FIELD OF THE INVENTION
The present invention relates to a pharmaceutical composition in the form of a suspension and powder for suspension comprising Olmesartan or its pharmaceutical^ acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof. The invention also relates to process for the preparation of such compositions.
BACKGROUND OF THE INVENTION
Non-peptide angiotensin II receptor antagonists are used clinically as medicaments for the treatment and prophylaxis of hypertension. Angiotensin II receptor antagonists are particularly effective against renin-dependent hypertension. These agents are generally marketed as solid unit dosage forms such as tablets and capsules.
Olmesartan medoxomil, a widely used angiotensin II receptor antagonist, is marketed in the form of oral tablets under the trade name Benicar® in the US for the treatment of adult hypertension. However, these solid unit dosage forms are not suitable for administration to pediatrics and elderly who often have difficulty in swallowing and during emergency situations.
Olmesartan medoxomil is a BCS class II molecule. It suffers from the limitation of poor stability and aqueous solubility. It is insoluble in water which causes low rate of dissolution of the drug in aqueous media including biological fluids like gastrointestinal fluid. Olmesartan medoxomil is most stable in the pH range of 3 to 5. Under acidic or basic conditions and in the presence of water, it undergoes hydrolysis at the ester linkage to form Olmesartan acid (RNH-6270). Medicinal preparations comprising Olmesartan medoxomil are packaged in package containing metal oxides in order to reduce the smell arising out of the medicinal preparation. Thus, it is challenging for a formulation scientist to develop a dosage form of Olmesartan

medoxomil with technical attributes desirable for administration to pediatric and geriatric population.
Thus, there is an unmet need in the pharmaceutical art of dosage form of Olmesartan or its pharmaceutically acceptable esters, salts, solvates,polymorphs, enantiomers or mixtures thereof suitable for oral administration by pediatrics and geriatrics which also exhibits desirable pharmaceutical technical attributes such as pourability, viscosity, pH, dissolution, chemical stability and re-suspendability.
The present inventors have surprisingly developed a pharmaceutical composition in the form of a suspension comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof which exhibits desired pharmaceutical technical attributes.
OBJECTS AND SUMMARY OF THE INVENTION
An object of the present invention to provide a pharmaceutical composition in the form of a suspension comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof with one or more pharmaceutically acceptable excipient and/or carrier and process for their preparation.
It is another object of the present invention to provide an oral pharmaceutical composition in the form of a suspension a comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof with one or more pharmaceutically acceptable excipient and/or carrier like thickening agent, pH adjusting agents, coloring agent, sweetening agents, flavouring agent, coloring agent solubilizer / wetting agent, buffers, diluents, preservatives and stabilizer.

Another object of the present invention is to develop a suspension comprising Olmesartan or its pharmaceutical!;/ acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof by a manufacturing process which is consistent and therefore feasible for industrial production.
The following embodiments further describe the objects of the present invention in accordance with the best mode of practice, however, disclosed invention is not restricted to the particular embodiments hereinafter described.
Another object of the present invention, there is provided a suspension comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof and at least one or more pharmaceutically acceptable excipient and/or carrier including thickening agent, pH adjusting agent, coloring agent, sweetening agent, flavoring agent, coloring agent solubilizer / wetting agent, buffers, diluents, preservatives and stabilizer wherein, the suspension is stable to settling without sedimentation when stored undisturbed.
Another object of the present invention, there is provided a suspension comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof and at least one or more pharmaceutically acceptable excipient and/or carrier including thickening agent, pH adjusting agent, coloring agent, sweetening agent, flavoring agent, coloring agent solubilizer / wetting agent, buffers, diluents, preservatives and stabilizer wherein, the suspension is easily dispersible or resuspendible in a pharmaceutically acceptable liquid carrier such as purified water.
Another object of the present invention, there is provided a suspension comprising Olmesartan or its pharmaceutically acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof, wherein Olmesartan medoxomil has a particle size distribution D90 less than about 200 |j.m.

