Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Tablets – lozenges – or pills
Reexamination Certificate
1999-06-04
2003-10-14
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Tablets, lozenges, or pills
C424S465000, C424S468000, C424S471000, C424S473000, C424S474000, C424S479000, C424S482000, C424S484000, C424S489000
Reexamination Certificate
active
06632451
ABSTRACT:
FIELD OF THE INVENTION
The invention is in the field of drug delivery. Specifically, the invention is directed to a drug delivery system that provides enterally-administered pharmaceuticals in a two pulse fashion.
BACKGROUND OF THE INVENTION
The ability to deliver a drug in a manner that targets the drug for absorption at a specific region of the gastrointestinal tract is desirable for many reasons. Such a delivery system would allow the medical practitioner to locally treat gastrointestinal diseases. Local treatment of gastrointestinal diseases would avoid systemic side effects of drugs or inconvenient and painful direct delivery of drugs. In addition, such a delivery system could potentially increase the efficiency of a drug, thus allowing a reduction of the minimum effective dose of the drug. A delivery system that could target a drug to a specific region of the gastrointestinal tract would thus be useful for the treatment of a wide variety of diseases and conditions.
WO 97/25979 describes a drug-delivery device for the targeting of various parts of the gastrointestinal tract. A core containing a drug is coated with a hydrophobic polymer which contains hydrophilic, non-water-soluble particles embedded therein. These particles serve as channels for aqueous medium entering the core and for the release of drugs by diffusion through these channels. This delivery system can target various parts of the gastrointestinal tract and slowly release its drug load.
U.S. Pat. No. 5,525,634 describes a delivery device that contains a drug in combination with a matrix. The matrix contains a saccharide-containing polymer. The matrix-drug combination can be coated or uncoated. The polymer is resistant to chemical and enzymatic degradation in the stomach and susceptible to enzymatic degradation in the colon by colonic bacteria.
EP 485,840 (Röhm GmbH), discloses a gastrointestinal delivery device containing, as a coating, a mixture of a polysaccharide and Eudragit®™. However, this formulation does not allow control of the rate of liquid entry into the formulation. Therefore, control of the site of release of the drug cannot be achieved. Further, the polysaccharide is not provided in particulate form.
U.S. Pat. No. 4,627,850 (Deters et al.) discloses an osmotic capsule for the controlled rate delivery of a drug comprising outer and inner walls each formed of a different polymeric material, the inner wall defining a space containing the drug, with a passageway through the walls connecting the exterior of the outer wall with the interior of the inner wall.
U.S. Pat. No. 4,904,474 (Theuwes et al.) discloses a colonic drug delivery device comprising means for delaying the delivery in the drug and in the small intestine and means for delivering the drug in the colon. This device comprises osmotic means for forcing the active pharmaceutical agent out from the compartment in which it is contained through an exit provided in said compartment, into the colon. The means for delaying delivery in the stomach or in the small intestine are pH-resistant coatings. The delay in delivery of the drug is time-based.
U.S. Pat. No. 5,593,697 describes a pharmaceutical implant containing a biologically active material, an excipient comprised of at least one water soluble material and at least one water insoluble material, and a polymer film coating adapted to rupture at a predetermined period of time after implantation.
U.S. Pat. No. 4,252,786 describes a controlled release tablet for the administration of medicinal agents over a prolonged period of time.
U.S. Pat. Nos. 5,260,069 and 5,472,708 describe a dosage form for delivering drugs, and particularly drugs that cannot be released by diffusion through a porous coating, such as water insoluble drugs.
U.S. Pat. No. 4,897,270 describes a pharmaceutical tablet comprising a tablet core and a film coat to mask the taste of the core. The core disintegrates immediately following rupture of the film coat.
U.S. Pat. No. 5,204,121 describes a drug release system in pellet form where the pellets consist of a core containing the active compound. The core is surrounded by a polymer-containing jacket and a undigestible lacquer layer that is permeable to water. The outer lacquer layer does not dissolve but is said to carry water to the migration controlling jacket layer which then brings the liquid in contact with the drug containing core.
U.S. Pat. No. 4,891,223 describes compositions for the sustained release of a pharmaceutical, comprising a drug-containing core, a first coating containing a polymer swellable upon penetration of the surrounding media, and a second coating, enveloping the first coating, comprising a polymer that is water-soluble and that forms a semi-permeable barrier. The outer coating is said to permit diffusion of the media, into the first coating and then diffusion of the dissolved drug into the surrounding media. The second coating must have requisite stretchability to prevent rupture of a second coating due the swelling of the first coating until a specific time in the release pattern.
U.S. Pat. No. 4,327,725 describes a variation of a basic osmotic device for drug release. The structure of the device is an active agent enclosed in a hydrogel layer that is enclosed in a semi-permeable membrane. The semi-permeable membrane allows diffusion of external fluid but does not allow diffusion of the solution of active agent to the surrounding environment. The hydrogel swells with absorption of external fluid and exerts pressure on the solution of active agent in the external fluid. The solution of the active agent in the external fluid is then delivered to the surrounding media through a single specially constructed passageway through the hydrogel layer and the membrane.
Some pulsatile delivery systems exist in the art. U.S. Pat. No. 5,162,117 describes a two pulse tablet of flutamide for the treatment of prostate cancer. The first pulse is contained in an immediate release layer while the second pulse is obtained from a core which contains a solid dispersion of the flutamide in a carrier. The pulses are separated by a film layer of an enteric coating at 4-15% weight percent of the core. The enteric coating slowly dissolves after the delivery of the first pulse of drug allowing the release of the second pulse. Enteric coatings as a delaying layer suffer from disadvantages of lack of parameters to control the precise timing of the delivery of the second pulse and are limited to delivering the second pulse to the small intestine. The slightly acidic environment of the human colon can cause the enteric coating to stop dissolving upon colon entry and may cause the second dose to be undelivered if the delay time between the pulses is longer than the time of transit through the small intestine. This disadvantage would be magnified if the first dose were to be limited to delivery to the small intestine and not to the stomach in which case the delay to the second pulse would be limited to about 3-4 hours.
U.S. Pat. No. 5,260,069 describes a capsule which contains a plurality of pellets with varying delay times to drug release. By mixing pellets of different delay times one can obtain pulsatile delivery of the drug. The delay time to drug delivery of the pellets is controlled by the pellets containing a swelling agent and the drug and being surrounded by a membrane that contains a water insoluble film and a water soluble film. The water soluble component of the film dissolves slowly thereby weakening the membrane. Water entry into the pellets causes them to swell and burst the weakened membrane. U.S. Pat. No. 5,260,068 describes a unit dosage form that contains populations of pellets or particles that have different delay times to drug delivery. The drug is contained in the pellet along with an osmotic agent. The pellets are coated with a water permeable, water-insoluble film that allows water diffusion into the pellet. The osmotic agent dissolves in the water causing the pellet to swell and eventually burst to release drug. Differences in the water permeability of the f
Flashner Moshe
Lerner E. Itzhak
Penhasi Adel
Channavajjala Lakshmi S.
Dexcel Pharma Technologies Ltd.
Graeser D'vorah
Page Thurman K.
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