the sealed film areas.

[0064] The width circumference ratio is 100(PWC-WWC)AVWC. [0065] The length circumference ratio is 100(PLC-WLC)/WLC.

[0066] Fig. 1 illustrates a barrier packaging film for a stack of wipes. In particular, Fig. 1 illustrates the back of packaging film 10 for a stack of wipes, wherein the film is wrapped around a stack of wipes (not shown) and sealed along a seam line 12 via a fin seal 16. The sealed package also is heat sealed at each end, denoted by heat seals 14. The length of the

packaging is denoted by the letter L, and is the measure of the package along seam 12. The width of the packaging is denoted by the letter W, and is the measure of the package perpendicular to seam line 12.

[0067] An example of wipe packages having a comparative configuration is described as follows. The wipe packages contained 10 sunscreen wipes sealed in flow wrap packaging with a peel/reseal label. The wipes were machine prepared individually by dosing a sunscreen lotion on each 8 x 8 inch substrate to a controlled amount. The wipes then were folded individually, assembled into a stack of 10 wipes, and packaged into flow wrap packages on a semi-automatic packaging machine. The packaging dimension relationships for the comparative packages (Packs 9-12) are summarized in Table IV.

[0068] The packages then were placed in a controlled environmental chamber at 45 ⁰ C for 93 days to simulate long term storage of the wipe package at room temperature. The wipe packages were oriented in the chamber with the peel/reseal label facing up and the wipes in the stack oriented horizontally allowing the wipes to be identified by their position in the wipe stack. After the prescribed time period, each package was removed from the chamber, and the wipes were removed from the package and weighed. The packages showed no indication of wipe lotion settling due to gravity because no free lotion was observed in the packaging. Evidence of moisture condensation occasionally was observed in some of the packages as tiny drops of water on the internal surfaces of the packaging film. The results of the experiment are summarized in Table I.

[0069] The results in Table I show that, contrary to expectations, the wipes at the top of the stack gained weight while the wipes at the bottom of the stack lost weight. In addition, chemical analysis for an active agent contained in the lotion (i.e., benzophenone 3) demonstrated a reduced active content in the wipes that gained weight. The wipes that lost weight showed an increase in active agent concentration. This event is unexpected because the lotion is expected to settle within the wipe stack.

[0070] This effect also is apparent in commercial wipe packages stored at room temperature (Table II). The data in Table II shows that two commercial wipe packages also exhibited an unexpected weight change effect at room temperature. This effect is a significant problem in the production of wipes because variations in weight and active agent

concentration can cause the wipes to vary from specification or exhibit poor efficacy in their desired application. For OTC and prescription drug wipes, the changes can lead to the multiwipe package containing wipes that fail to meet specifications and, potentially, differences in wipe performance as a function of wipe location in a stack.

[0071] One hypothesis for of this effect, without being bound to any theory, is that the package configuration, if outside the design specifications disclosed herein, can result in a migration of wipe lotion volatiles within the package. This migration is a result of a "headspace" effect in the unoccupied volume in the package. Volatiles in the wipe lotion, such as water or alcohols, can evaporate from the stack within the package. This vapor then can condense, for example, on the interior surfaces of the package as droplets of liquid. The liquid droplets then can drip from the inner surfaces of the packaging onto the wipes. This effect can result in a dilution of wipe lotion at the top of the stack, and a change in the concentration of nonvolatile components of the wipe lotion in other zones of the wipe stack, as illustrated in the data in Table I. The nonvolatile components of the lotion in the wipes, e.g., topically applied drugs and sunscreen agents, do not migrate from their location in the wipe stack because the rheology of the lotion prevents lotion settling or other movement.

[0072] For the purposes of present invention, it has been discovered that this effect can be minimized or eliminated by a proper relationship between the dimensions of the wipe stack and the dimensions of the wipe barrier packaging. A multiple package of the present invention can be prepared at atmospheric pressure or at a reduced pressure, e.g., under a vaccum.

[0073] As used herein, "atmospheric pressure" is the pressure exerted by the atmosphere alone at the temperature of manufacture for the multiwipe packet, i.e., without an application of additional pressure or a reduction in atmospheric pressure. The term "a vacuum" or "at reduced pressure" means any pressure that is less than atmospheric pressure at the temperature of manufacture for the multiwipe packet.

Example

[0074] In order to demonstrate the present invention, sunscreen wipes were prepared and packaged in flow wrap film under vacuum to reduce the headspace in the package to essentially zero. The packages then were placed in an environmental chamber at 50 ⁰ C for 14

days to simulate a long term storage of the wipes packages at room temperature. The packages were removed from the chamber, opened, and the wipes were weighed. This weight was compared to their initial weights. The data from this example is summarized in Table III.

