MXPA97004672A - Device supplier of suspension of farmaco, control deliberation - Google Patents

Abstract

A device for the controlled release of a beneficial agent is described: the device consists of i) a core comprising at least two layers, at least one layer comprises a beneficial agent and a polymer that forms microscopic globules of gel by hydration, and at least one other layer comprising a polymer that forms microscopic globules of gel by hydration, and ii) an insoluble waterproof coating that adheres and surrounds the core and that contains openings that provide an area for hydration and release of microscopic globules. g

Description

SUPPLIER SUPPORT DEVICE OF FO I1BCO, CONTROLLED RELEASE BACKGROUND OF THE INVENTION This invention pertains to a drug delivery device, both useful and novel, for delivering a drug to a medium of use. Particularly, the invention pertains to a system capable of releasing a pharmaceutically active ingredient in a controlled manner, at a rate close to zero order. The dosage form consists of a core surrounded by an impermeable insoluble coating; the coating has openings which expose selected areas of the core to the means of use. The composition of the coating is such that the hydration of the core ingredients occurs only in the exposed portions of the core. The core is composed of at least two layers. One of these contains a pharmaceutically active compound. At least one other layer that does not contain a pharmaceutically active ingredient is also present. In each layer of the core at least one polymer is included which swells and forms gel-like globules by hydration. In the medium of use, the biological fluid contacts the exposed portions of the core surface where hydration of the exposed polymer occurs. As the polymer particles on the exposed surface absorb water, microscopic globules of gel originate. If the exposed portion of the core contains both a pharmaceutically active compound and a microscopic globule-forming polymer gel, then, as the polymer swells and moves towards the medium of use, then the pharmaceutically active compound is entrained therewith. If the exposed portion of the core contains only the polymer then only the polymer moves towards the medium of use. By incorporating holes or openings in the insoluble waterproof coating, control of the hydration rate of the polymer is achieved, and therefore the rate of release of the exposed core ingredients into the medium of use. These holes or openings expose predetermined discrete sections of the core surface. Since the exposed portion of the core surface is bonded on all sides by the coating, hydration of the polymer occurs only on the preselected exposed surface of the core. The resulting suspension of microscopic beads of gel exudes into the medium of use. The rate of release of the pharmaceutically active ingredient does not depend on the solubility of the beneficial agent in the biological fluid. Instead, the release rate depends essentially on the speed at which the microscopic gelatinous globules are formed on the exposed surface of the device and are exuded from the device, entraining the beneficial agent and any other excipient material of the nucleus that is present. . Therefore, the rate of release can be controlled by controlling the size and number of holes that the surface of the core exposes to the medium. The release rate of the pharmaceutically active ingredient also depends on the composition of the core layer exposed on the surface, at a given time. In this manner, delayed release or intermittent release can be achieved by using a core layer that does not contain the pharmaceutically active ingredient, while at the same time ensuring the complete release of the pharmaceutically active ingredient. The need for systems that can release pharmaceutically active ingredients, both soluble and insoluble, at a constant rate over a period of 4 to 24 hours is well established. Moreover, is the need for a device that is capacious? of a delayed start and scheduled release. Different approaches to this problem have been proposed. The existing technology is predominantly developed based on the controlled diffusion system that it is effective only when soluble active agents are dispensed. A further limitation of the osmotic systems consists in the need for the osmosis agent to be dosed in the presence of the swellable polymer and the inadvertent interaction between the osmosis agent and the polymer can cause an unpredictable change in the rate of release of the pharmaceutically active ingredient. . Dose forms that rely on the establishment of an extra device superstructure have also been described. Nevertheless, these can be damaged during transit in vivo, for example, in the gastrointestinal tract. If portions of the superstructure are detached, a larger surface area than desired is exposed to the medium of use and this may cause unpredictable release of the active agent. The US patent 4,814,182 describes the use of hydrogel rods or plates prehydrated and swollen polyethylene oxide. The polymer is impregnated with a biologically active agent during a hydration process. Then, the hydrated polymer is dried and partially coated with a waterproof and insoluble material. When placed in an aqueous medium, the polymer swells but does not dissolve or disintegrate. The trapped active ingredient is released from the polymer by diffusion. The release mechanism relies on the ability of the soluble drug to diffuse through the rehydrated hydrogel and move into the aqueous medium. The US patent. 4,839,177 describes the use of compressed hydrogels to define geometric shapes that are mixed with biologically active ingredients wherein a portion of the device is fixed to a "support platform" made of an insoluble polymeric material. When the inflatable and gellable hydrogel is hydrated, it expands beyond the device and establishes a superstructure from which the active agent is released either by diffusion, if the active agent is soluble, or by erosion, if the active agent is insoluble. The generation and maintenance of the superstructure is vital to the success of this device. In the patent of the US. No. 4,971,790 describes an osmotic dose form utilizing a semipermeable wall containing at least one "exit medium" that passes through the wall, surrounding a core containing an osmotic agent, a neutral and ionizable hydrogel, and an active ingredient. active. The coating of this device is permeable to water from the medium of use. Water moves towards the core through the semipermeable membrane. Once inside the device, the water solubilizes the osmotic agent and the ionizable hydrogel. Pressure is formed inside the device, due to the ionization of the osmosis agent. Finally, the solubilized ionizable hydrogel containing the beneficial agent, the neutral hydrogel and other excipients of the core, are pumped out of the core, through an outlet means and into the means of use. The US patent. No. 4,915,954 describes a device having a two-layer core. One layer is released faster than the other and is composed mainly of a mixture of hydroxypropylcellulose and hydroxypropylmethylcellulose. The lower layer can also be made of cellulosic polymers but of different or higher molecular weight. This slower layer also contains a hydrogel, preferably polyethylene oxide. This device requires a semipermeable wall. In Example 4 and Figure 7 of the description the need for control of the thickness of the wall (or wall weight) and its effect on the permeability, and subsequently on the release, is shown. Wall thickness control is one of the main negative characteristics of osmotically controlled release devices. European Application 0 378 404 02 describes a microporous coating on an osmotic hydrogel core. This device comprises a coating through which the pharmaceutically active agent can pass when the device is exposed to an aqueous medium. Like other discussed devices, wetting, hydration or solubilization of the core material by the imbibition of fluid through the coating must occur for this device to function. The US patent. 5,356,738 describes a device consisting essentially of a compressed homogeneous core prepared from a mixture comprising a therapeutically effective amount of a pharmaceutically active ingredient and polymer that forms microscopic gelatinous globules by hydration. This core is coated with a polymeric coating insoluble in water and impermeable to water, which surrounds and adheres to the core, the coating has a plurality of openings, exposing between about 5 and about 75% of the core surface. Although these dosage forms provide a means to control the release of an insoluble pharmaceutically active ingredient, delayed release is not provided. The utility of the above devices could be increased if a device and method is provided to improve the release of pharmaceutically active ingredients, at a constant rate, and if a medium for delayed release of the pharmaceutically active ingredient is also possible. Further improvement will be made if a dosage form that provides intermittent release of the pharmaceutically active ingredient is provided.

