WO2008074108A2

WO2008074108A2 - Controlled release pharmaceutical composition of anti-hyperglycemic agent and its preparation

Info

Publication number: WO2008074108A2
Application number: PCT/BR2007/000331
Authority: WO
Original assignee: Medley S.A. Indústria Farmacêutica
Priority date: 2006-12-20
Filing date: 2007-12-05
Publication date: 2008-06-26
Also published as: BRPI0605967A; CL2007003675A1; WO2008074108A3

Abstract

The composition, pharmaceutical form and processes in the present invention comprise a nucleus obtained by compression, having bioadherent property and gastric retention capacity, containing extended release, water-soluble anti-glucose-providing agent, also soluble in pH lower or equal to 5, having as controlled release regulating agent benzene-free polymerized polyacrylic acid or its derivatives. The nucleus may contain one or more acid-modulated coating layers with coadjuvant pharmacologically active agents, also having anti-glucose-providing effect, non-water-soluble and soluble in pH higher or equal to 5, immediate release, also comprising pharmaceutically acceptable excipients. The bioadherent nucleus allows controlled release of biguanides, preferably metformin and the coating layers allow sulphonylureas release, preferably glimepiride. The present invention allows isolated metformin release or combined release of two classes of drugs with different solubility and absorption conditions, and the volume of their final form is reduced.

Description

CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION, CONTROLLED RELEASE PHARMACEUTICAL FORM AND PROCESS FOR OBTAINING PHARMACEUTICAL FORM

The present invention relates to a pharmaceutical composition, pharmaceutical form, as well as the process for obtaining it, for pharmaceutical industry application, particularly for medications containing anti-hyperglycemic agents required for treating diabetes or related dysfunctions. Metformin is an anti-hyperglycemic agent included in the biguanides class, used for treating non-insulin-dependent diabetes mellitus, i.e., type Il diabetes. Metformin hydrochloride shows low mean permeability in gastrointestinal tract, and is essentially absorbed on the intestine proximal area, i.e., in the duodenum, with low absorption in further intestinal areas. Metformin is highly water-soluble, over 300 mg/ml, and in immediate release compositions, it may show concentration peaks, having maximum concentration values (C_max) in short maximum concentration times (T_max).

Both factors lead to great difficulty in formulating modified release tablets, as the release within times longer than 60 minutes may change the average bioavailability level, in keeping with the dynamic change in the absorption site, along the gastrointestinal tract, as the pharmaceutical form has little time of residence in the area with higher metformin absorption, i.e., the duodenal tract. The use of modified release pharmaceutical forms for metformin release, if not appropriately controlled, may lead to sub-optimal, or even ineffective, metformin plasma levels. The modified release metformin tablets, i.e., the ones with release conditions different from the drug inherent solubility, shall also go beyond the high solubility barrier of the active ingredient, i.e., the metformin, as it is difficult for the systems that use the drug diffusion processes to the external medium to keep the flow constant, or also, therapeutically effective, for several hours. Additionally, for highly soluble drugs, the diffusion matrix requires large amounts of insoluble products, both inside the matrix and on the coating films. As the usual metformin dose is relatively large, from about 500 to 1250 milligrams of active ingredient per tablet, the final average volume and weight of tablets usually become impracticable for ingestion. Even with insoluble polymers as main excipients for slow-release tablets, it is very difficult to control the mass active release at the first post-ingestion moments. The so-called burst effect, namely, large release within a short period of time, is common in highly soluble drugs, and shall be avoided, as it may lead to high concentration of active ingredients in the blood stream. Thus, the dissolution profile, i.e., the design of active ingredient accumulated percentage vs. time shall present a characteristic curve of modified release pharmaceutical forms.

Therefore, an effective formulation for modified release, namely, a release supported for up to 18 hours shall provide the maintenance of a release curve from 0 to 18 hours with no release peaks (burst).

Document US 6475521 corresponding to document BR 9908911 by Timmins et al. teaches that a controlled release biphasic formulation may control metformin release using HPMC (hydroxypropylmethylcellulose) as the main component, by using the gastric retention principle by volume.

