MXPA00006213A - Tablet for instant and prolonged release of one or more active substances - Google Patents

Abstract

The invention relates to a multilayer tablet for the instant and then prolonged release of active substances comprising at least two superposed layers, characterized in that:a first outer layer is composed of a mixture of excipients and of a first active substance, the said first layer allowing immediate release of the said first active substance;a second layer, arranged in contact with the said first layer, consists of a nonbiodegradable, inert porous polymeric matrix in which a second active substance is dispersed.

Description

COMPRESSED FOR THE INSTANT AND PROLONGED RELEASE OF ONE OR MORE ACTIVE SUBSTANCES DESCRIPTION OF THE INVENTION The invention relates to solid galenic forms of the type of a controlled release tablet for the instantaneous and prolonged release of one or more active substances. The importance of such galenic forms is indisputable. The release of an active substance allows its bioavailability virtually instantaneous, which is particularly convenient in the case of patients suffering from acute conditions. However, in the case of active substances with a short half-life, the therapeutic activity is only temporary. But for the therapy to be effective, a continuous and regular contribution of the active ingredient is usually necessary. For these purposes numerous systems of immediate and prolonged release have been developed. On this subject reference is made, for example in the following patents and prior art patent applications: WO 96/03111, US 4,990,335, REF.ligyg-L EP 352 190, BE 905 282, EP 106 443, EP 36 350, EP 615 444 and EP 220 670. However, in prior art systems the release kinetics of the active ingredient depends on various factors such as enzymatic activity and pH conditions that vary substantially from one individual to another and in the same individual, depending on whether they are on an empty stomach or not. In addition, pH conditions vary throughout the entire gastrointestinal tract. For this reason it is difficult to accurately predict, in vivo, the release profile of a given substance after administration of the instant and prolonged release systems of the prior art. The present invention aims to solve this problem by providing tablets that retain their release characteristics of the active substances, regardless of the conditions of administration in vivo. The tablets of the invention ensure excellent reproducibility of the results and allow a more precise control of the release rates during the prolonged release phase of the active ingredient. By using the tablets of the invention, the supply of active ingredients to the body can be optimized, taking into account both the tolerance of the subject to the active ingredient and the pharmacokinetic and metabolic profiles of the active ingredient. The tablets of the invention are advantageous from the point of view of the formulation of the active ingredients, since a careful choice of the excipients makes it possible to obtain tablets with high concentrations of the active ingredients. In this way tablets can be obtained with very high doses and an acceptable size for oral administration. In particular, the invention relates to multilayer tablets for the instantaneous and also prolonged release of active substances, which contain at least two superimposed layers and which are characterized in that: a first outer layer is composed of a mixture of excipients and a first active substance, the first layer allowing the immediate release of the first active substance; a second layer is in contact with the aforementioned first layer and is composed of a porous, inert, non-biodegradable, psimérica matrix in which a second active substance is dispersed. The second layer is in contact with the first layer and is completely or only partially coated by the first layer. In the first case both layers are concentric. In the second case, only one of the surfaces of the second layer is in contact with the first layer: from now on, this type of tablets is designated as "of parallel layers" and the shape of the tablet is not important and is , in particular, ovoid. It should be noted that in this case both layers have an external surface, while with the other surface ~ they contact each other. - The tablets of the invention preferably have two layers. However, the invention also encompasses multilayer tablets, as long as they contain the combination of the first and the second layer "defined above With some active ingredients may appear stability problems of the active ingredient that is included in the matrix of prolonged release.