BRIEF DESCRIPTION OF THE INVENTION A drug delivery device is described for in situ production and release. of a suspension containing a beneficial agent, consisting essentially of: fl) a compressed core comprising at least two layers; at least one layer comprises a mixture of a therapeutically effective amount for those in need thereof, of a pharmaceutically active ingredient and a polymer which by hydration forms microscopic, gelatinous globules; and at least one other layer comprising a polymer which by hydration forms gelatinous microscopic globules;, and B) a polymeric coating impermeable to water and insoluble to water applied to the core, which surrounds and adheres to the core; the coating has openings, exposing between about 5 and about * 75% of the core surface.

DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of one embodiment of the present invention. The insoluble waterproof coating (10) completely surrounds the device. Openings (11) are provided for defined sites where the hydration of the core surface occurs, once the dosie form is placed in the medium of use. The core is composed of a central layer (14) and two outer layers (13). The central layer (14) comprises both the pharmaceutically active ingredient (15) and the polymer (16) which, by hydration, swells and forms gelatinous globules. The outer layers of the core (13) contain the polymer (16) but not the pharmaceutically active ingredient. Figures 2 and 3 are schematic representations of a further embodiment of the core of the present invention wherein a tablet (20) containing the pharmaceutically active ingredient (15) and the polymer (16) which by hydration swells and forms gelatinous globules , is compressed within a shell (21) of inert material comprising the polymer (16). Figure 4 is a schematic representation of a preferred embodiment of the core of the present invention wherein a two-layer core is used. In this embodiment, a core layer comprises both the pharmaceutically active ingredient (15) and the polymer (16), while the other core layer comprises the polymer (16). Figure 5 is a graph of the release of the pharmaceutically active ingredient from two configurations of the present invention and a comparison of the release from a homogenous core device having the same number of holes in the coating.

DETAILED DESCRIPTION OF THE DRAWINGS During the operation, aqueous solution of the medium of use makes contact with the surface of the core which is exposed within the openings (11). The available water begins to hydrate the polymer forming microscopic globules of gel (16) on the surface of the core. If present, the polymer hydration modulating agent (not shown), on the exposed core surface, solubilizes and establishes the required medium for controlled hydration of the polymer. fll hydrate the polymer (16), exudes from the surface as microscopic globules gelatinous. Finally, hydration originates from the middle layer (14) present on the surface where the particles of the beneficial agent (15) are extracted from the surrounding surface. These beneficial agent particles (15) move from the surface of the core in contact with the medium of use in a suspension with the gelatinous microscopic globules of the hydrated polymer (16). If openings are drilled on both sides or faces of the device, hydration can continue from each side simultaneously. Alternatively, when the openings are drilled only on one side or face of the device, hydration occurs first in the outermost layer of the openings, then in the central layer (14) and finally in the outer layer far away from the openings. When the hydration of this layer occurs, the polymer gelatinous globules exude from the device through the openings and in doing so inflate the remaining contents of the middle layer (14) of the core and into the medium of use. This swelling effect results in an extension of the zero order release rate and allows efficient release of the pharmaceutically active ingredient. Figures 2, 3 and 4 are defined throughout this document. Figure 5 is a graph of the pharmaceutically active ingredient released over time from two configurations of the present invention, and a comparison with a normal homogeneous core device with the same hole configuration.

