COMPOSITIONS AND METHODS FOR TREATING HYPERTENSION USING

EPROSARTAN AND AMLODIPINE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is entitled to priority to U.S. Provisional Patent Application No. 61/388,092, filed September 30, 2010, which is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to compositions and methods for treating hypertension, particularly, to compositions and methods for treating hypertension using eprosartan and amlodipine.

BACKGROUND OF THE INVENTION

[0003] Hypertension is a public health problem that affects more than 25% of the adult population worldwide ^[1 ' ² Hypertension has been identified as the leading risk factor for mortality and as the third ranked factor for disability-adjusted life years ^[1 ' ^3] .

[0004] Despite the availability of numerous antihypertensive agents, the diagnosis, management, and control of hypertension are far from ideal, with control rates of 6% to 30% in different communities worldwide Nonadherence to antihypertensive treatment has been associated with lower rates of blood pressure (BP) control and higher rates of cardiovascular events ^[4"6] . Administration of a once-daily fixed-dose combination (FDC) therapy with 2 or more classes of antihypertensive agents is a strategy adopted for improving adherence and BP control. This strategy has been described in the 2003 World Health Organization (WHO)/International Society of Hypertension (ISH) guidelines, even as an initial therapeutic option ^[7 ' ^8] .

[0005] Calcium channel blockers (CCBs), a class of drugs or natural substances that disrupt the calcium (Ca ²⁺ ) conduction of calcium channels, are indicated as an initial therapy for hypertension. Their benefits and the possible risks have been explored in several clinical trials ^[9"14] . Use of high-dose CCBs has been associated with a high incidence of adverse events, such as peripheral edema and constipation ^[8 ' ^u ' ^12] . Amlodipine is a CCB with antihypertensive properties prescribed as monotherapy. It has been found to be well tolerated even in high-risk patients, such as those with coronary disease, heart failure, or multiple risk factors for cardiovascular events ^[12"16] . Amlodipine has a generally slower onset and longer duration of action than, for example, nifedipine ^[18] . The metabolites of amlodipine apparently do not possess significant calcium channel blocking activity, while the parent drug offers a biological half-life of some 35-40 hours, prompting a once-daily dosage regimen ^[19 ' ^20] . The ability of amlodipine to block calcium channels in smooth muscle produces peripheral vasodilation, which results in decreases in both systolic and diastolic blood pressure. The racemic mixture of amlodipine is presently used primarily as an antihypertensive agent, which produces peripheral vasodilation, resulting in decreases in both systolic and diastolic blood pressure when used as an antihypertensive agent. This antihypertensive effect occurs in the relative absence of significant or sustained effects on cardiac rate. However, the administration of the racemic mixture of amlodipine to a human has been found to cause adverse effects, such as increased heart rate, edema of the extremities, peripheral edema, headache, flushing/hot flashes, fatigue, vertigo, muscle cramps and dizziness.

[0006] Angiotensin II receptor antagonists, also known as angiotensin receptor blockers (ARB), ATi-receptor antagonists or saltans, have been primarily used for the treatment of hypertension where the patient is intolerant of angiotensin-converting enzyme (ACE) inhibitor therapy. They have also been used in treating diabetic nephropathy (kidney damage due to diabetes) and congestive heart failure. This class of drugs is usually well- tolerated. The question of whether or not angiotensin II receptor antagonists slightly increase the risk of heart attack (myocardial infarction) is currently being investigated.

[0007] U.S. Pat. No. 5,656,650 disclosed use of eprosartan, an angiotensin II receptor antagonist, and hydrocholothiazide (HCTZ), a first line diuretic drug of the thiazide class that acts by inhibiting the kidneys' ability to retain water, in a pharmaceutical composition for regulating hypertension, and treating congestive heart failure, renal failure, and glaucoma. A pharmaceutical composition having a combination of eprosartan, amlodipine and HCTZ is also disclosed in CN101690725 for treating cardiovascular diseases such as hypertension, corona heart disease and angina pectoris. However, there are potential complications associated with the use of diuretics or thiazide therapy ^[17] . [0008] There remains a need of novel effective and safe methods and pharmaceutical compositions for treating or preventing hypertension and related symptoms. Such methods and pharmaceutical compositions are described in the present application.

BRIEF SUMMARY OF THE INVENTION

[0009] It has been surprisingly discovered in embodiments of the present invention that eprosartan and amlodipine act synergistically in lowering the blood pressure in a subject suffering from hypertension, without causing significant or unacceptable adverse effects. The synergy between eprosartan and amlodipine is observed in the absence of HCTZ or any other diuretic drug of the thiazide class.

[0010] Accordingly, in one general aspect, embodiments of the present invention relate to a method of treating hypertension or a symptom associated therewith in a subject. The method comprises administering to the subject an effective amount of amlodipine and an effective amount of eprosartan, provided that the method does not further comprise administering to the subject an effective amount of a diuretic drug of the thiazide class, such as hydrochlorothiazide.