In these cases it is advisable to opt for the preparation of tablets with concentric layers. The kinetics of release of the active ingredient depends, in each case, on the exact composition of the layer in question. Release kinetics are modulated by adapting the nature and quantity of the excipients that make up both layers. A characteristic of the first layer is that it rapidly disintegrates at the site of administration. On the contrary, the second layer is not biodegradable. Its matrix is inert in that it does not react with the environment that surrounds it. The matrix of the second layer maintains its physical and chemical integrity throughout the prolonged release of the active ingredient, independently of pH variations. Since the first layer disintegrates instantaneously upon contact with an aqueous medium such as the physiological medium, it is very easy to understand the reason why the release of the first active substance is immediate. As in the case of the second layer the constitutive matrix is inert (it does not wear out or swell in an aqueous medium), the release of the second active substance occurs by leaching and diffusion. The surrounding aqueous medium gradually penetrates into the inert pores of the matrix and progressively dissolves the active substance that is dispersed in the inert matrix. The mechanism of diffusion is essentially slow, which makes it possible to understand the reason why the release of the active ingredient is prolonged in this case. While the mechanism of disintegration of the first layer does not depend, or very little depends, on the nature of the active substance, it is noteworthy that the less or more hydrophilic nature of the active substance of the second layer can influence the kinetics of leaching / diffusion. However, the invention is not limited by the nature of the active substances. Each layer can contain a different active ingredient. However, a specific embodiment of the invention is one in which the first and second layers have the same active substance. . The active substances can be chosen, in particular, from any of the following groups (The usual international names have been adopted to designate the active substances): - the drugs that act against asthma such as 2-ethoxymethyl-4 (3H) -pteridinone and bronchodilators such as theophylline, and / or some anti-inflammatory or antihistamines of the ketotifen type; - medicines that are active in the treatment of diabetes and its associated complications of neurological, nephrological, ocular or vascular type. By way of example, mention may be made of metformin, hypolipidemic agents such as fenofibrate or pravastatin and antiathero- matous agents in general; - drugs that act in the treatment of alcoholism such as acamprosate; - peripheral analgesics, for example, para-aminophenol derivatives such as paracetamol, salicylated derivatives such as aspirin, diflunisal, propionic acid derivatives such as ibuprofen, fenoprofen, ketoprofen, derivatives of aminoquinoline such as floctafenin, pyrazolone derivatives such as noramidopyrine; - central analgesics such as dextropoxyphene, codeine, morphine, pethidine, dextromoramide, buprenofine, nalbuphine, pentazocine; - antispasmodics such as thimerium, difermerin, phloroglucinol, trimebutin, pinaverium, prifinium; - non-steroidal anti-inflammatories and, for example: . the arylpropionic derivatives such as ketoprofen, ibuprofen, naproxen, flurbiprofen, alminoprofen, thiaprofenic acid,. the arylacetic derivatives such as dichlorophenac, fentiazac,. arylcarboxylic derivatives such as fenbutene and etodolac,. anthranilic derivatives or fenamates such as niflumic acid and mefenic acid,. the indole derivatives such as indomethacin and oxametacin,. oxicam compounds such as piroxicam, tenoxicam,. pyrazole derivatives such as phenylbutazone, . indene derivatives such as sulindac; - steroid anti-inflammatories such as corticosteroids of the prednisone, prednisolone and methylprednisolone type; antibiotics of the beta-lactam type such as penicillins, of the cephalosporin type such as cefuroxime axetil, of the beta-lactamase inhibitor type such as clavulanic acid, of the aminoglycoside type such as neomycin, of the type of the macrolides such as spiramycin and erythromycin, of the tetracycline type such as minocycline and doxycycline, of the sulfamide type such as sulfadiazine, of the quinolone type such as perfloxacin; - antituberculous agents such as isoniazid, rifampicin, ethambutol, pyrazinamide; - polyene antifungals such as amphotericin B, nystatin; - antifungals based on imidazole such as miconazole, ketoconazole, fluconazole, flucytosine, griseofulvin; - antivirals of the type of zidovudine, acyclovir, adamantane such as rimantadine, amantadine and moroxidine; beta-blockers such as acebutolol, celiprolol, atenolol, betaxolol, etoprolol, bisoprolol, propanolol, nadolol, timolol, tetratolol, sotalol, pindolol, penbutolol, carteolol, oxiprenolol, labetalol; - nitrated derivatives such as isosorbide dinitrate, isosorbide monitrate, pentaerythrityl tetranitrate, erythrityl tetranitrate; - the antianginics of the sidinone type such as molsidomine and linsidomine; cardiotonics such as orciprenaline, or those of the digitalin type such as digoxin, digitoxin, - diuretics such as furosemide, bumetanide, clopamide, thiazide-type drugs such as hydrochlorothiazide, xipamide, of thienyl acid, indapamide, cyclintanin, spironolactone, canrenone, amiloride, triamterene; - the inhibitors of the conversion enzymes such as captopril, enalapril, lisinopril, perindopril, quinalapril, ramipril, benazepril; - calcium inhibitors such as nifedipine, nicardipine, nitrendipine, diltiazem, verapamil, bepridil; - antihypertensives such as rilmenidin, clonidine, metildipa, dihydralazine, prasozine, uradipil, minoxidil; - antiarrhythmics such as quinidine, disopyramide, cyzepoline, propafenone, flecainide, aprindine, nadoxolol, mexiletine, bretylium, amiodarone; - anti-ischemic drugs such as naftidrofuryl, trimetazidine, pentoxifylline, nicerogoline, blufomedil, dihydroergotoxin, dihydroergocris, dihydroergocryptine, moxysilite, raubasin, vincane, papaverine, nicotinic acid; - the ventonic ones such as vitamin P; - correction of hypotension such as heptaminol; - hormones such as thyroid hormones of the levothyroxine sodium type; - drugs that stimulate gastro-duodenal motor skills such as cisapride, dompreridone; antiemetics