DETAILED DESCRIPTION OF THE INVENTION The novel drug delivery device of this invention provides the controlled production and release of a suspension containing a beneficial agent, comprising: (A) A compressed core comprising at least two layers; at least one layer comprises a mixture of a therapeutically effective amount for those in need thereof, of a pharmaceutically active ingredient and a polymer which by hydration forms microscopic, gelatinous globules; and at least one other layer comprising a polymer that by hydration forms microscopic, gelatinous globules; Y (B) A water-impermeable polymeric coating, insoluble in water, which surrounds and adheres to the core; the coating has openings exposing between about 5 and about 75% of the core surface. By "drug spout device" is meant a dosage form that provides a convenient means of releasing a pharmaceutically active ingredient or drug to a subject in need thereof. The subject may be human or any other animal in need of said pharmaceutically active ingredient. The device is designed to be used in the release of the pharmaceutically active ingredient by means of any pharmaceutically accepted means such as by swallowing, retaining it within the mouth until the beneficial agent is delivered, placing it within the buccal cavity, or the like. . By "controlled production in situ" it is meant that the rate of release of the pharmaceutically active ingredient, which is the amount of the pharmaceutically active ingredient released from the device into the medium of use, follows a predetermined pattern. In this way, relatively constant or predictable amounts of the beneficial agent can be delivered over a specified period. By "pharmaceutically active agent" is meant any compound commonly referred to as a "drug" and its equivalents which include any physiologically or pharmacologically active substance that produces a localized or generalized effect or effects on animals. The term "animal" includes mammals, humans and primates, such as domestic, home, sport or farm animals such as goats, sheep, cattle, horses and pigs, laboratory animals such as mice, rats and guinea pigs, fish, birds, reptiles and zoo animals. The pharmaceutically active ingredients that can be released by means of the novel device of this invention include inorganic and organic compounds without limitation, including drugs that act on the peripheral nerves, adrenergic receptors, cholinergic receptors, nervous system, skeletal muscles, cardiovascular system, muscles. smooth, blood circulatory system, synaptic sites, neuroeffector binding sites, endocrine and hormonal systems, immune system, reproductive system, skeletal system, a tachoid system, food and excretory systems, inhibitory and histamine systems; and those materials that act on the central nervous system such as hypnotics and sedatives. Examples of pharmaceutically active ingredients are described in Remington's Pharmaceutical Sciences, 16i Ed., 1980, published by Mack Publishing Co., Eaton, Pa. And The Pharmacological Basis of Therapeutics, by Goodman and Gilman, 61 Ed. 1980, Published by The MacMillan Company, London and in Merck Index, lli Ed, 1989, published by Merck ft Co., Rahway,. 3. The dissolved drug may be in different forms, such as charged molecules, charged molecular complexes or ionizable salts. Acceptable salts include, but are not limited to, hydrochlorides, bromide, sulfate, laurilate, palmitate, phosphate, nitrate, borate, acetate, maleate, malate, troethamine, tartrate, oleate, salicylate, metal salts, and amines. organic cations, for example quaternary ammonium. Derivatives of pharmaceutically active ingredients such as esters, ethers and amides regardless of their ionization and solubility characteristics may be used alone or mixed with other compounds. Also a pharmaceutically active ingredient can be used in a form that by releasing the device is converted by means of enzymes, hydrolyzed by the pH of the body, or other metabolic processes, to the original form, or to a biologically active form. That is, the prodrugs are specifically included within the definition of pharmaceutically active ingredients. Specific examples of pharmaceutically active ingredients which can be adapted for use include barbiturates such as sodium pentobarbital, phenobarbital, secobarbital, thiopental and mixtures thereof; heterocyclic hypnotics such as dioxopiperidines and glutarides; hypnotics and sedatives such as amides and ureas, exemplified by diethyl isovaleramide and a-bromoisovaleryl rea; urethanes and hydrophobic and sedative disulfones; psychic energizers such as isocarboxazide, nialamine, imipramine, aminitriptiline hydrochloride, pargylene, and protriptyline hydrochloride; tranquilizers such as chlorpromazine, promazine, fluphenazine, reserpine, reserpine, and eprobarnate; benzodiazepines such as diazepa and chlordiazepoxide; anticonvulsants such as pri idone, phenytoin and ethoxysuccimide; muscle relaxants and antiparkinson agents talee co or efenisin, methocarbamol, cyclobenzaprine chlorhirate, trihexylphenidyl hydrochloride, levodopa / carbidopa, and biperidine; antihypertensives such as co-a-methyldopa and the tivaloyloxyethyl ester of α-methyldopa; blockers of the calcium channel such as nifedipine, diltiazem hydrochloride, diltiazem malate and verapamil hydrochloride; analgesics such as morphine sulfate, codeine sulfate, eperidine and nalorphine; antipyretic agents and amphiphilic agents such as aspirin, indornethacin and ibuprofen, indo-acetic acid sodium trihydrate, salicylamine, naproxen, colchicine, fenoprofen, s? lindac, diflunisal, diclofenac, indoprofen and sodium salicylamide; local anesthetics such as procaine, lidocaine, tetracaine and dibucaine; Odic antispasms and muscular contractors such as atropine, scopolamine, methylcopolamine, oxy enonium, papaverine; prostaglandins such as PGEi, PGE2, PGE2 *; antimicrobial and antiparasitic agents such as penicillin, tetracycline, oxytetracycline, chloramphenicol, thiabendazole, ivermectin, and s? lfonamides; antimalarials such as 4-aminoq? inolines, 8-amino-q? inolines and pyrimethamine; hormonal and steroidal agents such as dexa etasone, perednieolone, cortisone, cortisol and triamcinolone; androgenic eteroteroids such as methyltestosterone; estrogenic steroids such as 17α-estradiol, α-estradiol, estriol, α-estradiol 3-benzoate and 3-methyl ether of 17-ethynyl estradiol and progestational steroids such as progesterone; drugs if paticomimetics such as epineprin, phenylpropanolamine hydrochloride, amphetamine, ephedrine and norepinephrine; hypotensive drugs talee such as hydralazine; cardiovascular drugs such as procainamide hydrochloride, amyl nitrite, nitroglycerin, dipyridamole, sodium nitrate and mannitol nitrate; diuretics such as chlorotriazide, acetazolarnide, metazole ida, hydrochlorothiazide, amiloride hydrochloride and flumetiazide, sodium ethacrylate and f? rose ida; antiparasitic agents such as befenium, idro inaftoate, dichlorophen and dapsone; antineoplastics such as mechlorethamine, uracil mustard, 5-fluorouracil, 6-thioginane and procarbazine; 0-blockers talee as pindolol, propranolol, metoprolol, oxprenolol, timolol maleate, atenolol; hypoglycemic drugs such as insulin, isophane insulin; insulin protamine zinc, zinc globin insulin, prolonged suspension of zinc insulin, tolbuta ida, acetohexamide, tolazamide and chlorpropamide, antiulcer drugs such as cytidine, ranitidine, famotidine and omeprazole; nutritional agents such as ascorbic acid, niacin, nicotinamide, folic acid, choline, biotin, pantothenic acid; essential amino acids; essential fats; ophthalmic drugs such as timolol maleate, pilocarpine nitrate, pilocarpine hydrochloride, atropine sulfate, scopolamine; electrolytes such as calcium glucanate, calcium lactate, potassium chloride, potassium sulfate, sodium sulphide, ferrous lactate, ferrous gluconate, ferrous sulfate, ferrous fumarate and sodium lactate; and drugs that act on alpha-adrenergic receptors such as clonidine hydrochloride; analgesic drugs such as acenophene acetyl, oxycodone, idrocodone, and propoxyphene; antihypercholesterolearic drugs such as simvastatin, pravastatin, lovastatin and genfibrozil; anti-infective drugs such as cefoxitin, cefazolin, cefotaxime, ciprofloxacin, cephalexin, norfloxacin a, prolio, ampicillin, amoxicillin, cefaclor, erythromycin, nitrofurantoin, inociclin, doxycycline, cefadroxil, miconazole, clotrimazole, phenazopyridine, clorsyl, fludalanin, pentizidone, cilastine, phosphine iciña, imipenem; gastrointestinal drugs such as bethanechol, clidinium, dicyclomin, meclizine, prochloperizine, tri-ethobenzamide, loperamide, diphenoxylate, and ethoclopramide; anticoagulant drugs such as warfarin, phenindione, and anisindione; and other drugs such as trientine, cambendazole, ronidasol, rafoxinide, dactinomycin, asparaginase, nalorphine, rifamycin, carbamazepine, etaraminol bitartrate, allopurinol, probenecid, hydrogenated rye meat alkaloids, nystatin, pentazocine, phenylpropanolamine, phenylephrine, pseudoephedrine, trimethoprim, and ermectin. The above list of drugs does not mean that it is exhaustive. Many other drugs will undoubtedly work in the present invention. By "compressed core comprising at least two layers" is meant a mixture of ingredients comprising a beneficial agent, a polymer that produces microscopic globules of gel when hydrated, and other ingredients that can affect any of (1) the speed of production of the suspension, (2) the stability of the components of the dosage form or (3) the characteristics of mixture or compression of the mixture, which are mixed in such a way as to produce a uniform product. This uniform product is then compressed, within a matrix, to produce a desired shape, usually in the form of a tablet. This pressed product constitutes at least one layer of the compressed core. Also, a second mixture of ingredients comprises a polymer that produces microscopic globules of gel when hydrated, and other ingredients that can affect any of (1) the production rate of the suspension, (2) the stability of the components of the dosage form or (3) the mixing or compression characteristics of the mixture, which are mixed in such a way as to produce a uniform product. This uniform product is then pressed into a matrix to produce a desired shape, usually in the form of a tablet. This pressed product constitutes at least the additional layer of the compressed core. The "compressed core comprising at least two layers" can be produced manually or using automated equipment as described herein. In addition, the "compressed core comprising at least two layers" can be manufactured using a plastic tableting machine such as that produced by Manesty Machines Limited. The "compressed core" can have more than two layers. In one embodiment of this invention, the compressed core is made of three layers. The middle layer contains both pharmaceutically active ingredient and polymer which by hydration forms microscopic gelatinous globules, as well as other excipients useful in the production, dissolution and release of the layer. Also present in this preferred embodiment, an upper and lower layer, which are adjacent to and above and below the middle layer, each contains a polymer which, by hydration, forms microscopic gelatinous globules, as well as other useful excipients in the production, dissolution and release of the layer. In this configuration, the upper and lower parts of the core are identical, which are already known as the upper or lower face of the core. As a result, when drilling openings or holes in only one side of the core, as in the preferred embodiment, the exact orientation of the core need not be considered. That is, since both the upper and lower part of the core are identical, the openings can be drilled on any face regardless of the orientation of the tablet. This results in a faster treatment of the device during the drilling process and also introduces a programmed time delay in the release of the pharmaceutically active compound. The compressed core contains "a therapeutically effective amount" of beneficial agent and a polymer that by hydration produces microscopic globules of gel. By "therapeutically effective amount" is meant the amount of pharmaceutically active ingredient that has been shown to be sufficient to induce the desired effect during studies using the compound. Other excipients such as lactose may also be present in the core layers., magnesium stearate, microcrystalline cellulose, starch, stearic acid, calcium phosphate, glycerol monostearate, sucrose; polyvinylpyrrolidone, gelatin, methylcellulose, carboxy atilcelulose sodium, sorbitol, mannitol, polyethylene glycol and other ingredients commonly used as stabilizing agents or to aid in the production of tablets. The pharmaceutically active ingredient can be in a core layer as a dispersion, particle, granule or powder. Also the pharmaceutically active ingredient can be mixed with a binder, dispersant, and ulsifier or wetting and coloring agent. The pharmaceutically active ingredient may comprise from about 0.01% to about 75% of the weight of the core. Generally, the dispensing device can accommodate from about 0.05 ng to about 5 grams of active agent or more, with individual devices containing, for example, 25 ng, 1 mg, 5 mg, 250 g, 500 mg, 1.5 g, or similar. . The "polymer that by hydration forms gelatinous icroglóbuloe" useful in the novel device of this invention broadly encompasses any polymer that by hydration is capable of producing discrete microscopic globules of gel that support a suspension, including the beneficial agent, as formed. The gel-forming polymer used must also exude from the surface of the core in such a way that the beneficial agent is drawn into the medium of use. By hydration, the gelatinous microbeads must be predisposed to leave the surface that the drug takes with it. This ensures a constant surface area exposed to the solvent of the medium of use and maintains the proper release rate. The "gelatinous microscopic globules" are composed of discrete particles of hydrated polymer. Both the size and the rate of hydration of these microscopic gel globules are characteristic of individual polymers. Illustrative of this type of polymer are "flOUAKEEP J-550", "AQUflKEEP J-400", which are acrylate sodium acrylate polymer labels produced by Seitetsu Kagaku Co., Ltd., Hyogo, Japan. The "OOUAKEEP" polymers are generically described in U.S. Pat. No., 340,706. Also illustrative of this type of polymer are carboxypolymethylenes prepared from acrylic acid crosslinked with allyl ethers of sucrose or pentaerythritol and sold under the trademarks "CARBOPOL 934P" and "CARBOPOL 974P", trade names of two carbonaceous type polymers produced by B.F. Goodrich Chemical Company, Cleveland, Ohio. Carbomer polymers are generally described in U.S. Pat. 2,909,462 and in the National Formulary XVII on p. 19911, CRS Registry Nurnbre 9003-01-4. All of the above references are incorporated herein by reference. In the dry state, the particles of "CARBOPOL 974P" and "CARBOPOL 934P" vary in size from 2 to 7 microns. When these particles are hydrated, microscopic globules of gel are produced in the scale of 20 microns. When the particles "AQUAKEEP J-550" or "AOUAKEEP J-400" are hydrated, the diameter of the microscopic globules of gel can vary in size from 100 to 1000 microns. The "hydration modulating polymer" useful in the novel device of this invention broadly encompasses any water-soluble compound that can inhibit or increase the hydration rate of the core gel-forming polymer. Among the groups of compounds that can exert this effect are acids, bases, and the salts of acids and bases such as adipic acid, citric acid, fumaric acid, tartaric acid, succinic acid, sodium carbonate, sodium bicarbinate, betamine hydrochloride , sodium citrate, arginine, meglamine, sodium acetate, sodium phosphates, potassium phosphates, calcium phosphate, ammonium phosphate, magnesium oxide, magnesium hydroxide, sodium tartrate and tro etamine. Other compounds that can be used as the hydration modifying polymer include sugars such as lactose, sucrose, mannitol, sorbitol, pentaerythritol, glucose and dextrose. Polymers such as raicrocrystalline cellulose and polyethylene glycol as well as surfactants and other organic and inorganic salts can also be used to modulate the hydration of the polymer. The hydration modulating agents are solubilized by the aqueous medium of the medium and establish a medium such that the pH, ionic strength or hydrophilic character are appropriate for the desired hydration rate of the microscopic polymer gel globule. For example, these hydration modulating agents can increase or retard the neutralization of acid functional groups on the polymer which affects the rate of hydration. The core compartment containing the drug, the hydration modulator and the microscopic globule-forming polymer gel, as described herein, is typically in the form of a conventional solid tablet. The core layers may contain auxiliaries and compression diluents such as lactose which aid in the production of compressed tablets. The core layers can be compressed from a mixture of combined agents to give the desired manufacturing and release characteristics. The number of agents that can be combined to make the core does not substantially have an upper limit and the lower limit is equivalent to two components: the gel-forming polymer and the beneficial agent. The preferred specifications for the layer containing the pharmaceutically active ingredient of the core are summarized as follows: 1.- Charge of the drug in the core (size): 0.01% to 75% by weight of the total mass of the core or 0.05 nanograms to 5 grams or more (include dosage forms for humans and animals). 2.- Polymer hydration modulator: 0% to 75% by weight of the total mass of the core. 3.- Gel-forming polymer: 5 to 75% by weight of the total mass of the core. The preferred specifications for the layer q? E does not contain a pharmaceutically active ingredient are summarized as follows: 1. Gel-forming polymer: 5 to 75% by weight of the total mass of the core. 2.- Polymer hydration modulator: 0 to 75% by weight of the total mass of the core. In another preferred embodiment of the core of this invention, a tablet comprising the pharmaceutically active ingredient and the gel-forming polymer is first compressed and then inserted into a larger external inert tablet comprising the gel-forming polymer but without pharmaceutically active agent. This results in a device comprising an inner tablet compressed in an inert shell of a gel-forming polymer, exposing one face of the inner tablet. This modality is shown in Figures 2 and 3.