This solution is marketed in Brazilian market under the trade name Glifage

XR (Glucophage XR in the United States of America); its average weight is 1 ,100 milligrams for all dosages, with approximate volume from 18 mm x 9 mm and 5 mm height, and total approximate volume 810 cubic mm. This significant volume is to be accounted for the gastric retention due to excessive volume, that is, a mechanical retention form, obliterating the passage through the pylorus, that is, the communication between the gastric area and the duodenum, due to the pharmaceutical form geometric shape and large volume.

Document BR 0212931-0 by Arora et al. provides no solution for gastric retention.

Marketed tablets provided with gastric retention mechanisms are usually constructed with hydroxypropylmethylcellulose (HPMC), also known as hypromelose.

HPMC is a water-soluble excipient for linear polymers having no cross-links, promoting the release of drugs by dissolution or erosion.

Upon pharmacologically active ingredients releasing process, there is HPMC polymeric matrix soaking, causing volume increase up to 5 times the dry pharmaceutical form volume.

It is known that oral solid pharmaceutical forms ingestion difficulty increases as the average weight and the final average volume increase.

Although there are oral solid pharmaceutical formulations for metformin release, it is always desirable to improve the features of tablets ingestion, by reducing their average volume, when compared to the known forms constructed with

HPMC, and to increase their bioavailability, due to the longer time of gastrointestinal residence of these tablets. Gastric retention is an effective solution for maintaining inside the stomach oral solid pharmaceutical forms requiring active ingredient release on the upper portion of the intestine.

Polyacrylic acids are safe and effective in oral solid pharmaceutical forms and topic applications, and are approved by many pharmacopeias. Their use for gastro-retaining mechanisms has been studied for several authors, such as Leung et al. ("Polymer Structure Features Contributing to Mucoadhesion. II.," J. Contr. ReI., 12(3), 187-94, 1990), who showed that polyacrylic acid provides gastric retention in animals. Ch^'ng et al. showed that 51Cr-marked polyacrylic acid has been retained in stomach of rabbits for 17 hours, versus 8 hours in the control group ("Bioadhesive Polymers as platforms for Oral Controlled Release Drug Delivery. II. Synthesis and evaluation of Some Swelling, Water-Insoluble Bioadhesive Polymers", Journal of Pharmacological Science, 74, 229,1985.)

The words "bioadhesion" and "mucoadhesion" used herein mean the ability of a synthetic material to adhere to the mucous membrane, resulting in mechanical stabilization of said material for a prolonged period of time. This concept used upon release of pharmacologically active ingredients relates to the possibility of increased bioavailability by release from muco- or bioadhered pharmaceutical forms.

"Mucous membranes" means the ectodermal origin coating tissues, covered with epithelium which are involved in absorption and secretion processes. Mucous membranes cover cavities exposed to external environment and the internal organs. Mucus means the viscous fluid secreted by mucous membranes and glands, essentially a mucin biofilm. Absorption mucous membranes relate to mucous membranes in pharmaceutical interest, such as mouth, ophthalmic, nasal, gastric, intestinal, rectal and anal mucosas.

To be bioadhesive, the material must chemically and mechanically interact with the mucus, which is a highly hydrated gel composed of mucin, which are flexible glycoproteins chains with cross-links covering the mucous membranes, including the stomach. FIGURE 1 enclosed shows a schematic view of mucus, showing the glycoproteins chain, comprised of protein nucleus (1) and oligosaccharides chain (2). FIGURE 2 enclosed shows polyacrylic acid chain (A) interpenetration with mucus (B), according to Peppas & Buri, J. Controlled Release, 2,257,1985.

Polyacrylic acid polymers are molecules with high molecular weight, with cross-links based on polyalkyl ethers or divynil glycols, in the form of flocculated powders of primary particles with 0.2 μm diameter. Each primary particle may be visualized as a network of polymeric chains interconnected by cross-links. Linear polymers are soluble in polar solvents, such as water and alcohol.

Polyacrylic acid polymers used to be polymerized with the use of benzene as solvent, under commercial name Carbomer®. However, these polymers processing has been recently modified, and now solvents as ethylacetate and cyclohexane are being used, whose toxicological risk is significantly lower, with commercial name

Carbopol®, also produced by Noveon Inc.