such as metoclopra ida, metopimaz ina, aliprazide, odansetron, scopolamine; antiulcerogenic agents such as ranitidine, famotidine, nizatidine, cimetidine, omeprazole, those of the tglandin type such as misoprostol, sucralfate, aluminum hydroxide; antidiarrheals such as loperamide, diphenoxylate, drugs that reconstitute the bacterial flora and those that reconstitute the yeast flora; - intestinal antiseptics such as nitrofuran; - contraceptives such as oestroproges togenss; - antianemic agents such as iron; - antihistamines such as phenothiazine; - vitamins such as thiamine, nicotinamide, pyridoxine, biotin, ascorbic acid, cyanocobalamin, retinol, colecalciferol; antiepileptics such as valproic acid, phenytoin, carbamazepine, etosuxiniraide, vigabatrin; - anti-migraine agents such as oxetorone, indoramin, rye ergot derivatives such as dihydroergotamine, methysergide, tricyclic derivatives such as pizotifen; - the anticoagulants such as the K antivitamins; - anti-Parkinson's compounds such as levodopa, selegiline, lisuride, bromocript ina, biperiden, orphenadrine, procyclidine, tropatepine, copolamine s; - the anxiolytics that are derived from benzodiazepines such as clotiazepa, tofisopam, oxazepam, alprozolam, lorazepam, bromazepam, prazepam, buspirone, alpidemo, hydroxyzine, -eprobamate, febarbamate; - antidepressants such as quinupramine, desipramine, imiphora, clomipramine, amitriptyline, viloxazine, amineptine, fluvoxa ina, fluoxetine, thianeptin, oxafloxane, maprotiline, mianserin, trazodone, the medifoxamina, the toloxatona, the MAOIs; - hypnotics such as zopiclone, zolpidem, and benzodiazepine derivatives such as flunitrazepam, nitrazepam, triazole, phenothiazine derivatives such as niaprazine, doxylamine, barbiturates such as butobarbital, amobarbital , phenobarbital; - normothymics such as lithium, valpromide; "neuroleptics such as thioxanthene, pimozide, loxapine, carpipamine," phenothiazine derivatives such as chlorpromazine, thioridazine, fluphenazine, butyrophenone derivatives such as haloperidol, penfluridol, pipamperon, benperidol, benzamide derivatives such as sulpiride, amisulpiride, thiapride, sultopride; - antimetabolites such as methotrexate, mercaptopurine, fluorouracil, cytarabine, hydroxo-urea, asparaginase; alkylating agents such as busulfan, pipobro anus, procarbazine, nitrogenous mustard derivatives such as chlora bucylo, cyclophos famida, stramus tina, melphalan, lomustine, fotemustine; - anticancer steroids such as methoxyproges terone, gestonorone, norethisterone, diethylstilbestrol, dienestrol; - and in general, other peptides with therapeutic activity. A pharmaceutically acceptable salt of any of the active ingredients mentioned above that are capable of being converted into salts can also be chosen as the active ingredient. The content of the ingredient -active in the first layer depends on the pathology to be treated. This content must be high, and the active substance can represent up to 99.0% of the total weight of the first layer, for example, it can represent from 1 to 99.0% by weight, preferably from 85 to 95% of the total weight of the first layer. cap. The second layer can contain up to 98.5% by weight of the active ingredient, for example, it can contain from 1 to 95% by weight, preferably from 60 to 80%. In the prior art numerous instant release compositions are known, which allows the person skilled in the art to be free to inspire to prepare the first layer. In particular, the person skilled in the art will select the components of the first layer in such a way as to ensure a rapid disintegration thereof upon contact with water or with physiological liquids. The incorporation of a disintegrating agent within this type of layer is particularly known. The role of the agent is to produce the disintegration of the tablet in the presence of water or physiological liquids. These disintegrating agents are normally included in the layer in an amount comprised between 0 and 15% by weight, preferably between 2 and 5% by weight. Examples of such disintegrating agents are: alginic acid, calcium carboxymethylcellulose, sodium carboxymethylcellulose, anhydrous colloidal silica, croscarmellose sodium, crospovidone, guar gum, magnesium and aluminum silicate, methylcellulose , microcrystalline cellulose, polacrilin potassium, cellulose, pregelatinized starch, sodium alginate, sodium starch glycolate, starch and effervescent mixtures that are known in the prior art "for their disintegrating action. They are part of the substances capable of rapidly causing the disintegration of the first layer, especially when the latter comes into contact with gastric acids.These mixtures usually contain alkali metal or alkaline earth metal carbonates or bicarbonates or sodium glycine carbonate. additives that can be incorporated in the immediate release layer are the thinners, binders, lubricants, antioxidants, dyes, sweeteners, flavors and acidulants, wetting agents, hydrophilizing agents such as sorbitol and cyclodextrins, osmotic agents such as mannitol, pH corrective agents , stabilizers such as trehalose and mannitol, adsorbing agents, chelating and sequestering agents and gastro-resistant film excipients of the cellulose acetylphthalate type and polymethacrylates. By way of example, any of the diluents listed below may be chosen, or a combination thereof: calcium carbonate, calcium sulfate, sucrose, dextratds, dextrin, dextrose, dicalcium phosphate dihydrate, kaolin, magnesium carbonate , magnesium oxide, maltodextrin, cellulose, microcrystalline cellulose, sorbitol, starches, pregelatinized starch, talc, tricalcium phosphate and lactose. Among the binders there may be mentioned: gum arabic, gum tragacanth, guar gum, alginic acid, sodium alginate, sodium carboxymethyl cellulose, dextrin, gelatin, hydroxyethylcellulose, hydroxypropylcellulose, liquid glucose , the magnesium and aluminum silicate, the maltodextrin, the povidone, the pregelatinized starch, the starch and the zein. Lubricants are glidants (such as anhydrous colloidal silica, magnesium trisilicate, magnesium silicate, cellulose, starch, talc or tricalcium phosphate) or antifriction adhesives (such as calcium stearate, monostearate glyceryl, glyceryl, palmitoes, hydrogenated vegetable oils, paraffin, magnesium stearate, polyethylene glycol, sodium benzoate, sodium lauryl sulfate, fumaric acid, stearic acid or zinc stearate and talc ).