Figure 2 is a top view of the finished dosie form showing the inner tablet (20) which comprises both the pharmaceutically active ingredient and the gel forming polymer and the larger inert outer tablet shell (21) . Figure 3 shows a side view of the same embodiment, and it can be seen that one face (22) of the inner tablet (20) is exposed to the environment while the edges (23) and the remaining face (24) of the the inner tablet (20) are surrounded by the largest inert external tablet (21). Such embedded tablets can be produced manually by compressing the tablet comprising both the pharmaceutically active ingredient or the gel-forming polymer and placing it in a matrix containing the granulation of the larger outer inert tablet and compressing again. In practice, the matrix used to produce the final embedded tablets should be at least 0.23 c larger in diameter than the matrix used to produce the internal tablet. In general, the matrix used to compress the final core is about 0.08 cm to about 0.41 cm larger in diameter than the matrix used to produce the inner tablet. Automated equipment such as Manesty Drycoater can be used to produce these tablets. This equipment is available from Thomas Engineering, Hoffman Estates, IL 60195 or Manesty Machines Limited, Evans Road, Speke, Liverpool L249L0 England. Once the core is prepared, it can be coated and drilled in the manner described. Depending on the speed and the desired profile of release of the acetic active ingredient, the holes can be placed on both sides of the device or only on one side. Similarly, it may be convenient to drill the holes so that only the portions of the face of the inner tablet are exposed. In the preferred embodiment of the core of this invention, a two-layer core is used. In this embodiment, which is shown in Figure 4, a layer (30) comprises the pharmaceutically active ingredient and the gel-forming polymer, while the inert layer (31) comprises the gel-forming polymer and not the pharmaceutically active ingredient. These nuclei can be prepared by manually filling a matrix with the granulation containing the active ingredient by manually comparing this layer with a flat-faced punch or normal concave punch preferably with no more than 225 kg of compression force, using a Laboratory Press Model C engraver. , or using a Stokes F Press Model 519-2. Then, the inert granulation is filled in the matrix on top of the layer containing the active ingredient and is compressed sufficiently to give a hard core which is then coated using the following procedure. The two-layer cores produced in this manner can be coated and drilled using any of the described methods. However, if it is desired to have openings on only one side of the device, some identification mechanism must be used so that the face containing the pharmaceutically active ingredient can be distinguished during the drilling operation. The faces are easily distinguished by composition or color thereby allowing a detector to identify the proper face for the drilling operation. Said detectors for this purpose can use photoacoustic spectroscopy, infrared and near-infrared spectroscopy, UV and visible spectroscopy, fluorescence spectroscopy, agnetrometry and any other suitable technique known to those skilled in analytical chemistry. In cases where the pharmaceutically active ingredient, the gel-forming polymer and the polymer hydration modulating agent exhibit the desired characteristics of release rate, stability and manufacture, the upper or lower limit on the amount of ingredient is not critical. pharmaceutically active that can be incorporated into a core layer. The ratio of drug to excipient is governed by the time lapse and release profile desired.,, and the pharmacological activity of the drug. Generally, the layer containing the pharmaceutically active ingredient of the core will contain about 1% to about 50% by weight of a beneficial agent mixed with other solutes. Representative compositions of matter that can be released from the device and can function as a solute are, without limitation, those compositions as described. The coating, applied to the core of the invention, is a material that is impermeable and insoluble in the medium of use, can form films, and does not adversely affect the acetically active ingredient, the animal body or the host. The coating is impermeable to water and also impermeable to the selected product, drugs, polymer hydration modulating agents,? other compounds in the device. This impervious material is insoluble in body fluids and is not disintegrable or can be biodegradable after a predesigned period with biodisintegration after the end of the active drug release period. In each case it is impermeable to the solvent and solutes found in the medium of use and is suitable for the construction of the device. The polymeric coating is applied and adheres to the entire surface of the core. Openings in the coating are cut to expose the core, using either a mechanical or laser drill, a core device, or any other pharmaceutically acceptable means. In one embodiment, a mechanical drill is used to produce the openings. In another embodiment, a laser is used to make the openings.