[0075] The data in Table III shows that when the headspace is reduced to essentially zero, the migration of volatiles in the wipe stack also is greatly reduced. Because the elimination of headspace in flow wrap packaging is difficult to achieve in practice, an experiment was performed to determine the effect of headspace reduction on improvement in wipe stability, as measured by a reduction in volatiles migration.

[0076] In this respect, a wipe package was prepared (i.e., AMCOL HBS SPF 30 Sunscreen wipes) using production converting and packaging equipment. The relationship between the wipe stack dimensions and the packaging film dimensions is summarized in Table IV. The wipes package was placed in a controlled environment chamber for 3 months at 45 ⁰ C to simulate extended storage at room temperature. The wipes package then was removed from the chamber, opened, and the wipes in the stack were weighed to determine the effect of volatiles migration on the wipe weights. The results are summarized in Table V. The results show that moisture migration is greatly reduced compared to the comparative samples in Tables I and II.

[0077] Overall, the results show that a reduction in the width circumference ratio has the greatest effect in reducing moisture migration within the wipe stack.

Table I

OO

Starting Wipe Weight = 10.7 grams

Starting Benzophenone 3 Active Weight in Wipe Lotion = 3.04%

Table II

Table III

o

Table IV

K ⁾

Table V

[0078] The multiwipe packages of the present invention have several practical end uses, including hand cleansers, surgical scrubs, body splashes, antiseptics, disinfectants, hand sanitizer gels, and similar personal care products. The wipes further can be used on inanimate surfaces, for example, sinks and countertops in hospitals, cruise ships, nursing homes, food service areas, and meat processing plants.

[0079] In particular embodiments, the wipes can be designed as lotions; makeup preparations, like makeup foundations; skin care preparations, like hand lotions, vanishing creams, night creams, sunscreens, body lotions, facial creams, clay masks, moisturizing lotions, makeup removers, antiacne preparations, antiaging preparations, and sebum control preparations; analgesic and cortisonal steroid creams and preparations; insect repellants; and facial masks and revitalizers.

[0080] The wipes also can be useful to treat hard surfaces. As used herein with respect to the surfaces treated by the present wipes, the term "hard" refers to surfaces comprising refractory materials, such as glazed and unglazed tile, brick, porcelain, ceramics, metals, glass, and the like, and also includes wood and hard plastics such as formica, polystyrenes, vinyls, acrylics, polyesters, and the like. Such surfaces are found, for example, in kitchens and bathrooms. A hard surface can be porous or nonporous.

[0081] The wipes also can be used to treat hard surfaces in processing facilities (such as dairy, brewing, and food processing facilities), healthcare facilities (such as hospitals, clinics, surgical centers, dental offices, and laboratories), long-term healthcare facilities (such as nursing homes), farms, cruise ships, schools, and private homes.

[0082] The wipes can be used to treat environmental surfaces such as floors, walls, ceilings, and drains. The article can be used to treat equipment such as food processing equipment, dairy processing equipment, brewery equipment, and the like. The wipes can be used to treat a variety of surfaces including food contact surfaces in food, dairy, and brewing facilities, countertops, furniture, sinks, and the like. The wipes further can be used to treat tools and instruments, such as medical tools and instruments, dental tools and instruments, as well as equipment used in the healthcare industries and institutional kitchens, including knives, wares (such as pots, pans, and dishes), cutting equipment, and the like. Methods of treating hard surfaces are described in U.S. Patent Nos. 5,200,189; 5,314,687; and 5,718,910, the disclosures of which are incorporated herein by reference in their entirety.

[0083] Treatable inanimate surfaces include, but are not limited to, exposed environmental surfaces, such as tables, floors, walls; kitchenwares, including pots, pans, knives, forks, spoons, and plates; food cooking and preparation surfaces, including dishes; food preparation equipment; and tanks, vats, lines, pumps, hoses, and other process equipment. One useful application of the present wipes is to contact dairy processing equipment, which is commonly made from glass or stainless steel. Such equipment can be found both in dairy farm installations and in dairy plant installations for the processing of milk, cheese, ice cream, and other dairy products.

[0084] The wipes also can be used to treat medical carts, medical cages, and other medical instruments, devices, and equipment. Examples of medical apparatus treatable by the present wipes are disclosed in U.S. Patent No. 6,632,291, incorporated herein by reference.

[0085] Obviously, many modifications and variations of the invention as hereinbefore set forth can be made without department from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.