Another object of the present invention, there is provided a process for the preparation of a suspension comprising Olmesartan or its pharmaceutical^ acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof, wherein the Olmesartan medoxomil is coated to mask bitter taste of the drug.
Another object of the present invention, there is provided a suspension comprising Olmesartan or its pharmaceutical^ acceptable esters, salts, solvates, polymorphs, enantiomers or mixtures thereof in an amount of about 0.01% to about 90% by weight wherein, the composition is expected to exhibit desirable technical attributes like pourability, viscosity, dissolution, stability, re-suspendability, free from unpleasant odor.
Another object of the present invention, there is provided use of suspension comprising Olmesartan of the present invention in the manufacture of a medicament for treatment of hypertension.
Another object embodiment of the present invention, there is provided use of suspension comprising Olmesartan medoxomil of the present invention in the manufacture of a medicament for patients such as pediatric and geriatric who face difficulty in swallowing.
DETAILED DESCRIPTION OF THE INVENTION
The present invention can be more readily understood by reading the following detailed description of the invention and study of the included examples.
As used herein, the term "composition or "formulation" or "dosage form", as in pharmaceutical composition, is intended to encompass a drug product comprising an

Olmesartan or its pharmaceutical!)/ acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof, and other inert ingredient(s) (pharmaceutically acceptable excipients). Such pharmaceutical compositions are synonymous with "formulation" and "dosage form". Pharmaceutical composition of the invention include, but is not limited to suspension, a solution, a syrup, a concentrate, an elixir, or an emulsion. Preferably, the pharmaceutical composition of the invention is a suspension.
As used herein, the term "Suspension" is in the form of ready to use suspension/ pre-reconstituted suspension and powder for suspension (powder for reconstitution) / dry powder for suspension. The suspension powder for reconstitution comprises granules, pellets, or beads.
As used herein, the term " Olmesartan " is used in broad sense to include not only " Olmesartan " per se but also its pharmaceutically acceptable salts, esters, solvates, hydrates, enantiomers derivatives, polymorphs, prodrugs, analogs and also its various crystalline and amorphous forms that induce a desired pharmacological or physiological effect. Terms like "active", "active agent", "active substance" may be used synonymously for "active ingredient".
The term "excipient" means a pharmacologically inactive component such as a thickening agent/suspending agent viscosity agent, anticaking agent, antifoaming agent, pH adjusting agents, sweetening agents, flavoring agent, solubilizer / wetting agent, buffers, preservatives and antioxidant and the like. Co-processed excipients are also covered under the scope of present invention. Further, excipient may be in the form of powders or in the form of dispersion. Combination of excipients performing the same function may also be used to achieve desired formulation characteristics.
As used herein, the term "about" means ± approximately 20% of the indicated value, such that "about 10 percent" indicates approximately 08 to 12 percent.

As used in this specification, the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, a reference to "a process" includes one or more process, and/or steps of the type described herein and/or which will become apparent to those persons skilled in the art upon reading this disclosure and so forth.
Unless otherwise stated the weight percentages expressed herein are based on the final weight of the composition or formulation.
According to embodiment of the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutical^ acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more pharmaceutical^ acceptable excipients and/or a liquid carrier. .
According to another embodiment of the invention, the pharmaceutical^ acceptable excipient is selected from the group comprising one or more of thickening agent, anticaking agent, antifoaming agent, pH adjusting agent, sweetening agent, flavoring agent, solubilizer or wetting agent, buffer, antioxidant and preservative.
According to another embodiment of the invention, the pharmaceutically acceptable excipient is selected from the group comprising one or more of thickening agent, anticaking agent, antifoaming agent, pH adjusting agent, sweetening agent, flavoring agent, solubilizer or wetting agent, buffer, antioxidant and preservative and combinations thereof.
According to another embodiment of the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutical ly acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more