It shall be observed that U.S. Pharmacopeia 2006 kept the denomination Carbomer for this new polyacrylic acid polymer, which is now benzene-free. Monograph titled Carbomer 940 (marketed as Carbopol® 940 NF polymer) establishes that the polyacrylic acid polymer is a polyacrylic acid polymer having cross-links with pentaerythritol allyl-ethers, containing between 56% and 68% of polycarboxilic acid groups. Aqueous dispersion viscosity at 0.5% for this acid is between 40,000 and 60,000 centipoise. The benzene-free aspect is an important advance in polyacrylic acid technology, considering the high carcinogenic potential of the solvent.

Polyacrylic acid polymers form gels when exposed to an environment with pH between 4 and 6, because the main chains groups ionize, leading to repulsion forces arising between the anions, forming the gel imbibed in the environment fluid. Polymers with cross-links are not water-soluble, but form colloidal gel dispersions.

Bioadhesive material, when in contact with mucous membranes, establishes a binding mechanism with mucine, through hydrogen bridges with the carboxylic groups found in polyacrylic acid polymers.

In low pH ranges, i.e., pH 5.0 or less, there is high adhesion by hydrogen binding with proteins or polysacharides usually found in mucine. It is quite known that the stomach pH is under this value, pH 5.0, usually between pH 1.0 and pH 5.0.

Mortazavi et al. ("As In Vitro Assessment of Mucus Adhesive Interactions",

IntU.Pharm., 124(2), pages 173-182,1995) also suggest that the binding via hydrogen bridges may occur by polyacrylic acid polymer chains interpenetration with mucine polysacharides chains.

Oral solid pharmaceutical forms constructed with polyacrylic acid innovatively provide a lower final volume than the oral solid pharmaceutical forms constructed with HPMC. This happens because the gastric retention mechanism provided by the tablets constructed with HPMC is essentially mechanical, and the gastric retention mechanism provided by pharmaceutical forms constructed with polyacrylic acid is based on bioadhesion biochemical mechanisms. The expansion of oral solid pharmaceutical forms constructed with polyacrylic acid, whose final volumes are lower than the tablets constructed with

HPMC, is made through thin webs, due to the cross-links mechanism the polyacrylic acid polymers have. Additionally, the cross-links provide final molecular weight, obtained by stechiometry, reaching billions.

Polyacrylic acid release mechanism is based on Fick's Law, i.e., the release occurs according to the release time square root, providing the polyacrylic acid matrix tablets with releasing capacity with zero order or close to zero order.

It has been observed that the HPMC matrices drug release mechanism, otherwise, does not provide this condition, as the release mechanisms provided release is higher in the first quarter of the time axis. FIGURE 3 shows the adhesion force compared among several types of polymers (source: Forςa de Adesao de Varios Polimeros, segundo Smart.J.D. - Drug Development and Industrial Pharmacy, 18(2), 223-232,1992). Thus, the polyacrylic acid drug release model offers a lower risk of burst effect than that offered by tablets based on HPMC matrices, namely the lower occurrence of release peaks.

Increased bioavailability is a result of polyacrylic acid bio- or mucoadhesive properties. The term "bioavailability" is used herein as a fraction of a given dose reaching the systemic circulation. By definition, when the administration is intravenous, the bioavailability is 100%. However, when the medication is given through other ways, the bioavailability is reduced, as a result of first passage mechanisms and several enzymatic changes. Several works discuss increased bioavailability for drug release, i.e., higher drug concentration in the bloodstream from release from tablets or capsules with the use of polyacrylic acid polymeric matrices, due to the higher gastrointestinal time of residence offered by these formulations.

Lehr et al. have already mentioned this generic property for bioavailability increasing in 1990, in their work "Oral Bioadhesive Drug Delivery Systems -Effects on G.I. Transit and Peptide Absorption", in Pharm.Res, 7(9), September (supplement), PDD 7226,1990.