The openings allow the solution to contact only exposed portions of the core when in use. The number, size and configuration of the openings are chosen to provide the release rate required to adapt to a pharmacologically recognized requirement since the hydration of the polymer occurs only where the openings allow such core-solvent contact. The coating can be applied by immersing the cores in a suitable solution of the polymer or by spray coating the cores with the polymer solution. Among the polymers that can provide this type of protection are cellulose acetate butyrate and polyvinyl chloride. In addition, other materials such as plasticizers may be included with the coating to increase their stability, color, elasticity, ease of application or opacity, as long as these ingredients do not reduce the impermeability or insolubility of the coating. Similarly, compounds such as triethyl citrate can be added to the coating. The coating is typically applied to a thickness of from about 1 to about 1000 microns, but preferably from about 10 to about 500 microns, although thinner or thicker coatings fall within the scope of this invention. The term "aperture", as used herein, refers to doors through the coating that expose the surface of the core to the medium. The size and number of openings are chosen to achieve the desired release rate. To determine the number and size of the aperture, the rate of hydration of the gel-forming polymer, the type and concentration of the polymer hydration modulating agent used in the core and the ability of the beneficial agent to form ions should be considered. The openings are generally placed in a regular pattern on both sides of the device although they can be placed anywhere on the core, including the edges or as previously described, on one side. The openings are generally circular but can be of any design that results in the proper release rate. When the opening is circular, its diameter varies from about 0.1 mm to about 5 mm, with typical diameters of about 0.3 to about 3.5 mm. One embodiment of the impermeable wall includes a mixture of eight parts by weight of cellulose acetate butyrate, two parts by weight of cellulose acetate and one part by weight of diethyl phthalate. This mixture is dissolved in a solution of methylene chloride and methanol (3: 1 v / v) and applied by spraying on the cores to a thickness of approximately 250 microns. Another preferred coating consists of five parts by weight of cellulose acetate butyrate and one part by weight of triethyl citrate dissolved in a mixture of acetone and methanol (3: 1 v / v). This mixture is applied by spraying on the core, or the cores are submerged in the mixture so that a coating of 100 microns is applied. In a preferred embodiment of the impermeable wall, a mixture of 10 parts by weight of cellulose acetate butyrate and one part by weight of triethyl citrate is used. This 3% w / v mixture is dissolved in a solution of acetone and ethanol (3: 1 v / v), or methylene chloride and methanol (3: 1 v / v) and applied by spraying on the cores to a thickness of approximately 100 microns. The polymers used in the coating that are described herein are known in the art or can be prepared according to the procedures of the Encyclopedia of Polymer Science and Technology, Vol. 24 published by Interscience Publishers, Inc., New York, from Handbook of Common Poly mers of Scott, J.R. and Roff, U.J., 1971 published by CRC Pr ss, Cleveland, Ohio. The following examples illustrate the preparation of the drug spraying device of this invention and its controlled release of "no or more therapeutically active ingredients into a medium of use, and as such are not considered to be limiting of the invention set forth in the appended claims.