pharmaceutically acceptable excipients and/or a liquid carrier, wherein the thickening agent is selected from the group comprising gums, celluloses, a mixture of carboxymethylcellulose and microcrystalline cellulose, carbomers, polyvinyl alcohol, polyvinyl pyrrolidone, bentonite, cetostearyl alcohol, maltodextrin, and combinations thereof.
According to one embodiment of the present invention, the thickening agent is selected from the group comprising xanthan gum, a mixture of carboxymethylcellulose and microcrystalline cellulose and combinations thereof.
In another embodiment ,the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutically acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more pharmaceutically acceptable excipients and/or a liquid carrier, wherein the preservative is selected from the group comprising parabens, sorbic acid and its salts, benzoic acid and its salts such as sodium benzoate, sodium citrate, benzalkonium chloride, p-hydroxyl toluene (BHT), P-hydroxyl anisole (BHA), tocopherol and ethylenediamine tetraacetic acid and propyl gallate.
In another embodiment, the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutically acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more pharmaceutically acceptable excipients and/or a liquid carrier, wherein the antioxidant is selected from the group comprising ascorbic acid, sorbic acid, potassium sorbate, sodium pyrosulfite, glutathione, dibutylhydroxytoluene (BHT), hydroxylated anisole (BHA) and propyl gallate, tert-butylhydroquinone, sodium pyrosulfite, glutathione, sodium bisulfite, sodium sulfite, a-tocopherol, a-tocopherol acetate, monothioglycerol, cysteine, ascorbyl palmitate, acetylcysteine, dithiothreitol, sodium metabisulfite, thiourea, and sodium thiosulfate.

According to another embodiment of the invention, the pharmaceutically acceptable excipient is selected from the group comprising one or more of thickening agent, anticaking agent, antifoaming agent, pH adjusting agent, sweetening agent, flavoring agent, solubilizer or wetting agent, buffer, antioxidant and preservative and combinations thereof.
In another embodiment, the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutically acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more pharmaceutically acceptable excipients and/or a liquid carrier, wherein the sweetening agent is selected from the group comprising saccharin sodium, sorbitol solution, sucralose, sugar or a sugar substitute, sucrose, aspartame, fructose, mannitol and invert sugar.
In another embodiment, the present invention provides a liquid pharmaceutical composition of Olmesartan comprising Olmesartan or its pharmaceutically acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof and one or more pharmaceutically acceptable excipients and/or a liquid carrier, and a taste masking agent.
According to one embodiment of the invention, the taste masking agent is included in the composition as such or is used to coat the Olmesartan.
According to another embodiment of the invention, Olmesartan is in complex form with ion-exchange resin to mask the taste.
According to another embodiment of the invention the liquid carrier is selected from the group comprising aqueous and non-aqueous carrier optionally with one or more pharmaceutically acceptable excipients.

According to one embodiment of the invention, the aqueous carrier is selected from the group comprising water or a combination of water and a water-miscible organic solvent.
According to one embodiment of the invention, the non-aqueous carrier is selected from the group comprising oils e.g., peanut oil, soy bean oil, corn oil, sesame oil, cottonseed oil; mineral oil; fatty acid esters; mono- or di- fatty acid esters of polyethylene glycols; glyceryl mono-oleate; ethyl oleate; acetylated glycerides; or combinations thereof.
According to one embodiment of the invention, the composition is a suspension of Olmesartan.
According to one embodiment of this invention, the suspension is a ready to use suspension or powder for suspension.
According to another embodiment of this invention, the suspension is an aqueous suspension.
The pharmaceutical compositions of present invention comprise about 0.01% to about 80% by weight of Olmesartan, particularly in the range of about 0.01% to about 40% by weight on the basis of the total weight of the composition.
According to another embodiment of this invention, the amount of Olmesartan in the suspension ranges from about 0.01% to about 80% by weight on the basis of the total weight of the suspension. Particularly, the amount of Olmesartan in the suspension ranges from about 0.01 % to about 40%) by weight on the basis of the total weight of the suspension. More particularly, the amount of Olmesartan in the suspension ranges from about 0.01% to about 30% by weight on the basis of the total weight of the suspension.