Longer et al. have shown that the chlorothiazide bioavailability was 1.95 times higher in rats than in the control, in their work "Bioadhesive Polymers as Platforms for Oral Controlled Drug Delivery. III. Oral Delivery of Chlorothiazide Using a Bioadhesive Polymer" in J.Pharm.Sciences, 74 (4),406-411 ,1985. Hosny and Al-Angary described increased absorption and improved bioavailability of slow release indomethacin suppositories in their work "Bioavailability of Sustained Released Indomethacin Suppositories Containing Polycarbophil", in Intl.J.Pharma., 113(Jan 16), page 209-213,1995. Other works have reported decreased drug concentration peaks, with smoother release curve. Capan et al. taught that slow release acetylsalicylic acid tablets constructed with 15% polyacrylic acid as release controlling agent for the pharmacologically active agent showed more uniform rates than immediate release tablets, in their work "Formulation and In Vitro - In Vivo Evaluations of Sustained Release Acetylsalicylic Acid Tablets", Pharmaceutical Industry, 51 (4),443-8,1989.

It is known in the art that the sulfonylureas show therapeutic effectiveness against hyperglycemic pictures, while being water insoluble and practically insoluble at low pH.

Sulfonylureas hypoglycemic power is directly related to the plasma level, i.e., about 25% of type 2 diabetes patients treated with sulfonylureas reach plasma glucose levels under 140 mg/dl; however, the remaining portion does not reach this level and shall receive combined therapy, such as therapy with biguanides, for example, metformin. Auto-antibodies may also occur for insulin-producing cell islets, and the presence of these antibodies requires increased insulin treatment, due to cell islets loss. Cell autoimmunity signals occur in 12% of patients with type 2 diabetes from 65 years old on.

Additionally, these type 2 diabetes patients have increased C-reactive protein and increased fibrinogen. A marked activation of acute response phase may partly explain the insulin secretion deficiencies. The use of combined biguanides and sulphonylureas may significantly reduce the autoimmunity and apoptosis effects on decreased insulin secretion.

These effects occur both for the first sulphonylureas generation and for the second generation. The first generation comprises drugs chlorpropamide and glibenclamide, and the second generation comprises drugs glipzide, gliburide and glimepiride.

Combined use of biguanides and sulphonylureas has a practical difficulty, that is, dissolution ranges in different pHs, that is, metformin is frankly water-soluble, and sulphonylureas are soluble only in higher pH ranges than the ones found in the gastric environment. Most coating films are solubilized in non-aqueous solvents for direct application on tablets, making non-water-soluble drugs dissolution easier, such as Glimepiride (DrugBank number APRD00381). Diluting this drug in common solvents for coating films, such as ethyl alcohol, isopropyl alcohol and acetone, allows its integration to immediate release films in acid pH, for example, from 2 to 5, and absorption in intestinal areas with higher pH, for example, from 5 to 7, such as colon area. The main scope of the present invention are pharmaceutical forms using water-soluble coating films, or layers, or coatings, as additional carriers to the bioadherent tablet. pH-modulated coating films, i.e., the ones having immediate dissolution in gastric environment, are known in the art and commercially available. The combined biguanides and sulphonylureas release model known in the art provides no solution for the different solubility conditions in both drugs classes.

Ochoa document BR 0502691 de Ochoa provides the possibility of combining metformin and other insoluble drugs, but shows no technical solution allowing distinguished release for salts with diametrically opposite solubility behaviors. Danping document BR 0215018 offers as a solution the combined compression of two drugs.

Although there are metformin extended release formulations, process and final product improvement is always desirable, as well as association with other drugs. Composition and pharmaceutical form have been developed, comprising a bioadherent nucleus with gastric retention capacity, containing extended release, water-soluble anti-glucose-providing agent, also soluble in pH lower or equal to 5, and one of the acid-modulated coating layers possibly containing coadjuvant pharmacologically active agents, also having anti-glucose-providing effect, non- water-soluble and soluble in pH higher or equal to 5, immediate release, also comprising benzene-free polymerized polyacrylic acid or its derivatives as controlled release regulating agent, additionally to pharmaceutically acceptable excipients.