[0011] According to an embodiment of the present invention, the method comprises administering to the subject a pharmaceutical composition consisting essentially of an effective amount of amlodipine and an effective amount of eprosartan as the therapeutically active ingredients.

[0012] In another general aspect, embodiments of the present invention relate to a pharmaceutical composition for treating hypertension or a symptom associated therewith in a subject. The pharmaceutical composition comprises an effective amount of amlodipine and an effective amount of eprosartan, and a pharmaceutically acceptable carrier, provided that the pharmaceutical composition does not further comprise an effective amount of a diuretic drug of the thiazide class, such as hydrochlorothiazide.

[0013] According to an embodiment of the present invention, the pharmaceutical composition consists essentially of an effective amount of amlodipine and an effective amount of eprosartan as the therapeutically active ingredients.

[0014] Another general aspect of the present invention relates to a method of preparing a pharmaceutical composition for treating hypertension or a symptom associated therewith in a subject. The method comprises mixing an effective amount of amlodipine, an effective amount of eprosartan, and a pharmaceutically acceptable carrier in the pharmaceutical composition, provided that the method does not further comprise including an effective amount of a diuretic drug of the thiazide class in the pharmaceutical composition.

[0015] Embodiments of the present invention relate to the use of an effective amount of amlodipine and an effective amount of eprosartan for the manufacture of a medicament for treating hypertension or a symptom associated therewith in a subject, provided that the medicament does not further comprise an effective amount of a diuretic drug of the thiazide class.

[0016] According to an embodiment of the present invention, the administration of the effective amount of amlodipine and the effective amount of eprosartan, or the

administration of a pharmaceutical composition or a medicament according to the present invention, results in a synergistic effect in treating hypertension or the symptom in the subject.

[0017] Other aspects, features and advantages of the invention will be apparent from the following disclosure, including the detailed description of the invention and its preferred embodiments and the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

[0018] Various publications, articles and patents are cited or described in the background and throughout the specification; each of these references is herein

incorporated by reference in its entirety. Discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is for the purpose of providing context for the present invention. Such discussion is not an admission that any or all of these matters form part of the prior art with respect to any inventions disclosed or claimed.

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention pertains. Otherwise, certain terms used herein have the meanings as set in the specification. All patents, published patent applications and publications cited herein are incorporated by reference as if set forth fully herein. It must be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. [0020] As used herein, the name of a compound, such as eprosartan or amlodipine, can encompass all possibly existing isomeric forms (e.g., optical isomer, enantiomer,

diastereomer, racemate or racemic mixture), esters, prodrugs, metabolite forms,

pharmaceutically acceptable salts, pharmaceutically acceptable esters, pharmaceutically acceptable amides, and protected derivatives, of the compound.

[0021] The phrase "pharmaceutically acceptable salt(s)", as used herein, means those salts of a compound of interest that are safe and effective for pharmaceutical use in mammals and that possess the desired biological activity. Pharmaceutically acceptable salts include salts of acidic or basic groups present in the specified compounds. The acidic or basic groups can be organic or inorganic. Pharmaceutically acceptable acid addition salts include, but are not limited to, hydrochloride, hydrobromide, hydroiodide, nitrate, sulfate, bisulfate, phosphate, acid phosphate, isonicotinate, acetate, lactate, salicylate, citrate, tartrate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucaronate, saccharate, formate, benzoate, glutamate, methanesulfonate, ethanesulfonate, benzensulfonate, p-toluenesulfonate and pamoate (i.e., Ι, Γ-methylene-bis- (2-hydroxy-3-naphthoate)) salts. Suitable base salts include, but are not limited to, aluminum, calcium, lithium, magnesium, potassium, sodium, zinc, and diethanolamine salts. Certain compounds used in the present invention can form pharmaceutically acceptable salts with various amino acids, e.g., lysine, Ν,Ν'-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine (N-methylglucamine), procaine, and tris, and other salts which are currently in widespread pharmaceutical use and are listed in sources well known to those of skill in the art, such as The Merck Index. Any suitable constituent can be selected to make a salt of an active drug discussed herein, provided that it is non-toxic and does not substantially interfere with the desired activity. For a review on pharmaceutically acceptable salts, see [23], which is incorporated herein by reference.

[0022] As used herein, "eprosartan" or "E" refers to a compound having formula (I):

Formula (I)

and any pharmaceutically acceptable salts or pharmaceutically acceptable esters of the compound. For example, as used herein, the term "eprosartan" includes eprosartan mesylate, a salt of methanesulfonic acid (CH3SO3H). Eprosartan has been marketed for the treatment of high blood pressure, for example as Teveten® or Eprozar®, which contains eprosartan mesylate as the therapeutic agent. As with other angiotensin II receptor antagonists, eprosartan is generally better tolerated than ACE inhibitors, such as enalapril, especially among the elderly ^[21] .