According to another embodiment of the invention. Olmesartan has a particle size distribution D90 less than about 200 jam..
According to another embodiment of this invention, the amount of Olmesartan in the suspension ranges from about 0.1 mg/mL to about 100 mg/mL. The amount of Olmesartan in the suspension ranges particularly from about 0.5 mg/mL to 50 mg/mL, particularly from about 0.5 mg/mL to 20 mg/mL, particularly from about 0.5 mg/mL to 10 mg/mL..
According to another embodiment of the invention, the suspension has a pH in a range of3-8.
According to embodiment of the present invention provides a process for the preparation of a pharmaceutical composition of Olmesartan in the form of suspension and suspension powder for reconstitution comprising Olmesartan and one or more pharmaceutical^ acceptable excipients and/or a liquid carrier.
According to one embodiment of the invention, the process for the preparation of ready to use suspension comprises the following steps:
(i) dissolving/dispersing one or pharmaceutical ly acceptable excipients in a portion of water;
(ii) dispersing Olmesartan in the solution of step (i) to form a dispersion
(iii) mixing viscosity agent in another portion of water;
(iv) adding the mixture of step (iii) to the dispersion of step (ii); and
(v) optionally homogenizing the mixture of step (iv) to form a suspension.

According to another embodiment of the invention, the process for the preparation of the suspension powder for reconstitution comprises the following steps:
(i) mixing Olmesartan with one or more pharmaceutically acceptable excipients;
(ii) granulating the mixture of step (i) using a solvent;
(iii) drying the granulated mixture of step (ii);
(iv) milling the mixture of step (iii) to form granules; and
(v) mixing the granules of step (iv) optionally with one or pharmaceutical^ acceptable excipients to form the suspension powder for reconstitution.
The suspension powder for reconstitution is reconstituted with a liquid carrier such as water optionally comprising one or more pharmaceutically acceptable excipients at the time of first administration.
According to another embodiment of the present invention, the process for the preparation of the suspension powder for reconstitution comprises the following steps:
(i) mixing Olmesartan with one or more pharmaceutically acceptable excipients;
(ii) compacting the mixture of step (i) to form slugs
(iii) milling the slugs of step (ii) to form granules; and
(v) mixing the granules of step (iii) optionally with one or pharmaceutically acceptable excipients to form the suspension powder for reconstitution.
Powder/granules for oral suspension can be reconstituted using water or Powder/granules for oral suspension can be administered by sprinkling the powder/granules on one teaspoonful of applesauce or empty granules into a small cup or teaspoon containing one teaspoon of apple juice.

According to another embodiment of the present invention, the process for the preparation of the suspension powder for reconstitution comprises the following steps:
(i) mixing Olmesartan with one or more pharmaceutical!)/ acceptable excipients; and
(ii) optionally lubricating the mixture of step (i) to form the suspension powder for reconstitution.
The suspension powder for reconstitution can be reconstituted with a liquid carrier such as water optionally comprising one or more pharmaceutical^ acceptable excipients at the time of first administration.
According to another embodiment of the invention, the suspension powder for reconstitution can be prepared by blending, dry granulation, wet granulation and spheronization extrusion process.
In accordance with still another embodiment of the present invention, there is provided a process for the preparation of suspension comprising Olmesartan medoxomil, wherein the Olmesartan medoxomil is coated to mask bitter taste of the drug.
In accordance with still another embodiment of the present invention, there is provided a process for the preparation of a suspension of Olmesartan medoxomil comprising combining various components using conventional equipment such as an overhead stirrer, at about 100-500 rpm. Many different orders of adding components to the stirrer can be employed. This if followed by addition of liquid carrier (aqueous and/or non-aqueous), thickening/suspending agent, sweetening agent, taste masking agent and the like. pH of the suspension is adjusted to desired value using aqueous buffering agents as needed.
According to another embodiment of the present invention, the suspension can be packaged in a bottle.

According to another embodiment of the present invention, the suspension powder for reconstitution can be packaged in a bottle or a sachet.
According to another embodiment of the invention, the suspension after shaking does
not show sedimentation when stored undisturbed for at least 2 days at room
temperature.
According to another embodiment of the present invention, the composition is an
immediate release composition.
According to another embodiment of the invention, the composition is a stable composition.
The term "stable," as used herein, refers to chemical stability, wherein not more than 5% w/w of total related substances are formed on storage at 40°C and 75% relative humidity (R.H.) or at 25°C and 60% R.H. for a period of at least one month, particularly for a period of two months, and more particularly for a period of at least three months.
According to another embodiment of the invention, the composition further comprises one or more antihypertensive drugs, diuretics, NSAIDS and antibiotics.
According to another embodiment present invention provides a method of treating hypertension in a subject by administering a pharmaceutical composition of Olmesartan comprising Olmesartan and one or more pharmaceutically acceptable excipient and/or carrier.
According to another embodiment of the present invention provides a pharmaceutical composition of Olmesartan comprising Olmesartan and one or more pharmaceutically acceptable excipient and/or carrier for the treatment of hypertension.