The present invention is based on an innovative gastric retention mechanism, for biguanides pharmaceutical form or pharmaceutical composition, preferably metformin, with reduced final tablet volume, keeping dissolution profile and serum levels values with therapeutic effectiveness. The composition comprises about 500 mg to 1.25 g metformin, or its pharmaceutically acceptable salts, such as hydrochloride, succinate, fumarate and others. The oral solid pharmaceutical form composed of anti-hyperglycemic agent and excipients is appropriate to promote gastroretention by bioadhering the reduced volume pharmaceutical form to the gastric mucosa, with consequent bioavailability increase. The pharmaceutical form is intended to oral application as tablets or granulates. Thereto, it is herein presented the innovative solution of reduced volume bioadherent tablets for anti-hyperglycemic agents release, such as metformin, whose gastrointestinal time of residence is longer than oral solid pharmaceutical forms constructed with other non-bioadherent polymers, as well as the association with other anti-glucose-providing drugs by means of the coating film.

The bioadherent pharmaceutical composition or form innovatively allows the releasing of acid-modulated coating films and consequent release of sulphonylureas for the gastrointestinal tract environment, while the bioadherent biguanides releasing nucleus, such as metformin, is kept in the gastric environment by adhesive retention, allowing the release of highly soluble metformin, for example, for duodenal absorption.

The present invention also relates to a process for obtaining, or industrial production of, pharmaceutical forms, such as modified release tablets for anti- glucose-providing agents, preferably biguanides as metformin, with better clinical performance and reduced size when compared to pharmaceutical forms constructed with polymers with no adhesive capacity.

Additionally, the present invention claims the addition of coadjuvant drugs such as sulphonylureas, to the coating film, promoting a double carrier mechanism, to comprise the diametrically different solubility conditions between the biguanides, for example, metformin, soluble in low pH and aqueous solution, and sulphonylureas, insoluble in water and in low pH. As sulphonylureas the following may be used: glimepiride, glibuhde, glipzide, or also, their mixtures. Glimepiride is preferably used. The carrier film suffers immediate dissolution action, with the sulphonylureas being transferred to areas more favorable to absorption in the gastrointestinal area, such as the colon, for example, while the bioadherent nucleus releases biguanide, for example, metformin, in the proximal portion of the intestine, i.e., the duodenum, from the biguanide solubilization by bioadherent slow release mechanism, promoted by polyacrylic acid compositions, for example, Carbopol®, in direct compression pharmaceutical forms or by means of wet granulation. As coadjuvant agents, sulphonylureas may be used, such as: glimepiride, gliburide, glipzide, or their mixtures. Glimepiride or its pharmaceutically acceptable salt are particularly used, within the range from about 1 mg to about 5 mg in the polymeric coating film, by dosage unit. Gliburide or its pharmaceutically acceptable salt may be used, within the range from about 1 mg to about 6 mg in the polymeric coating film, by dosage unit. Glipzide or pharmaceutically acceptable glipzide salt may also be used, within the range from 2 mg to 12 mg in the polymeric coating film, by dosage unit. The controlled release pharmaceutical form according to the invention has an in vitro dissolution profile with no release peak (burst) when tested in type 2 apparatus at 75 rpm in 900 ml phosphate buffer pH 7.5 at 37⁰C, with dissolution from 5 to 30% metformin in 2 hours, 8% to 40% metformin release after 4 hours, 25% to 90% metformin release after 8 hours, not less than 50% metformin release after 12 hours, not less than 70% metformin release after 20 hours. It has no occurrence of a release peak (burst), with 50% of the maximum plasma curve height from 4 to 15 hours after administration. It has no occurrence of release peak (burst) either, with maximum plasma concentration not less than 5 times higher than the metformin plasma average in 24 hours. It has no occurrence of release peak (burst) and has maximum plasma concentration between 300 ng/ml and 1000 ng/ml after administration of a 500-mg metformin tablet, and also has maximum plasma concentration between 350 ng/ml and 1250 ng/ml after administration of 750-mg metformin tablet. Without departing from the scope of the invention, the expression "extended release coated tablet" means a solid pharmaceutical form to be administered p.o., which may be produced by physical compression of the active ingredient, i.e., metformin, and the excipients, i.e., the set of substances providing form, compressibility, mechanical strength and modulating the active ingredient release. The nucleus, i.e., the set comprising the excipients and the metformin, is coated with a film providing the nucleus with isolation from contact with the atmospheric air, which film is dissolved when in contact with the gastrointestinal medium.