The person skilled in the art can choose as an antioxidant any of the following compounds indicated by way of example: ascorbic acid, ascorbyl palmitate, fumaric acid, propyl gallate, sodium ascorbate and sodium metabisulfite, alpha-tocopherol, malic acid , BHA and BTH. Preferred wetting agents are: sodium docosate and sodium lauryl sulfate, which are anionic surfactants; - benzalkonium chloride, benzethonium chloride and cetrimide which are cationic surfactants; - glyceryl monooleate, fatty esters of polyoxyethylene sorbitan, (poly) vinyl alcohol and sorbitans which are nonionic surfactants. Among the pH regulating agents are the acidifying agents of the citric acid type, hydrochloric acid, lactic acid, tartaric acid, and also the alkalizing agents of the monoethanolamine, diethanolamine and triethanolamine type, potassium citrate, sodium bicarbonate. , sodium citrate dihydrate. Examples of the adsorbents are bentonite, colloidal anhydrous silica, kaolin, magnesium and aluminum silicate, microcrystalline cellulose and cellulose. The acid monohydrate can be used as chelating and sequestering agents. citric acid, edetic acid, disodium phosphate, monosodium phosphate, potassium citrate, tartaric acid and sodium citrate dihydrate The amounts of these additives are those that are usually used in the prior art. Binder may represent from 0.5 to 25% by weight, preferably from 2 to 5% by weight of the first layer Lubricants are incorporated into the first layer in an amount comprised between 0.01 and 10% by weight. As a guide it can be mentioned that the amount of excipients of tro-resistant gas film varies between 0.5 and 9% by weight.It should be noted that all the additives mentioned above, with Except for the disintegrating agents, they can also be added to the extended release layer in similar proportions. The extended release layer may also contain diluents such as glyceryl palmito stearate, hydrogenated vegetable oils, polyethacrylates, potassium chloride and sodium chloride. Binders such as these may also be incorporated in the extended release layer. such as carbon, ethylcellulose, hydrogenated vegetable oils, hydroxypropylmethylcellulose, methylcellulose and polymethacrylates, however, the essential components of the extended release layer are the polymeric materials that give the layer its inert and non-biodegradable character. According to the invention, the polymeric materials in question are water-insoluble polymers or copolymers (but also do not form a gel when immersed in an aqueous medium) which are secreted in an intact form by the organism.These polymers can have the role of binders in the composition of the second layer, such materials are, in particular, polyvinyl chlorides, vinyl acetate / vinyl chloride copolymers, acrylonitrile / inylidene chloride copolymers, polydimethylsiloxanes and copolymers derived from methacrylic and acrylic acids. Copolymers deriving from methacrylic and acrylic acids include copolymers of methacrylic acid derivatives and copolymers of acrylic acid derivatives and methacrylic acid derivatives. Among the derivatives of methacrylic and acrylic acids esters are preferred. According to a preferred embodiment of the invention, the inert and non-biodegradable polymeric material is selected from the group consisting of the copolymers of ethyl acrylate and methyl methacrylate-, the copolymers of ethylammonium methacrylate and methyl acrylate, the copolymers of methacrylate of ethylammonium and ethyl acrylate, the copolymers of ethylammonium methacrylate and methyl methacrylate, the copolymers of ethylammonium methacrylate and ethyl methacrylate, the copolymers of methacrylic acid and ethyl acrylate, the copolymers of methacrylic acid and methyl methacrylate. According to the invention, the term "ethylammonium" refers to a radical selected from the groups of ammonium ethyl, alkyl (C? _) Ammonium ethyl, dialkyl (C?) - ammonium ethyl and trialkyl (C? -) ammonium ethyl. With ethylammonium, a trimethyl ammonium ethyl radical is preferably used. Such materials can be purchased in shops and are made, for example, by the firm Rohm.