In accordance with still another embodiment of the present invention, there is provided a suspension comprising Olmesartan medoxomil in an amount of about 0.01% to about 80% by weight wherein, the composition exhibits desirable chemical and physical properties, pourability, viscosity, dissolution, stability, and re-suspendability and a process for preparing the same.
In accordance with still another embodiment of the present invention, there is provided use of suspension comprising Olmesartan medoxomil of the present invention in the manufacture of a medicament for hypertension.
In another embodiment the liquid suspension formulation of the present invention includes particle size of Olmesartan medoxomil or its pharmaceutically acceptable salts, esters, solvates, polymorphs, enantiomers or mixtures thereof, having a particle size distribution such that D90 is less than about 200 ^im, D50 is less than about 100 (im and D10 is less than about 50 jam. The particle size of Olmesartan medoxomil can be measured by suitable techniques such as Laser light scattering (e.g. Malvern Light Scattering), Coulter counter, microscopy, Fraunhofer diffraction and any other technique known in the art. This particle size can be obtained either by the final step during the manufacture of the Olmesartan medoxomil or by the use of conventional micronizing techniques after the conventional crystallization procedure(s).
Carrier/solvents/vehicles used in the liquid suspension of the present invention include aqueous and non-aqueous carrier. These include but are not limited to water, vegetable oil, alcohol, polyethylene glycol, propylene glycol or glycerin buffers, or any combination thereof. Oils include peanut oil, soy bean oil, corn oil, sesame oil, cottonseed oil, acetylated glycerides, ethyl oleate, mineral oil, fatty acid esters, mono-or di- fatty acid esters of polyethylene glycols, or glyceryl mono-oleate. Preferably, the suspensions are aqueous based. By "aqueous carrier" is meant a suspension comprising water, or a combination of water and a water-miscible organic solvent or solvents.

Water-miscible solvents include but are not limited to propylene glycol, polyethylene glycol and ethanol. The carrier is present in an amount from about 35 w/w% to about 95 w/w%, particularly from about 45 w/w% to about 95 w/w%.
Various useful thickening agent/suspending agent include, but are not limited to, cellulosics such as hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC), methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethylcellulose, sodium carboxymethylcellulose, polyvinylpyrrolidone, hydroxypropylcellulose, hydroxypropylmethylcellulose, gums such as acacia, xanthan gum, guar gum, locust bean gum, gum tragacanth, carrageenan gum, and the like.alginic acid, alginate, sodium alginate, bentonite, carbomer, cetostearyl alcohol, maltodextrin, polyvinyl alcohol, polyvinyl pyrrolidone, propylene carbonate, propylene glycol, sodium starch glycolate, starch etc. The thickening/suspending agents are present in an amount of about 0.1% to about 10% w/w of the composition. More particularly, the thickening/suspending agents are present in an amount of about 0.1 % to about 5% w/w of the composition. Much more particularly, the thickening/suspending agents are present in an amount of about 0.1% to about 3% w/w of the composition.
The suspension has a viscosity in the range of 100 to 6000 cP at 25°C. Particularly, the viscosity is in the range of 100 to 2500 cP at 25°C. Viscosity can be measured by a suitable viscometer such as Brookfield viscometer at 25°C.
Surfactants or surface-active agents or wetting agents or antifoaming agent improve wettability of the dosage form and/or enhance its dissolution. These agents help in prevention of foam formation during high shear stirring and other manufacturing process. Few active ingredients are fluffy in nature and not suspend properly. Those type of active ingredients usually float on the surface of the vehicle/ solvent used in the suspension. Surfactants or surface-active agents or wetting agents or antifoaming agent