The nucleus plus coating set releases the active ingredient in a modified way, i.e., from 1 to 24 hours after the tablet ingestion. "Modified release" is understood as the release process changing the active ingredient inherent solubility, i.e. metformin's.

The nucleus plus coating set allows active ingredient stability for a minimum two-year period. Stability may be defined as absence of degradation within legally acceptable limits, i.e., with active ingredient content from 90 to 110% within a minimum one-year period.

The nuclei may be produced with the dry or wet process. For the dry process, i.e., by direct compression, conventional powder mixture compaction methods are used, by means of a mechanical punch with axial force.

The excipients used for compression are preferably binder, such as starch from several origins, for example, from corn, microcrystalline cellulose, as product Avicel®, silicon dioxide, as for example Aerosil®, mannitol, lactose and polyethyleneglycol with molecular weight from 400 to 6000, polyvynilpirrolidone, such as Polyplasdone®, carboxymethylcellulose, carboxymethyl starch, dicalcium phosphate, talc and lubricants as stearate. The main regulating excipient for modified release is polyacrylic acid, such as Carbopol®. Several stains may be added, especially for distinguishing between the several dosages. According to a process to obtain the pharmaceutical form of the present invention, the adhesive nucleus for modified release is first obtained, containing anti- hyperglycemic agent, which goes on the solution coating containing release regulating agents or polymers, among which polyacrylic acid dissolved in organic solvent and, optionally, water. Compression may be performed in rotating compressing machines, such as

FETTE® and the nuclei shape may vary, as well as their size, such as convex, cylindrical, oblong biplane shapes.

The granules may be produced, for example, with the help of silicon dioxide, microcrystalline cellulose, such as Avicel®, and others as carbohydrates and starches. As binders the following may be used: gelatin, alginate, polyethyleneglycols, polymerized ethylene oxide, polyvynilpirrolidones, povidones and especially polyacrylic acid, such as Carbopol®. Detergent products may also be used, such as sodium lauryl sulfate.

Granules may be produced in a known manner, through wet process methods. The mass formed, for example, of active ingredient and microcrystalline cellulose and colloidal silicon dioxide, is mixed in a rotating mill. Thereafter, the mass is transferred to GLATT® granulator, for example, adding solvents such as ethyl alcohol and polyacrylic acid, such as Carbopol®, until complete dispersion. The granules are dried, by placing the mass composed of metformin and excipients described above on a fluidized bed, and allowing compression, which may be made in compressing machines, such as FETTE®. The usual compression techniques are described in Remington: "The Science and Practice of Pharmacy", 19^th ed. Vol. 11 (1995) (Mack Publishing Co., Pennsylvania), and "Remington's Pharmaceutical Sciences", Chapter 89, pages 1633-1658 (Mach Publishing Company, 1990), The purpose of the coating is to preserve the active ingredient stability, with the protection provided by isolating the nucleus from the external medium, by applying the coating. Preferably the coating is hydrophilic, permeable to water and to the wet environment in the gastrointestinal tract. The coating has an additional function of masking the strongly bitter flavor inherent to metformin. The materials forming the coatings may be chosen from the group composed of: polyacrylic acid or its derivatives, polyvynilpirrolidone, polyvynilpirrolidone copolymers, polyvynil acetate, hydroxypropylmethylcellulose (HPMC) or its derivatives, ethylcellulose, or their mixtures. These polymers are dispersed in ethyl alcohol, isopropyl alcohol or acetone, to compose the application vehicle.

To the solution of polymers in alcohol, pigments, talc or moisturizing agents may be added. The coating forming material may be sprayed as an aqueous or alcoholic dispersion, with the use of rotating coating equipment, such as GLATT® or ACCELA COTA®. Plasticizing agents, such as triethyl acetate, other phtalates, or polyethylene glycols may be added to the dispersion.

The pigments that may be included in the dispersion may be white as titanium dioxide, and may be combined with ferric oxide.

The coatings may contain pharmacologically active substances, as sulphonylureas, such as glimepiride, gliburide and glipzide, or their mixtures.

Sulphonylureas active agents, for example, glimepiride, are slowly dissolved in the coating polymer alcoholic solution, while the solution is sprayed on the metformin modified release adhesive nuclei.