EXAMPLES EXAMPLE 1 Two-layer cores were inoculated, wherein one layer contained a pharmaceutically active ingredient and a polymer which by hydration forms microscopic gelatinous globules and a second layer which does not contain the active acetic acid ingredient, as a means to improve the extent of the release of a single layer core containing the pharmaceutically active ingredient and polymer. The layer containing the pharmaceutically active ingredient was twice the weight of the inert layer. The layer of the pharmaceutically active ingredient contained lovastatin, (40 mg / layer), CARBOPOL 974P (16 mg / layer), trisodium citrate (32 mg / layer), and lactose (16 mg / layer). The cores were coated with the impermeable wall of a mixture of 20 parts by weight of cellulose acetatebutyrate and 3 parts by weight of triethyl citrate. This mixture, at 3% w / v, was dissolved in a solution of acetone and ethanol (3: 1 v / v) and applied by spraying on the cores to a thickness of approximately 100 microns, using a Freudn Model HCT-Mini Hi-Coater fbombo). Two hole configurations were evaluated: 39 holes of 0.5 m drilled in the face of the device (See Fig. 5, # 53), which allowed the exposure of the core layer containing the pharmaceutically active ingredient, and 22 holes of 0.5 mro on the face of the device (See Fig. 5, # 51) adjacent to the layer q? e contained the pharmaceutically active ingredient. The performance on the in vitro release rate of both groups of devices was measured at 37 ° C in isotonic regulatory solution at pH 7.4 containing 0.4% w / w of sodium dodecyls? Lphate using a USP Apparatus II at 50 rpm. The cumulative percentage of lovastatin released against time is plotted and shown in Figure 5, using single composition core devices with 39 holes of 0.5 mm (Fig. 5, # 52) and 22 holes of 0.5 mm (Fig. 5, # 51) as patterns. As shown in Figure 5, the release profiles for the two-layer device improved significantly over the core of a single composition, since at least 20% of lovastatin was released at a more constant rate and greater than 95% of the content of lovastatin that was released in less than 20 hours. This is an improvement of 10 to 15% in the cumulative percentage released on the core device of a single composition.