[0023] The chemical synthesis of eprosartan can be performed using methods known in the art. See, e.g., U. S. Pat. No. 5, 185,351, the content of the reference is hereby incorporated by reference. It is also available from various commercial sources.

[0024] As used herein, "amlodipine", "AM" or "A" refers to a compound having formula (II):

Formula (II)

and any optical isomer, enantiomer, diastereomer, racemate or racemic mixture, pharmaceutically acceptable salts, or pharmaceutically acceptable esters, of the compound. For example, as used herein, the term "amlodipine" includes amlodipine in a

pharmaceutically acceptable salt form of inorganic and organic acids, such as besylate, hydrobromic, hydrochloric, phosphoric and sulfuric acids. See U. S. Pat. No. 4,806,557. As used herein, the term "amlodipine" also includes a pharmaceutically acceptable ester of amlodipine, particularly lower alkyl esters. Amlodipine has been marketed, for example, as NORVASC®, which contains amlodipine besylate, for the treatment of high blood pressure (hypertension), chest pain (angina) and other conditions caused by coronary artery disease.

[0025] Amlodipine is a chiral compound. A pharmaceutical composition according to embodiments of the present invention can comprise a racemate, i.e., 1 : 1 mixture of (R)-(+)- and (,S)-(-)-amlodipine or a racemic mixture of the (R)-(+)- and (,S)-(-)-amlodipine at different ratios. The pharmaceutical composition can also comprise isolated (R)-(+)- amlodipine or (S)-(-)-amlodipine that is substantially free of the other stereoisomer.

[0026] Preferably, a pharmaceutical composition according to embodiments of the present invention comprises substantially optically pure (S)-(-)-amlodipine or is substantially free of (R)-(+)-amlodipine.

[0027] As used herein, "substantially optically pure (S)-(-)-amlodipine" or

"substantially free of (R)-(+)- amlodipine" means that the pharmaceutical composition contains a greater proportion or percentage of (S)-(-)-amlodipine in relation to (R)-(+)- amlodipine. For example, the pharmaceutical composition preferably contains about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, by weight, of (S)-(-)- amlodipine, wherein the percentage is based on the total amount of (R)-(+)-amlodipine and (S)-(-)-amlodipine in the pharmaceutical composition.

[0028] The chemical synthesis of the racemic mixture of amlodipine can be performed using methods known in the art, e.g., as described in Arrowsmith, J. E. et al, ^[22 It is also available from various commercial sources. Separation of the amlodipine optical isomers from the racemic mixture can be performed by methods known in the art, such as those illustrated in U. S. Patent No. 6,448,275 or U. S. Patent No. 7,482,464. The contents of the references are hereby incorporated by reference.

[0029] As used herein, the term "pharmaceutical composition" is intended to encompass a product or composition comprising the specified ingredient in the specified amount, as well as any product which results, directly or indirectly, from combinations with the specified ingredient in the specified amount.

[0030] As used herein, the term "subject" means any animal, preferably a mammal, most preferably a human, to whom will be or has been administered compounds or pharmaceutical compositions according to embodiments of the invention. The term "mammal" as used herein, encompasses any mammal. Examples of mammals include, but are not limited to, cows, horses, sheep, pigs, cats, dogs, mice, rats, rabbits, guinea pigs, monkeys, humans etc., more preferably, a human. Preferably, a subject is in need of, or has been the object of observation or experiment of, treatment or prevention of hypertension and symptoms associated therewith.

[0031] As used herein, "treating hypertension or a symptom associated therewith" means to elicit an antihypertensive effect, such as by providing a normalization to otherwise elevated systolic and/or diastolic blood pressure, and by so doing providing relief from one or more possible symptoms or other hemodynamic effects caused by the elevated blood pressure.

[0032] In one embodiment, "treating" refers to an amelioration, prophylaxis, or reversal of a disease or disorder or at least one discernible symptom thereof, for example, treating hypertension or a symptom associated therewith by lowering the elevated systolic and/or diastolic blood pressure.

[0033] In another embodiment, "treating" refers to an amelioration, prophylaxis, or reversal of at least one measurable physical parameter related to the disease or disorder being treated, not necessarily the discernible symptom in or by the mammal, for example, treating hypertension or a symptom associated therewith by blocking voltage-gated calcium channels in cardiac muscle and/or by blocking the activation of angiotensin II ATi receptors.

[0034] In yet another embodiment, "treating" refers to inhibiting or slowing the progression of a disease or disorder, either physically, e.g., stabilization of a discernible symptom, or physiologically, e.g., stabilization of a physical parameter, or both.

[0035] In yet another embodiment, "treating" refers to delaying the onset of a disease or disorder or reducing the risk of acquiring a disease or disorder, such as hypertension or a symptom associated therewith. For example, the specified pharmaceutical compositions are administered as a preventative measure to a subject having a predisposition to hypertension, even though symptoms of hypertension are absent or minimal.