According to the release mechanism, the immediate dissolution coating films release sulphonylureas to the medium, and those are transported to the intestinal environment while still insolubilized. In the intestinal tract environment the pH increases, due to the presence of biliary products, making absorption easier. At the same time, the gastric retention remains in the bioadhesive tablet nucleus, which releases biguanide, for example, metformin, into the gastric environment, for duodenal absorption. In a same product, therefore, there is site-dependent distinguished release, comprising the pharmacokinetic requirements of each drug class. Below there are some examples that may be used to better explain the scope of the invention, which shall not be used with limiting purposes thereto.

EXAMPLE 1

Tablets were prepared containing the formulation indicated below:

Component mass compared to the total mass

Metformin hydrochloride - 750.0 mg Microcrystalline cellulose - 98.0 mg

Carbopol 71G - 116.6 mg

Carbopol 971 P - 74.2 mg Colloidal silicon dioxide 5.3 mg

Magnesium stearate 15.9

Opadry blue ® 31.8

Opadry FX ® 10.6

Metformin hydrochloride was mixed with Carbopol® 971 P in a high-speed mixer. Water was added as granulation liquid to the mixture, and granulation was performed until reaching the appropriate consistency. The granules were calibrated with an appropriate device and dried on a fluidized bed. Microcrystalline cellulose, colloidal silicon dioxide and Carbopol® 71 G were added and homogenization was performed. At last, magnesium stearate was added and homogenization was repeated. The final mixture was compressed to form Metformin Hydrochloride XR 750 mg tablets.

The tablets were coated with an alcoholic preparation consisting of Opadry blue® dispersed in coating equipment. Thereafter, they were coated with an overcap or overlayer, with the use of aqueous Opadry FX preparation.

EXAMPLE 2

Tablets were prepared containing the formulation indicated below:

Component mass con

Metformin hydrochloride - 750.0 mg

Glimepiride - 2.0 mg

Microcrystalline cellulose - 98.0 mg

Carbopol 71 G 116.6 mg

Carbopol 971 P 74.2 mg

Colloidal silicon dioxide - 5.3 mg

Magnesium stearate - 15.9

Opadry blue ® - 31.8

Opadry FX ® - 10.6

Metformin hydrochloride was mixed with Carbopol® 971 P in a high-speed mixer. Water was added as granulation liquid to the mixture, and granulation was performed until reaching the appropriate consistency. The granules were calibrated with an appropriate device and dried on a fluidized bed. Microcrystalline cellulose, colloidal silicon dioxide and Carbopol® 71 G were added and homogenization was performed. At last, magnesium stearate was added and homogenization was repeated. The final mixture was compressed to form Metformin Hydrochloride XR 750 mg tablets. The tablets obtained were coated with an alcoholic preparation consisting of

Opadry blue® dispersed, along with glimepiride, in coating equipment. Thereafter, they were coated again with an overcap or overlayer, with the use of aqueous Opadry FX preparation.

Claims

I) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION comprising a bioadherent nucleus obtained by compression, with gastric retention capacity, containing extended release, water-soluble anti-glucose-providing agent, also soluble in pH lower or equal to 5, comprising, as controlled release regulating agent, benzene-free polymerized polyacrylic acid or its derivatives, additionally to pharmaceutically acceptable excipients. 2) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 1 , wherein the anti-hyperglycemic agent is a biguanide. 3) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 2, wherein the metformin, or the pharmaceutically acceptable salts thereof, is used. 4) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 3, wherein it is possible to use metformin salts, such as: hydrochloride, succinate, fumarate, among others. 5) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claims 1 to 4, wherein it comprises from about 500 mg to 1.25 g metformin. 6) PHARMACEUTICAL COMPOSITION containing one or more acid-modulated coating layers, with pharmacologically active agents, with anti-glucose-providing effect, non-water-soluble and soluble in pH higher or equal to 5, with immediate release.

7) PHARMACEUTICAL COMPOSITION according to claim 6, wherein the active agents are sulphonylureas.

8) PHARMACEUTICAL COMPOSITION according to claim 7, wherein it is possible to use: glimepiride, glibuhde, glipzide, or their mixtures.