For information purposes, the following products can be named: - Eudragit RL 30 D®, Eudragit RS 30 D®, Eudragit RL PO® and Eudragit RS PO®, Eudragit RL 12.5®, Eudragit RS 12.5®, Eudragit RL 100 copolymers ® and Eudragit RS 100®, which are copolymers of esters of acrylic acid and esters of methacrylic acid with a low content of ammonium groups.These polymers present the following recurring unit: wherein Ri represents a hydrogen atom or a methyl group and R represents a methyl or ethyl group; - the Eudragit NE 30 D® copolymer which is a neutral copolymer of ethyl acrylate and methyl methacrylate, in which the recurring unit has the formula: - Eudragit L 30 D-55® and Eudragit L100-55® copolymers with copolymers of methacrylic acid and ethyl acrylate, in which the recurring unit has the formula: - Eudragit L 100®, Eudragit L 12.5®, Eudragit S 100® and Eudragit S 12.5® copolymers are methyl methacrylic and methacrylic acid copolymers in which the recurring unit has the formula: The NE 30 D® copolymer is considered the "most convenient of these polymers." Generally, the use of methacrylic acid esters copolymers and acrylic acid esters is preferred over that of any other type of inert matrix. The molecular weight of the polymeric material used can vary greatly, depending on the nature of the monomers constituting the material.In the case of the aforementioned copolymers deriving from acrylic acid and / or methacrylic acid, the average molecular weight is between 100,000 and 1,000,000, preferably between 130,000 and 800,000.It is preferable that the amount of inert polymeric materials does not exceed 25% of the total weight of the second layer, and that it is not less than 1% of the total weight of this layer. The amount of the polymeric materials varies preferably between 2.5% and 12% of the total weight of the second layer.The tablet can be coated in its entirety with a gastro-resistant or enterosoluble polymer film so that the active ingredient is released only in the duodenal tract. The polymeric substances usually used for the preparation of the gastro-resistant systems are cellulose acetophthalate, cellulose acetopropionate, cellulose trimellitate or the polymers and copolymers of acrylic and methacrylic acids.The tablets of the invention are usually prepared by a process that includes the step-of granulation followed by a compression step In particular, the preparation process that is the object of the invention comprises the steps of: a) preparing a granulate of a first active substance from a mixture powder of the first active substance, a disintegrating agent and one or more suitable additives for preparing a layer for the immediate release of the active substance, b) preparing a granulate of a second active substance from a powdery mixture of the second substance active, one or more inert and non-biodegradable polymeric materials and one or more more suitable additives for preparing a layer for the prolonged release of the active substance; c) combining, by compression, in a known manner both types of granules obtained in steps a) and b) indicated above, in order to obtain tablets whose first layer, immediate release, results from the compression of the granulate obtained in the stage a), and whose second layer is in contact with the first layer and is obtained by compression of the prolonged release granulate obtained in stage b). The first stage (step a)) is intended to provide a granulate based on the first active substance that by compression leads to the first layer, called the immediate release layer. The second stage (step b)) is intended to provide a granulate based on the same active substance or a different active substance, which by compression forms the second layer, called the extended release layer. The components of this layer are those of the inert and non-biodegradable polymer matrix that were defined above. Step c) leads to the formation of the tablet through successive compressions of the granules obtained in steps a) and b) above. Steps a) and b) comprise the granulation of powders of amorphous or crystalline particles. This granulation is carried out in a known manner, for example, using a wet granulation process. The granulation process comprises five essential steps: (i) dry mixing of the various components, (ii) wetting, (iii) actual granulation, (iv) drying and then (v) calibration. The dry mixing consists of mixing the pulverulent excipients to make way for the composition of the granulate. Wetting consists of adding various components to the powdery mixture, a liquid that can be water, an alkanol (C? -), an aqueous solution of the binder or an alcoholic solution of the binder. According to the invention, the term "alcohol solution of the binder" encompasses both alcoholic and hydroalcoholic solutions in which the solvent is a mixture of one or more alkanols (C? _) Or a mixture of water and one or more alkanols (C ? _). A preferred alkanol (C? -) is isopropanol. The humidification is carried out in a mixer-liquefier of the kneading type, planetary, mixer, projection or vibration, or in a mixer-granulator of the rapid type. The appropriate wetting liquid in step a) is water, an alkanol (C? _4), an aqueous binder solution or an alcoholic solution of the binder as defined above, as generally recommended in the prior art.