EXAMPLE 2 Tablets were prepared for the controlled release of nifedipine from the following formulation: Ingredients: Active Layer g / Layer Nifedipine icronized 33"CARBOPOL 974P" NF 15 Dibasic sodium phosphate (anhydrous) USP 37.5 Lactose anhydrous NF (spray-dried) 7.5 Povidone USP K-90 2. 5 Magnesium stearate NF 0 5 96. 0 Ingredients: Inactive layer mg / Capa AVICEL PH101 33"CARBOPOL 974P" NF 15 Sodium citrate dihydrate USP 37.5 Lactose Hydrate NF (impalpable) 7.5 Povidone USP K-90 2.5 Magnesium stearate NF 0.5 96.0 The micronized nifedipine was combined with sodium dibasic phosphate, CARBOPOL, lactose and polyvinypyrrolidone, mixed uniformly and then granulated using an aqueous mixture of alcoholic solvent (10% by volume of water). The solvated mass was passed through a # 20 mesh and then dried initially at 60 ° C for 2 to 4 hours, then at 40 ° C overnight. Magnesium stearate was sieved over the dry granulation and the total mixture passed through a # 40 mesh. The same procedure was used to prepare the inactive granulation, with AVICEL instead of nifedipine. The active granulation was first filled into a normal concave round matrix of 0.71 cm and compressed with a force of 90 to 360 kg; after, the inactive granulation was filled on the lightly compressed active layer and the two layers were compressed together with a force of 665 to 900 kg. The resulting thickness was 4.3 rnm and the hardness was 18 kg. Tablets were coated to a thickness of 100 microns with the following coating formulation using a fl uidized column sprayer coater, Uniglat Fl? Idized.