contemplated in the present invention include, but are not limited to, anionic surfactants, amphoteric surfactants, non-ionic surfactants and macromolecular surfactants. For example, polyethylene glycol stearates, poloxamer, polysorbates, sodium lauryl sulfate, dimethicone and simethicone, etc.
Anticaking agent helps to re-suspend the ingredients suspended in the formulation. Generally, suspension formulations contain micronized particles of active ingredients and inactive ingredients, which settle at the bottom of the container and form a thin hard cake, which is not easily re-suspend after shaking. Anticaking agent helps to improve the re-suspendability of the formulation. For example, colloidal silica and/ colloidal silicon dioxide or the like.
Various useful preservatives include, but are not limited to, parabens such as propylparaben, methylparaben, sorbic acid, benzoic acid and its salts such as sodium benzoate, sodium citrate, benzalkonium chloride, p-hydroxyl toluene (BHT), p-hydroxyl anisole (BHA), tocopherol, ethylenediamine tetraacetic acid. The preservative are present in an amount of about 0.005% w/w to about 3% w/w.
Various useful sweetening agents include, but are not limited to, saccharin sodium, sorbitol solution, sucralose, sugar or a sugar substitute, sucrose, aspartame, fructose, mannitol and invert sugar.
Various useful flavoring agents, include, but are not limited to, synthetic flavor oils and flavoring aromatics and/or natural oils, extracts from plant leaves, flowers, fruits, and so forth and combinations thereof. These may include cinnamon oil, oil of wintergreen, peppermint oils, clove oil, bay oil, anise oil, eucalyptus, thyme oil, cedar leaf oil, oil of nutmeg, oil of sage, oil of bitter almonds, and cassia oil. Also useful as flavors are vanilla, citrus oil, including lemon, orange, grape, lime and grapefruit, and fruit essence, including apple, banana, pear, peach, strawberry, raspberry, cherry, plum,

pineapple, apricot, maltol, ethyl vanillin, menthol, citric acid, fumaric acid, ethyl maltol, and tartaric acid.
Various useful isotonizing agent include, but are not limited to, sodium chloride, D-Mannitol, D-sorbitol, glucose, glycerin.
Various useful pH adjusting agent or buffering agents include, but are not limited to, gluconic acid, lactic acid, citric acid, acetic acid, sodium gluconate, sodium lactate, sodium citrate, sodium acetate potassium citrate, sodium bicarbonate, potassium bicarbonate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.
Various useful antioxidants include, but are not limited to, ascorbic acid, sorbic acid, potassium sorbate, sodium pyrosulfite, glutathione, dibutylhydroxytoluene (BHT), hydroxylated anisole (BHA) and propyl gallate, tert-butylhydroquinone, sodium pyrosulfite, glutathione, sodium bisulfite, sodium sulfite, a-tocopherol, a-tocopherol acetate, monothioglycerol, cysteine, ascorbyl palmitate, acetylcysteine, dithiothreitol, sodium metabisulfite, thiourea, and sodium thiosulfate.
Various useful taste masking agents include, but are not limited to, alkali metal chloride (e.g., sodium chloride, lithium chloride, or potassium chloride) or an alkaline earth metal chloride (e.g. magnesium chloride or calcium chloride) and polymers.
The compositions of the invention may also contain one or more active ingredients in addition to the Olmesartan medoxomil. The additional active ingredient may be another antihypertensive (such as Amlodipine), diuretic (such as Hydrochlorothiazide), or it may be an active ingredient having a different therapeutic activity like vitamins, antibiotics, NSAIDs and like.

Having described the invention with reference to certain preferred embodiments, other embodiments will become apparent to one skilled in the art from consideration of the specification. The invention is further defined by reference to the following examples describing in detail method for the preparation and testing of Olmesartan medoxomil pharmaceutical composition. It will be apparent to those skilled in the art that many modifications, both to materials and methods, may be practiced without departing from the scope of the invention. Following examples are set out to illustrate the invention and do not limit the scope of the present invention.
EXAMPLES
Ready to use suspension
Procedure:
1. Sucrose and sorbitol were added to a portion of pre- heated water to form a solution.
2. Olmesartan medoxomil was dispersed in the solution of step 1.