In step b), an aqueous dispersion or an organic solution of the non-biodegradable polymeric material (s) can be used as a wetting liquid. In this way a more homogeneous distribution of the matrix is obtained. By "organic solution" is meant, according to the invention, a solution of the non-biodegradable polymeric material (s) in an organic solvent consisting of a mixture of one or more alkanols (C? ) or in a mixture of one or more ((C1-) alkyl (alkyl (C? -)) -ketones and one or more alkanols (C? _). The preferred alkanol (C? _4) according to the invention is isopropanol. Also, when a mixture of ketone (s) and alcohol (s) is employed, a mixture of isopropanol and acetone is preferred. When the polymeric material is a copolymer derived from acrylic and / or methacrylic acid, the dispersion of the solution preferably has a viscosity comprised between 10 and 300 mPa.s, more preferably between 15 and 200 mPa.s. According to a preferred embodiment of the invention, the calibration is carried out by passing through a grid with a mesh opening comprised between 0.5 and 1.5 mm, preferably between 0.8 and 1.5 mm.

The preferred size of the mesh opening is 1.25 mm in each step a) and b) However, the invention is not limited to carrying out a wet granulation process, therefore, the person skilled in the art also it can use other existing granulation processes such as the dry granulation process The last step (step c)) leads to the formation of the tablets The combination of the granulates is carried out in the usual manner and using the granulates obtained in steps a) and b) In the case of two-layer tablets containing concentric layers, this step comprises (i) the compression, carried out in a first chamber, of all the prolonged-release granules obtained in step b ) to obtain a core tablet: (ii) the compression, carried out in a second chamber, of a portion, preferably 50% by weight, of the immediate release granulate obtained in the stage a) described above; (iii) the introduction and location of the tablet core obtained in step (i) within the second compression chamber; (iv) the application in the second compression chamber of a smooth and centered compression on the core; (v) the addition of the remaining part "of the immediate release granulate to the second compression chamber, and (vi) the joint compression of the immediate release granulate on the tablet formed in stage iv) indicated above. of the two layer tablets containing parallel layers, step c) comprises: (i) a gentle compression of all the sustained release granules within a compression chamber, and then (ii) the addition of the entire release granulate Immediate to the compression chamber and its location on the tablet obtained in step (i), and (iii) the final compression of the tablet The respective proportions of the immediate release and prolonged release granules is not critical according to the invention. The tablets of the invention can be administered orally or vaginally, they allow the immediate release of a first active substance, and then the release of a second substance. active, which may eventually be equal to the first, during a period of 2 to 12 hours. The multilayer tablets of the invention are particularly convenient because their preparation process is simple and the excipients which constitute them are customary. Furthermore, "if the inert and non-biodegradable polymer materials are properly selected, the dissolution profiles can be varied within very wide ranges and with precision, depending on the needs." According to a preferred embodiment of the invention, the polymeric materials belong to the Eudragit series marketed by the firm Rohm, which are copolymers derived from methacrylic and / or acrylic acid. Thanks to the diversity of the properties of these polymers, a modulation of the release profile of the active ingredients can be achieved. In addition, these copolymers give the resulting tablets an excellent formulation capacity (possibility of incorporating high levels of the active ingredients) and compression. The choice of such copolymers also offers the possibility of coating the tablets with a film using excipients of the Eudragit type in order to obtain gastro-resistant coatings. On the other hand, these copolymers are absolutely inert in relation to the organism, which ensures the release of the active ingredient independent of the influence of the organism (and in particular of the pH variations) and, therefore, provides confidence, safety, quality , and guarantees "the reproducibility and a superior tolerance of the effects related to the administration of the tablets of the invention." The following examples will illustrate the invention in more detail: References are made to the accompanying figures 1 and 2 .

Example 1 a) Preparation and formulation of the immediate release granulate The active ingredient is 2-ethoxymethyl-4 (3H) -pteridinone, hereinafter referred to as EMP. The components for the preparation of the immediate release granulate, designated hereinafter as GLI-1, are used in the following proportions by weight: EMP 94.12% Polyvinylpyrrolidone 30 2.94% Crosslinked carboxymethylcellulose 2.94% Total 100.00% The active ingredient, polyvinylpyrrolidone 30 and carboxymethylcellulose are introduced into a mixer-granulator for 3 minutes mixing.