Ingredients of the coating of the film Quantity Cellulose acetate butyrate (Eastman 381-20) 140 g Triethyl citrate NF 14 g Methylene Chloride 3000 ml Alcohol USP 1000 rnl The tablets were mechanically drilled with 16 openings of 0.45 m in diameter, through the coating on the active face. In vitro release tests were carried out 37 ° C using USP Apparatus II in phosphate buffer pH 7.4 containing 2% sodium dodecylsulfate at 100 rpm. The drug released was analyzed by spectrophotometry UV continuous flow at 340 nm. The results of this study are shown in figure 6. 2 or 3 tablets can be filled in a gelatin capsule to provide dosages of 60 or 90 mg.

Claims (23)

NOVELTY OF THE INVENTION CLAIMS

1. - A drug delivery device for the production and controlled release in situ of a suspension containing a beneficial agent, consisting of: a) a compressed core comprising at least 2 layers, wherein at least one layer comprises a mixture of a therapeutically effective amount for those in need thereof, of a pharmaceutically active ingredient and a polymer which by hydration forms microscopic, gelatinous globules; and at least one other layer comprising a polymer that by hydration forms microscopic, gelatinous globules; and b) a water-insoluble, water-insoluble polymeric coating that is applied to the core, which surrounds and adheres to the core; the coating has openings exposing between about 5 and about 75% of the core surface.

2. The device according to claim 1, further characterized in that the polymer is selected from sodium acrylate acrylate and the acrylic ethers of sucrose or pentaerythritol and pharmaceutically acceptable salts thereof.

3. The device according to claim 1, further characterized in that the amount of beneficial agent in the core comprises from about 1% to about 75% by weight of the core mixture.

4. The device according to claim 1, further characterized in that the beneficial agent is an inhibitor of HMG-CoA reductase.

5. The device according to claim 4, further characterized in that the beneficial agent is selected from the group consisting of lovastatin, pravastatin and if vastatin.

6. The device according to claim 1, further characterized in that the beneficial agent is lovastatin.

7. The device according to claim 1, further characterized in that the beneficial agent is nifedipine.

8. The device according to claim 1, further characterized in that the amount of polymer, which by hydration produces microscopic gelatinous globules in the core comprises from about 75% to about 10% by weight of the core mixture.

9. The device according to claim 1, further characterized in that the mixture of the core comprises a polymer hydration modulating agent selected from the group consisting of acids, bases, salts, sugars, surfactants and soluble polymers.

10. The device according to claim 9, further characterized in that the sß polymer hydration modulating agent is selected from the group consisting of sodium citrate, beta-inahydrochloride, sodium bicarbonate, sodium carbonate and arginine.

11. The device according to claim 1, further characterized in that the water-insoluble coating is selected from polyvinyl chloride, cellulose acetate, cellulose acetate or ethylcellulose.

12. The device according to claim 1, further characterized in that the openings in the coating vary in diameter from about 0.5 mm to about 2 mm.

13. The device according to claim 12, further characterized in that the openings are arranged in an irregular pattern around the surface of the device.

14. The drug delivery device according to claim 1, for the production and controlled release in situ? of a suspension containing nifedipine, consisting essentially of: a) a compressed core comprising a first layer, and a second layer, the first layer comprising a therapeutically effective amount for those in need thereof, of a pharmaceutically active ingredient active and? n polymer that forms microscopic gelatinous globules by hydration; a second layer comprising a polymer that forms microscopic gelatinous globules by hydration; and b) an insoluble waterproof polymeric coating that surrounds and adheres to the core and contains openings exposing between about 10% and about 75% of the core surface.

15. The drug delivery device according to claim 14, further characterized in that the polymer is CARBOPOL 974P.

16. The drug delivery device according to claim 14, further characterized in that the insoluble impermeable polymeric coating comprises cellulose acetatebutyrate and triethyl citrate.

17. The drug dispensing device according to claim 14, further characterized in that it is in the form of a biconvex tablet, each convex side of the tablet has a face, each face has at least two openings, bored through the coating to expose a portion of the core surface to the medium of use.

18. The drug delivery device according to claim 17, further characterized in that the openings are drilled only on one side.

19. The drug spraying device according to claim 18, further characterized in that approximately 10 to approximately 60 openings are drilled in one face.

20. - A method for the preparation of the device according to claim 1, for the controlled release of an active agent, wherein: a) the layers of the core are prepared separately by dry mixing or wet granulating the polymer which by hydration produces globules microscopic gelatinous and granulating excipients, and dry-mix or wet-granulate the pharmaceutically active ingredient with the polymer which by hydration produces microscopic gelatinous globules and the necessary excipients; b) compress the mixtures to form the cores in appropriate layers; c) applying the coating by dipping the entire core, or by spray coating the entire core with a suspension of the coating material; and d) drilling openings through the coating to expose the desired core surface area.

21. The method according to claim 20, further characterized in that the pharmaceutically active ingredient is nifedipine.

22. The method according to claim 20, further characterized in that the pharmaceutically active ingredient is lovastatin.

23. The method according to claim 20, further characterized in that the pharmaceutically active ingredient is simvastatin.