3. Xanthan gum and Avicel RC 591 were mixed in another portion of water and added to the dispersion of step 2.
4. Sodium saccharin, mono sodium dibasic phosphate, sodium benzoate, citric acid were added under stirring to the dispersion of step 3.
5. The dispersion of step 4 was homogenized and the volume is made up with the remaining quantity of water to form the suspension.
Example-3 Ready to use suspension
Procedure:
1. Olmesartan medoxomil, colloidal silicon dioxide and soyabean oil milled in a colloid mill.
2. Milling is continued and methyl paraben, propyl paraben, sucralose and propyl gallate are added. Then flavor (banana) is milled.
3. The milled suspension of step 2 is filtered.

Powder For Oral Suspension (Suspension powder for reconstitution)
Procedure:
1. Olmesartan medoxomil, monosodium dibasic phosphate anhydrous, sucrose, sorbitol powder, citric acid were mixed.
2. Sodium saccharin and sodium benzoate were dissolved in water.
3. The mixture of step 1 was granulated with solution of step 2.
4. The wet mass of step 3 was dried and milled to form granules.
5. Avicel RC 591, xanthan gum, banana flavor, cherry flavor were mixed and blended
with the granules of step 4 to form the suspension powder for reconstitution. The
Olmesartan suspension powder for reconstitution was reconstituted with water.

Assay for Olmesartan
The ready to use suspension of Example 2 and suspension powder for reconstitution of Example 5 after reconstitution were analyzed for drug content by HPLC as per USP 40 and the results are provided in Table 1.
Viscosity Data:
The viscosity of the reconstituted suspension of Example 2 and Example 5 was determined using Brookfield viscometer with spindle Sc4-18 and rpm 2 at 25°C.
pH data;
The pH of the reconstituted suspension of Example 2 and Example 5 was determined.
Table-1

We Claim:
1. An immediate release pharmaceutical suspension dosage form of Olmesartan or its pharmaceutically acceptable salt, hydrate or polymorph thereof comprising one or more pharmaceutically acceptable excipients.
2. An immediate release pharmaceutical suspension dosage form of Olmesartan or its pharmaceutically acceptable salt, hydrate or polymorph thereof comprising one or more pharmaceutically acceptable excipients wherein the pH of the composition is from 4- 8.
3. An immediate release pharmaceutical suspension dosage form of Olmesartan or its pharmaceutically acceptable salt, hydrate or polymorph thereof with one or more pharmaceutically acceptable excipients comprising Olmesartan from about 0.01% to about 80% by weight on the basis of the total weight of the composition wherein olmesartan particle size is D90 less than 200 |im.
4. An immediate release pharmaceutical suspension dosage form of Olmesartan or its
pharmaceutically acceptable salt, hydrate or polymorph thereof with one or more
pharmaceutically acceptable excipients comprising Olmesartan from about 0.01% to
about 80% by weight on the basis of the total weight of the composition wherein
olmesartan particle size is D90 less than 200 p.m. Wherein the pH of the composition
V is from 4- 8.
5. The pharmaceutical composition according to claims 1-4, wherein suspension is a
ready to use suspension or a suspension powder for reconstitution.
6. The pharmaceutical composition of claim 1-4, wherein the amount of Olmesartan
in the composition ranges from about 0.1 mg/mL to about 100 mg/mL.
7. The pharmaceutical composition according to claims 1-4, wherein the thickening
agent is selected from gums, celluloses, a mixture of carboxymethylcellulose and

microcrystalline cellulose, carbomer, polyvinyl alcohol and polyvinyl pyrrolidone, bentonite, carbomer, cetostearyl alcohol, maltodextrin, and combinations thereof.
8. The pharmaceutical composition of claim 1 -4, wherein the pH adjusting agent/buffer is selected from the group comprising gluconic acid, lactic acid, citric acid, acetic acid, sodium gluconate, sodium lactate, sodium citrate, sodium acetate potassium citrate, sodium bicarbonate, potassium bicarbonate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.
9. The pharmaceutical composition of claim 1-4, wherein the sweetening agent is selected from the group comprising saccharin sodium, sorbitol solution, sucralose, sugar or a sugar substitute, sucrose, aspartame, fructose, mannitol and invert sugar.
10. The pharmaceutical composition of claim 1-4, wherein the composition has
viscosity from 700-1100 cps.