[0036] As used herein, the term "effective amount" of a compound refers to the amount of the compound to be used in a treatment, a pharmaceutical composition or a medicament that elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disease or disorder being treated. In a preferred embodiment, the effective amount of a compound is sufficient to treat, improve the treatment of, or prophylactically prevent, hypertension or a symptom associated therewith, but is insufficient to cause significant adverse effects associated with

administration of the compound.

[0037] Methods are known in the art for determining the effective amount of a therapeutically active ingredient according to embodiments of the present invention. As is understood by those of ordinary skill in the art, the dosage level will depend on the particular active ingredient used, e.g., its chemical and physical properties, mechanism of action, etc. Furthermore, and as is also understood by those of ordinary skill in the art, specific dose levels for any particular subject will depend upon a variety of factors including the age, body weight, general health, sex, diet, time of administration, route of administration, rate of excretion, any additional therapeutic agents administered in combination therewith and the severity of the disease or condition being treated. Generally speaking, the prophylactic or therapeutic treatment of the above identified conditions is expected to be achieved via administration of dosage levels of the active ingredients in amounts from about 0.01 mg/kg to about 100 mg/kg body weight per day, such as about 0.03 mg/kg to about 75 mg/kg body weight per day, about 0.05 mg/kg to about 50 mg/kg body weight per day, or about 0.1 mg/kg to about 10 mg/kg body weight per day. For example, the dosage levels of eprosartan, particularly eprosartan mesylate, can be about 0.5 mg/kg to 50 mg/kg body weight per day; and the dosage levels of amlodipine, particularly amlodipine besylate, can be about 0.01 mg/kg to 1 mg/kg body weight per day.

[0038] The desired or appropriate dosage level may be administered in a single daily dose, or the total daily dosage can be administered in divided doses of two, three or four times daily. Alternatively, the dosage can be formulated to be delivered in a substantially continuous fashion, as may be provided by sustained and/or controlled release dosage forms, or by a transdermal patch.

[0039] In a preferred embodiment of the present invention, the appropriate dosage level is administered in a single daily dose.

[0040] The term "adverse effect" includes, but is not limited to, any adverse or side effect associated with the use of eprosartan or amlodipine in a subject in need of the treatment, such as cardiovascular side effects (including tachycardia and diminished contractility of the heart), edema of the extremities, headache, dizziness, flushing, fatigue, vertigo, muscle cramps, hallucination, diarrhea, fever, urinary retention, vomiting, body rash/itching, etc.

[0041] According to embodiments of the present invention, eprosartan and amlodipine act synergistically in lowering the blood pressure in a subject suffering from hypertension, without causing significant or unacceptable adverse effects. The anti-hypertensive effect observed upon combined administration of eprosartan and amlodipine is greater than the sum of the individual anti-hypertensive effects observed upon the separate administration of eprosartan and amlodipine. This synergistic effect is obtained in the absence of HCTZ or any other diuretic drug of the thiazide class. Novel and improved pharmaceutical compositions and methods for treating hypertension or a symptom associated therewith are thus developed based on the combination of eprosartan and amlodipine in the absence of a diuretic drug of the thiazide class, such as HCTZ.

[0042] In one general aspect, embodiments of the present invention relate to a method of treating hypertension or a symptom associated therewith in a subject, comprising administering to the subject an effective amount of eprosartan and an effective amount of amlodipine, provided that the method does not further comprise administering to the subject an effective amount of a diuretic drug of the thiazide class, such as HCTZ.

[0043] Any of the pharmaceutically acceptable salts or pharmaceutically acceptable esters of eprosartan, such as eprosartan mesylate, can be used in the present invention.

[0044] Any of the optical isomer, enantiomer, diastereomer, racemate or racemic mixture, pharmaceutically acceptable salts, or pharmaceutically acceptable esters, of amlodipine, such as amlodipine besylate, can be used in the present invention.

[0045] In one embodiment, a racemic mixture of amlodipine or (R,S)-amlodipine, is used in the present invention.

[0046] In another embodiment, a substantially optically pure (S)-(-)-amlodipine, such as a substantially optically pure (S)-(-)-amlodipine besylate, (S)-(-)-amlodipine mesylate or S)-(-)-amlodipine maleate, is used in the present invention.

[0047] According to embodiments of the present invention, eprosartan and amlodipine can be administered together in the same pharmaceutical composition, or separately in different pharmaceutical compositions in any order, so long as the dosing schedules of eprosartan and amlodipine overlap in time. [0048] In one embodiment of the present invention, amlodipine and eprosartan are administered to the subject at a ratio of, for example, 1 :2000 to 1 : 1, such as 1 : 1000 to 1 : 10, by weight. Examples of such combinations include those wherein the ratio of amlodipine to eprosartan is 1 : 1, 1 :5; 1 :6.67; 1 : 10; 1 : 13.33; 1 :20; 1 :50; 1 : 100; 1 : 120; 1 :200; 1 : 1000 or 1 :2000, by weight.