The wetting liquid, water subjected to osmosis, is then introduced into the granulator-mixer until well-formed granules and agglomerates are obtained. Then everything is dried (stove or fluidized air bed) and calibrated on a grid with a mesh opening of 1.25 mm. b) Preparation and formulation of the prolonged release granulate The same active ingredient as in Example 1 is used. Eudragit NE 30 D®, sold by Rohm, is used as the non-biodegradable polymer material. The components, for the preparation of the prolonged release granules, designated hereinafter as GLP-1, are used in the following proportions by weight ": EMP 71.70% Lactose fine powder 17.20% Eudragit NE 30 D® 8.80% Talc 1.10% Magnesium stearate 1.20% Total 100.00% In a mixer-granulator, the active ingredient and lactose are mixed in for 3 minutes, then the Eudragit NE 30 D®, which is an aqueous dispersion of a neutral acrylate copolymer, is progressively introduced into the mixture. ethyl and methyl methacrylate and used as wetting liquid, if necessary purified water is added to obtain well-formed granules including agglomerates, then the granulate is dried in a bed of fluidized air and calibrated on a grid with a mesh opening of 1.25 mm.

The lubricants (talc and magnesium stearate) are then mixed with the granulate obtained above for 40 seconds. c) Preparation of tablets containing concentric layers and tablets called "parallel layers" The following tablets containing parallel layers A to D are prepared by carrying out the steps indicated below and using a compression machine equipped with ovoid matrices (i) gentle compression, in a compression chamber, of the entire prolonged release granulate of Example Ib); and (ii) adding, within the same "compression chamber, all of the immediate release granulate of example la) to the tablet obtained in step (i), and (iii) subsequent compression of all the composite material by the immediate release granulate of example la) and the tablet obtained in step (i) described above The following tablet contains concentric layers E and is obtained by carrying out the steps indicated below: (a) compression, in a first compression chamber, of the entire prolonged release granulate of example Ib) to form a compressed core, (b) the compression of a fraction of the immediate release granulate of example la) in a second compression chamber (approximately half), (c) the transfer of the tablet resulting from step a) to the second compression chamber, (d) the application of a soft compression centered on the tablet of the apa a) in the second compression chamber; (e) adding the remaining part "" of the immediate release granulate of example la) into the second compression chamber; and (f) the joint compression of the immediate release granulate of example la) and of the tablet obtained in step d). Table 1 below shows the amounts of the granules that were used respectively for each tablet.

TABLE 1 Ex emp1o_ 2 _ __ Dissolution profiles of the tablets prepared according to the procedure of example 1 The dissolution profiles of the tablets made in the previous example were determined by UV spectrometry.

The tablet to be evaluated is introduced into a reactor previously loaded with one liter of water subjected to osmosis, at 37 ° C, and provided with a system for regulating the temperature and an efficient agitation system. The reactor is maintained at 37 ° C and with stirring throughout the test. At regular intervals of time t samples are taken from the medium located inside the reactor, which is filtered through a filter with a pore size of 0.45 um and analyzed by UV spectrometry.

Conditions for analysis by UV spectrometry The optical density of samples collected and diluted in a known volume of water subjected to osmosis is measured at 313 nm. The amount of the active ingredient q present in the sample is determined by comparison with the optical density of a control solution of the active ingredient, EMP, of known concentration.

By a simple calculation one can find out the total amount of the active ingredient released in the reactor at time t.

The dissolution profile of a tablet tested is obtained by plotting, on a curve, the calculated amounts of the active ingredient as a function of the collection time. The accompanying figures 1 and 2 show the dissolution profiles plotted for the case of the tablets A to E indicated above.

Example 3 The parallel layer tablets F to I listed in table 2 below are prepared following the operating protocol described in example 1.

TABLE 2 The following is the formulation of the immediate release granulate, GLI-2: EMP 91.5% Polyvinylpyrrolidone 30 4.0% Crosslinked carboxymethylcellulose 4.0% Magnesium stearate 0.5% Total 100.0% The granulates are prepared using the operating protocol of example la). The formulations of the prolonged-release granules are given below: GLP-2 _ _ EMP 71.7% Lactose fine powder 16% Eudragit RSPO 10% Talc 1.1% Magnesium stearate 1.2% Total - 100.0% GLP-3 EMP 71.7% Lactose fine powder 17.2% Eudragit RSPO Talc 1.1% Magnesium stearate 1.2% Total 100.0% GLP-4 EMP 71.7% Lactose fine powder 17.2% Eudragit RSPO Talc 1.1% Magnesium stearate 1.2% Total 100.0% These granulates are prepared using the operating protocol of Example Ib).