9) PHARMACEUTICAL COMPOSITION according to claim 6, wherein it is possible to use glimepiride or its pharmaceutically acceptable salt within the range from about 1 mg to about 5 mg in the polymeric coating film, by dosage unit.

10) PHARMACEUTICAL COMPOSITION according to claim 6, wherein it comprises gliburide or its pharmaceutically acceptable salt within the range from about 1 mg to about 6 mg in the polymeric coating film, by dosage unit.

I I) PHARMACEUTICAL COMPOSITION according to claim 6, wherein it comprises glipzide or its pharmaceutically acceptable salt within the range from about 2 mg to about 12 mg in the polymeric coating film, by dosage unit. 12) PHARMACEUTICAL COMPOSITION according to claims 1 and 6, wherein it may also comprise agglutinating, lubricating, coloring, detergent, plasticizing, moisturizing agents, among others.

13) PHARMACEUTICAL COMPOSITION according to claim 12, wherein it may comprise microcrystalline cellulose, silicon dioxide, magnesium stearate, sodium lauryl sulfate.

14) PHARMACEUTICAL COMPOSITION according to claim 12, wherein it may comprise carbohydrates, starches, gelatin, alginate, polyethylene glycols, polymerized ethylene oxide, polyvynilpirrolidones, povidones. 15) PHARMACEUTICAL COMPOSITION according to claim 12, wherein it is possible to use as excipients: corn, microcrystalline cellulose, silicon dioxide, mannitol, lactose, polyethylene glycol with molecular weight from 400 to 6000, polyvynilpirrolidone, carboxymethylcellulose, carboxymethyl starch, dicalcium phosphate. 16) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claims 1 to 15, wherein it comprises a biguanides nucleus, in which the main release regulating agent is polyacrylic acid coated with polymeric films as sulphonylureas carrier.

17) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to the previous claims, wherein it has a dissolution profile for metformin in vitro with no release peak (burst), when tested in a type 2 apparatus at 75 rpm in 900 ml phosphate buffer pH 7.5 at 37⁰C, with dissolution from 5 to 30% metformin in 2 hours, 8% to 40% metformin release after 4 hours, 25% to 90% metformin release after 8 hours, not less than 50% metformin release after 12 hours, not less than 70% metformin release after 20 hours.

18) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 17, wherein it has no metformin release peak occurrence (burst), with 50% of the maximum plasma curve height from 4 to 15 hours after administration.

19) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 17, wherein it has no metformin release peak occurrence (burst), having maximum plasma concentration not less than 5 times higher than the metformin plasma average in 24 hours.

20) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 17, wherein it has no metformin release peak occurrence (burst), having maximum plasma concentration between 300 ng/ml and 1000 ng/ml after administration of 500 mg metformin tablet. 21) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 17, wherein it has no metformin release peak occurrence (burst), having maximum plasma concentration between 350 ng/ml and 1250 ng/ml after administration of 750 mg metformin tablet. 22) CONTROLLED RELEASE PHARMACEUTICAL COMPOSITION according to claim 17, wherein it is supplied as tabletsOr granulates.

23) PROCESS TO OBTAIN PHARMACEUTICAL FORM according to the previous claims, wherein at first the adhesive nucleus for modified release is obtained, containing the anti-hyperglycemic agent, mainly composed of release regulating agents or polymers, among which polyacrylic acid dissolved in organic solvent and optionally, water.

24) PROCESS TO OBTAIN PHARMACEUTICAL FORM according to the previous claims, wherein it is also possible to use as release regulating agents: polyvynilpirrolidone, polyvynilpirrolidone copolymers, polyvynil acetate, hydroxypropylmethylcellulose (HPMC) or its derivatives, ethylcellulose, or their mixtures.

25) PROCESS TO OBTAIN PHARMACEUTICAL FORM according to the previous claims, wherein it is possible to use as organic solvent: ethyl alcohol, isopropyl alcohol, acetone, or also, their mixtures. 26) PROCESS TO OBTAIN PHARMACEUTICAL FORM according to the previous claims, wherein there is a combination of an anti-glucose-providing pharmacologically active agent in the nucleus and another anti-glucose- providing agent contained in the coating.