[0049] In a preferred embodiment of the present invention, amlodipine besylate and eprosartan mesylate are administered to the subject at a ratio of about 1 : 120 to about 1 : 1, by weight, such as about 1 : 120, 1 : 100, 1 :75, 1 :50, 1 :25, 1 : 10, 1 :5, 1 : 1, etc., by weight.

[0050] According to an embodiment of the present invention, each of amlodipine and eprosartan is employed at an amount at or below which it exhibits an antihypertensive effect when used alone.

[0051] According to another embodiment of the present invention, the administration of the effective amount of amlodipine and the effective amount of eprosartan to a subject in need of the treatment results in a synergistic effect in treating hypertension or the symptom in the subject.

[0052] In one embodiment of the present invention, a suitable dose of amlodipine besylate for administration to a human for the treatment of hypertension can be in the range of 0.1 to 20 mg per day, such as 0.1 to 10 mg per day, 1 to 10 mg per day, etc. Amlodipine is preferably administered by an oral route once a day.

[0053] In another embodiment of the present invention, a suitable dose of eprosartan mesylate for administration to a human for the treatment of hypertension can be in the range of 10 to 2000 mg per day, such as 10 to 800 mg per day, 100 to 800 mg or 100 to 500 mg per day, etc. Eprosartan is preferably administered by oral route once a day.

[0054] In a preferred embodiment of the present invention, the method comprises orally administering to the subject about 1 to 10 mg/day amlodipine besylate and about 10 to 800 mg/day eprosartan mesylate.

[0055] According to an embodiment of the present invention, the method comprises administering to the subject a pharmaceutical composition consisting essentially of an effective amount of eprosartan and an effective amount of amlodipine as the therapeutically active ingredients.

[0056] Preferably, the method comprises administering to the subject an oral dosage form once daily, and the oral dosage form consists essentially of about 10 to 800 mg eprosartan mesylate and about 1 to 10 mg amlodipine besylate as the therapeutically active ingredients per dosage form.

[0057] In another embodiment of the present invention, the methods according to embodiments of the present invention comprise administering to the subject one or more additional therapeutically active ingredients, such as an additional antihypertensive agent, provided that the additional therapeutically active ingredient is not a diuretic drug of the thiazide class, such as HCTZ. The additional antihypertensive agent can be selected from the group consisting of β-adrenoceptor antagonists (β-blockers), ACE inhibitors, renin inhibitors, central sympatholytics, CCBs other than amlodipine and ARBs other than eprosartan. For example, one or more other CCBs or ARBs that are effective in lowering blood pressure in patients suffering from Coronary Artery Disease (CAD) can be used in combination with eprosartan and amlodipine. Eprosartan can reduce the increases in heart rates caused by amlodipine and the other CCBs.

[0058] Another general aspect of the present invention relates to a pharmaceutical composition for treating hypertension or a symptom associated therewith in a subject, which comprises an effective amount of eprosartan, an effective amount of amlodipine, and a pharmaceutically acceptable carrier, provided that the pharmaceutical composition does not comprise a diuretic drug of the thiazide class, such as HCTZ.

[0059] In one embodiment of the present invention, the pharmaceutical composition comprises amlodipine and eprosartan at a ratio of 1 :2000 to 1 : 1, preferably 1 : 120 to 1 : 1, by weight. Examples of such combinations include those wherein the ratio of amlodipine to eprosartan is 1 : 1; 1 :5; 1 :6.67; 1 : 10; 1 : 13.33; 1 :20; 1 :50; 1 : 100; 1 : 120; 1 :200; 1 : 1000 or 1 :2000, by weight.

[0060] In one embodiment of the present invention, the pharmaceutical composition comprises an oral dosage form for once daily administration to the subject. The oral dosage form comprises amlodipine besylate in the range of about 0.1 to 20 mg, preferably about 1 to 10 mg or about 1 to 5 mg, and eprosartan mesylate in the range of about 10 to 2000 mg, preferably about 10 to 800 mg, 100 to 800 mg, or about 100 to 500 mg, per dosage form.

[0061] In one embodiment of the present invention, the pharmaceutical composition consists essentially of an effective amount of eprosartan and an effective amount of amlodipine as the therapeutically active ingredients. Preferably, the pharmaceutical composition is an oral dosage form for once daily administration to the subject, which consists essentially of about 10 to 800 mg eprosartan mesylate and about 1 to 10 mg amlodipine besylate as the active ingredients per dosage form.

[0062] In another embodiment of the present invention, the pharmaceutical

compositions according to embodiments of the present invention comprise one or more additional therapeutically active ingredients, such as an additional antihypertensive agent, provided that the additional therapeutically active ingredient is not a diuretic drug of the thiazide class, such as HCTZ.

[0063] Whether administered alone or in combination with an additional

therapeutically active ingredient, the pharmaceutical composition according to

embodiments of the present invention can be administered by any known route of administration, including, orally, topically, parenterally (including subcutaneous, intravenous, intramuscular, and intrasternal injection or infusion administration techniques), by inhalation spray or rectally in dosage units or pharmaceutical compositions containing conventional pharmaceutically acceptable carriers and any such dosage units or

pharmaceutical compositions are within the scope of the present invention.