Example 4 The dissolution curves for the tablets F to I were plotted using the operating protocol described in example 2. These curves are shown in figures 3 to 6. It is noted that in relation to this date, the best known method The applicant for carrying out said invention is the one that is clear from the present description of the invention.

Claims (12)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Multilayer tablet for the instant and prolonged release of active substances containing at least two superposed layers, characterized in that: - a first external layer is composed of a mixture of excipients and a first active substance, allowing the first layer the immediate release of the first active substance; a second layer is in contact with the first layer mentioned above and consists of a porous, inert, non-biodegradable polymer matrix in which a second active substance is dispersed.

2. Compressed according to claim 1, characterized in that the second active substance is equal to the first active substance.

3. Compressed according to any one of the preceding claims, characterized in that the inert and non-biodegradable polymer matrix contains one or more inert and non-biodegradable polymeric materials which are selected from the group consisting of polyvinyl chlorides, vinyl acetate / chloride copolymers of vinyl, the copolymers deriving from the acrylic and / or methacrylic acids, the acrylonitrile / vinylidene chloride copolymers and the polydimethylsiloxanes.

4. Compressed according to claim 3, characterized in that the copolymers deriving from methacrylic and / or acrylic acid are selected from the group consisting of the copolymers of esters of ethyl acrylate and methyl methacrylate, the copolymers of ethylammonium methacrylate and methyl acrylate , the copolymers of ethylammonium methacrylate and ethyl acrylate, the copolymers of ethylammonium methacrylate and methyl methacrylate, the copolymers of ethylammonium methacrylate and ethyl methacrylate, the copolymers of methacrylic acid and ethyl acrylate, the methacrylic acid copolymers and methyl methacrylate.

5. Compressed according to "claims 3 or 4, characterized in that the inert and non-biodegradable polymeric materials are present in the second layer in an amount comprised between 1 and 25% by weight.

6. Compressed according to any of the preceding claims, characterized in that the porous polymer matrix contains from 1 to 95% by weight of the second active substance.

7. Compressed according to any of the preceding claims, characterized in that the first layer contains one or more disintegrating agents selected from the group consisting of alginic acid, calcium carboxymethylcellulose, sodium carboxymethylcellulose, anhydrous colloidal silica, croscarmellose sodium, crospovidone , guar gum, magnesium and aluminum silicate, methylcellulose, microcrystalline cellulose, polacrilin potassium, cellulose, pregelatinized starch, sodium alginate, sodium starch glycolate, starch and effervescent mixtures that are known in the prior art for its disintegrating action.

8. Compressed according to any one of the preceding claims, characterized in that the first layer contains from 1 to 99.0% by weight of the first active substance.

9. Two layer tablet according to any of the preceding claims, characterized in that the second layer has an upper surface and a lower surface, and only one of these surfaces is in contact with the first layer.

10. Two layer tablet according to any of the preceding claims, characterized in that the first layer and the second layer are cntric.

11. A process for preparing a tablet according to any of claims 1 to 10, characterized in that it comprises the steps of; a) preparing a granulate of a first active substance from a powdery mixture of the first active substance, a disintegrating agent and one or more suitable additives for preparing a layer for the immediate release of the active substance; b) preparing a granulate of a second active substance from a powdery mixture of the second active substance, one or more inert and non-biodegradable polymeric materials and one or more suitable additives to prepare a layer for the prolonged release of the substance active; c) combining, by compression, in a known manner both types of granules obtained in steps a) and b) indicated above, in order to obtain tablets whose first layer, immediate release, results from the compression of the granulate obtained in the stage a), and whose second layer is in contact with the first layer and is obtained by compression of the granulate obtained in stage b).

12. Compressed according to any of claims 1 to 10, characterized in that the second layer contains 2-ethoxymethyl-4 (3H) -pteridinone as active substance. SUMMARY OF THE INVENTION Multilayer tablets for the instant and prolonged release of active substances containing at least two superimposed, compressed layers characterized in that: a first outer layer is composed of a mixture of excipients and a first active substance, the first layer allowing immediate release of the first active substance; a second layer is in contact with the first layer mentioned above and is composed of a porous, inert and non-biodegradable polymer matrix in which a second active substance is dispersed. The invention also relates to a process for preparing these tablets. The present invention provides tablets that retain their release characteristics of the active substances, regardless of the conditions of administration in vivo. The tablets of the invention ensure excellent reproducibility of the results and allow a more precise control of the release rates during the prolonged release phase of the active ingredient. By using the tablets of the invention, the supply of active ingredients to the body can be optimized, taking into account both the tolerance of the subject to the active ingredient and the pharmacokinetic and metabolic profiles of the active ingredient.