[0064] Pharmaceutical compositions adapted for oral administration include solid forms such as pills, tablets, caplets, and hard or soft capsules (each including immediate release, timed release, and sustained release formulations) as well as lozenges and dispersible powders or granules. Liquid forms of pharmaceutical compositions adapted for oral administration include solutions, syrups, elixirs, emulsions, and aqueous or oily suspensions. In view of the present disclosure, any of these dosage forms may be prepared according to any method or compounding technique known in the art for the manufacture of pharmaceutical compositions. The pharmaceutical compositions according to the invention can be prepared in a manner known per se and include those suitable for enteral, such as oral or rectal, and parenteral administration to mammals (warm-blooded animals), including human. The pharmaceutical compositions comprise an effective amount of the pharmacologically active compound, alone or in combination with one or more

pharmaceutically acceptable carriers, especially suitable for enteral or parenteral applications.

[0065] Pharmaceutically acceptable carriers that can be desirably utilized in the manufacture of solid oral dosage forms include inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating or disintegrating agents, such as corn starch or alginic acid; binding agents, such as starch, gelatin, or acacia; and lubricating agents such as magnesium stearate, stearic acid or talc. If desired, solid pharmaceutical compositions adapted for oral administration can further include one or more sweetening agents, flavoring agents, coloring agents, or preserving agents in order to provide attractive or palatable preparations.

[0066] In those embodiments wherein the dosage form is a tablet or pill, it can either be uncoated or coated, and if coated, can be coated by any known technique. Further, the coating, if desirably provided, can be formulated or applied by known techniques so that the coating can delay disintegration of the tablet or pill, and thus, absorption of the active ingredient, thereby providing a controlled and/or sustained release dosage form capable of providing sustained therapeutic or prophylactic effect over a longer period. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. An enteric layer that serves to resist disintegration in the stomach and permits the inner component to pass substantially intact into the duodenum or to be delayed in release can separate the two components. A variety of materials can be used for such enteric layers or coatings, including a number of polymeric acids, shellac, cetyl alcohol and cellulose acetate. Alternatively, in those embodiments wherein such a controlled and or sustained release is desired, tablets, pills or capsules may be formulated as osmotic pump dosage forms by any known method.

[0067] Pharmaceutical compositions adapted for oral administration can also be prepared as hard or soft gelatin capsules, wherein the active ingredient can be mixed with an inert solid diluent, such as calcium carbonate, calcium phosphate or kaolin in the case of the former or with water or miscible solvents such as propylene glycol, PEG's and ethanol, or an oil medium such as peanut oil, liquid paraffin, or olive oil in the case of the latter.

[0068] Aqueous suspensions can be prepared that contain the active ingredient(s) in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients include suspending agents, such as sodium carboxymethylcellulose,

methylcellulose, hydroxypropylmethylcellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia, dextran, polyvinyl-pyrrolidone or gelatin; and dispersing or wetting agents such as lecithin, polyoxy ethylene stearate, heptadecaethyleneoxycetanol, polyoxyethylene sorbitol monooleate, and polyethylene sorbitan monooleate. Aqueous suspensions can also contain one or more preservatives, such as ethyl or n-propyl, p- hydroxybenzoate; one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose, saccharine or aspartame.

[0069] Oily suspensions can be formulated by suspending the active ingredient(s) in a vegetable oil, such as cottonseed, olive, sesame or coconut oil, or in a mineral oil, such as liquid paraffin. The oily suspensions can contain a thickening agent, such as beeswax, hard paraffin, or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents can be added to provide a palatable oral preparation. Such oily suspensions can be preserved by the inclusion of an anti-oxidant such as ascorbic acid.

[0070] Dispersible powders and granules suitable for the preparation of an aqueous suspension suitable for oral administration can provide the active ingredient(s) in admixture with a dispersing or wetting agent, suspending agent, and one or more preservatives, all of which have been discussed above. Sweetening, flavoring, or coloring agents can also be present, if desired.

[0071] Pharmaceutical compositions suitable for oral administration can also be presented in the form of an oil-in- water emulsion. The oily phase can be a vegetable or mineral oil, such as those described above, or mixtures of these. Suitable emulsifying agents can be naturally-occurring phosphatides, such as soy bean, lecithin, sorbitan monooleate, or polyoxyethylene sorbitan monooleate. The emulsions can also contain sweetening or flavoring agents.

[0072] Syrups and elixirs can be formulated with sweetening agents, for example, glycerol, propylene glycol, sorbitol or sucrose. Such formulations can also contain a demulcent, a preservative and flavoring or coloring agents.

[0073] The pharmaceutical compositions can be further provided in a form adapted for parenteral administration, i.e., by injection or infusion. Injectable aqueous or oleaginous suspensions are desirably sterile and can be formulated according to known methods using suitable dispersing, wetting and suspending agents as described herein. A parenterally- acceptable diluent or solvent can also be utilized, such as 1,3-butanediol, water, Ringer's solution, and isotonic sodium chloride. Cosolvents such as ethanol, propylene glycol or polyethylene glycols can also be used. In addition, sterile, fixed oils are conventionally employed as solvents or suspending mediums in injectable or infusible solutions, and these may include any bland fixed oil, such as any of the synthetic mono- or diglycerides. Fatty acids such as oleic acid also can be utilized in the preparation of injectable or infusible solutions.

[0074] The pharmaceutical composition can also be presented in the form of a suppository. Suppositories can be formulated by mixing the active ingredient(s) and any additional desired therapeutic agent(s) with a suitable non-irritating excipient that is solid at room temperature but molten at body temperature, thereby releasing the active ingredient(s). Suitable materials include cocoa butter and polyethylene glycols.

[0075] For topical use, creams, ointments, gels, solutions or suspensions containing the active ingredient(s) may be prepared. As used herein, topical use includes mouth washes and gargles. Topical formulations can include cosolvents, emulsifiers, penetration enhancers, preservatives, emollients, and the like.

[0076] The therapeutically active ingredients according to embodiments of the present invention can also be provided in a pharmaceutical composition in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of lipids, including but not limited to amphipathic lipids such as phosphatidylcholines, sphingomyelins,

phosphatidylethanolamines, phophatidylcholines, cardiolipins, phosphatidylserines, phosphatidylglycerols, phosphatidic acids, phosphatidylinositols, diacyl

trimethylammonium propanes, diacyl dimethylammonium propanes, and stearylamine, neutral lipids such as triglycerides, and combinations thereof. They can either contain cholesterol or can be cholesterol-free.

[0077] Preferably, pharmaceutical compositions according to embodiments of the present invention are formulated for oral administration. The pharmaceutical compositions can be conveniently presented in dosage form, and prepared by any of the methods known in the art of pharmacy in view of the present disclosure. In general, the pharmaceutical compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation.

[0078] The corresponding therapeutically active ingredient or pharmaceutically acceptable salt thereof can also be used in form of a hydrate or include other solvents used for crystallization. The amount of therapeutically active ingredients to be included in a dosage form will depend upon the patient being treated, the mode of administration and the desired delivered dose.

[0079] In another embodiment of the present invention, each dosage form for oral administration, such as a pill, a tablet, a caplet, a hard or soft capsule, comprises a ratio of AM to eprosartan of 1 : 1 to 1 :2000, such as 1 : 1 to 1 : 120, by weight.

[0080] According to embodiments of the present invention, each dosage form for oral administration comprises AM and eprosartan at a ratio of, e.g., 1 : 1; 1 :5; 1:6.67; 1 : 10;

1 : 13.33; 1 :20; 1 :50; 1 : 100; 1 : 120; 1 :200; 1 : 1000 or 1 :2000, by weight.

[0081] In the case where an oral pharmaceutical composition is employed, a suitable dosage range of eprosartan for use in the present invention is from about 10 mg to about 2000 mg total daily dose, and a suitable dosage range of AM for use in the present invention is from about 0.1 mg to about 20 mg total daily dose, given as a once daily administration in the morning or in divided doses if required.

[0082] For example, for oral administration of eprosartan mesylate, a dose range of about 10 mg to about 1200 mg is given as a once daily administration or in divided doses if required, and preferably a dose range of about 10 mg to about 800 mg, about 100 mg to about 800 mg or about 100 mg to about 500 mg is given as a once daily administration or in divided doses if required. For oral administration of amlodipine besylate, a dose range of about 0.1 mg to about 20.0 mg is given as a once daily administration or in divided doses if required, and preferably a dose range of about 1 mg to about 10.0 mg or about 1 mg to about 5.0 mg is given as a once daily administration or in divided doses if required.

Patients can be upward titrated from below to within this dose range to a satisfactory control of symptoms or blood pressure as appropriate.

[0083] According to an embodiment of the present invention, the pharmaceutical composition is a once daily oral dosage form that comprises about 10 to about 800 mg eprosartan mesylate and about 1 mg to about 10.0 mg amlodipine besylate per dosage form.

[0084] This invention will be better understood by reference to the non-limiting example that follows, but those skilled in the art will readily appreciate that the example is only illustrative of the invention as described more fully in the claims which follow thereafter. Example

Animal Study on the Monotherapy and Combined Therapy of Eprosartan and Amlodipine

[0085] An in vivo study was conducted to measure and compare the anti-hypertensive efficacy and tolerability of eprosartan and amlodipine in monotherapy and combined therapy in spontaneous hypertensive rats, an animal model for hypertension.

[0086] Animals

[0087] All aspects of this study, including housing, experimentation and disposal of animals, were performed in general accordance with the Guide for the Care and Use of Laboratory Animals. Aged 18-week male normotensive Wistar Kyoto (WKY) and Wistar- Okamoto derived male spontaneously hypertensive rats (SHR) were used in this study.

[0088] Space allocation for 3 animals was 45 x 23 x 21 cm. Animals were housed in animal cages and maintained in a controlled temperature (20 - 24°C) and humidity (50% - 80%) environment with 12 hours light/dark cycles for at least three days. Unless animals were fasted for special purpose, free access to standard lab chow for rats [MF-18 (Oriental Yeast Co., Ltd., Japan)] and reverse osmosis (RO) water were granted.

[0089] Test Substances and Dosing Pattern

[0090] Amlodipine besylate (A) and eprosartan mesylate (E) were formulated in 1% methylcellulose and were administered orally at a dose level of 1 or 20 mg/kg alone or in combination. The dosing volume was 5 mL/kg.

[0091] Representative formulations are summarized in Table 1 below:

[0092] Table 1.

^(a) Based upon visual observation: S - soluble; I - insoluble (suspension or precipitation);

^(b) Formula was kept in tube or vial without protection from the light (N); and

^(c) Formula was prepared fresh and stored between 20-25°C.

[0093] Water for injection (WFI) (Tai-Yu, Taiwan) was used.

[0094] Study design [0095] The study design is shown in Table 2 below:

[0096] Table 2.

[0097] Equipments

[0098] Animal case (Allentown, USA), disposable syringe (1 and 3 mL, Terumo corporation, Japan), electronic scale (0-1000 g, Tanita Corporation, Japan), IITC Tail Cuff Model 229 (IITC, USA), MiniCollect Lithium Heparin Tube (Greiner Bio-One, Austria), and Needle for oral administration (Natsume, Japan) were used.

[0099] Measurements of Blood Pressure and Heart Rate

[00100] Test compounds, amlodipine besylate and eprosartan mesylate, were given orally to SHR rats (18 weeks of age) weighing 400 ± 100 g with an average systolic blood pressures of 200 ± 20 mmHg and heart rates of 400 ± 50 beats/min for confirmation of the efficacy of a treatment. Treatment with amlodipine besylate and eprosartan mesylate alone or amlodipine besylate in combination with eprosartan mesylate, were administered for 4 consecutive weeks by oral gavage. Blood pressure was recorded indirectly in a temperature controlled environment (34 ± 1°C) before (0 time) and 1 hour after test substance administration on days 1, 14 and 28. [00101] One-way ANOVA followed by Dunnett's test was applied for the comparison between vehicle control and test compound treated groups. P<0.05 is considered significant.

[00102] Biochemistry

[00103] Total cholesterol, LDL-cholesterol, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and Creatinine are measured by using automatic biochemical analyzers (Spotchem TM SP 4410 Kyoto Daiichi Kagaku Co. Ltd.).

[00104] Results

[00105] Table 3 shows the mean results measured from four animals. The decrease in systolic blood pressure (SBP) is expressed as the percentage of decrease in SBP compared to the pre-treatment SBP. Results shown in Table 3 illustrated that amlodipine besylate (A) administered alone at 1 mg/kg by oral gavage (p.o.) for consecutive 28 days did not result in a significant attenuation of the systolic blood pressure in SHR rats, when measured on days 1, 14 and 28. Eprosartan mesylate (E) administered alone at 20 mg/kg (E-high), but not at 1 mg/kg (E-low), resulted in a significant reduction of systolic blood pressure on days 1, 14 and 28. The combination of A (1 mg/kg) and E-low (1 mg/kg) resulted in a hypotensive effect that was more than the additive effects of the two treatments

administered alone, when measured on days 1, 14 and 28, indicating a synergistic effect throughout the 28 days of treatment. The combination of A (1 mg/kg) and E-high (20 mg/kg) also resulted in a hypotensive effect that was more than the additive effects of the two treatments administered alone, when measured on days 1 and 14, indicating a synergistic effect at least during the first 14 days of treatment.

[00106] Table 3.

Mean from 4 animals. [00107] Table 4 shows the mean results measured from four animals. The decrease in heart rate (HR) is expressed as the percentage of decrease in HR compared to the pre- treatment HR.

Results shown in Table 4 illustrated that amlodipine besylate (A) administered alone at 1 mg/kg by oral gavage (p.o.) for consecutive 28 days resulted in a slight increase in heart rate in SHR rats, when measured on days 1, 14 and 28. However, the increase in heart rate was generally not observed when A (1 mg/kg) was combined with E-low (1 mg/kg) or E- high (20 mg/kg), indicating that eprosartan can reduce the undesirable increase in heart rate caused by amlodipine.

Table 4.

Mean from 4 animals.

[00108] Results from the animal studies showed a synergistic effect of amlodipine and eprosartan in reducing systolic blood pressure in a hypertensive subject. The combination of eprosartan with amlodipine also reduced increases in heart rate caused by amlodipine, a side effect of amlodipine. These studies demonstrated that the combination of amlodipine and eprosartan provided a more effective and safer treatment of hypertension.

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