US4557925A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Membrane-coated sustained-release tablets and method
Assignee: Gacell Laboratories AB
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Filing: 1984-09-05
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Granted: 1985-12-10
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Expires: 2004-09-05
Abstract
Abstract A sustained-release coated pharmaceutical tablet comprising a drug-containing tablet and a coating or membrane surrounding the same, wherein the coating or membrane is water-insoluble and insoluble in gastrointestinal fluids and consists essentially of a terpolymer of polyvinylchloride, polyvinylacetate, and polyvinylalcohol and a water-soluble pore-creating substance, the said pore-creating substance being randomly distributed in said terpolymer coating, said pore-creating substance being present in amount of one part to 35 parts for each one to ten parts of terpolymer, said coated tablet exhibiting a substantially constant dissolution rate during a major portion of its dissolution time when exposed to gastrointestinal fluids, especially wherein the terpolymer contains 80 to 95% weight per weight of polyvinylchloride, 0.5 to 19% weight per weight of polyvinylacetate, and 0.5 to 10% weight of polyvinylalcohol, and a method for the preparation thereof, are disclosed.
Inventors
- 👤 Ake R. Lindahl
- 👤 Stig A. B. Erlandsson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:14
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/20; A61K9/28; A61K9/2806; A61K9/2813; A61K9/282; A61K9/2826; A61K9/2833; A61K9/284; A61K9/2853
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
128 words
A sustained-release coated pharmaceutical tablet comprising a drug-containing tablet and a coating or membrane surrounding the same, wherein the coating or membrane is water-insoluble and insoluble in gastrointenstinal fluids and consists essentially of a terpolymer of polyvinylchloride, polyvinylacetate, and polyvinylalcohol and a water-soluble pore-creating substance, the said pore-creating substance being randomly distributed in said terpolymer coating, said pore-creating substance being present in amount of one part to 35 parts for each one to ten parts of terpolymer, said coated tablet exhibiting a substantially constant dissolution rate during a major portion of its dissolution time when exposed to gastrointestinal fluids, wherein the terpolymer contains 80 to 95% weight per weight of polyvinylchloride, 0.5 to 19% weight per weight of polyvinylacetate, and 0.5 to 10% weight per weight of polyvinylalcohol.
Claim 2
Dependent Claim
128 words
A sustained-release coated pharmaceutical tablet comprising a drug-containing tablet and a coating or membrane surrounding the same, wherein the coating or membrane is water-insoluble and insoluble in gastrointenstinal fluids and consists essentially of a terpolymer of polyvinylchloride, polyvinylacetate, and polyvinylalcohol and a water-soluble pore-creating substance, the said pore-creating substance being randomly distributed in said terpolymer coating, said pore-creating substance being present in amount of one part to 35 parts for each one to ten parts of terpolymer, said coated tablet exhibiting a substantially constant dissolution rate during a major portion of its dissolution time when exposed to gastrointestinal fluids, wherein the terpolymer contains 80 to 95% weight per weight of polyvinylchloride, 0.5 to 19% weight per weight of polyvinylacetate, and 0.5 to 10% weight per weight of polyvinylalcohol.
Claim 3
Dependent Claim
26 words
The coated tablet of claim 1, wherein the pore-creating substance is a water-soluble substance selected from the group consisting of saccharose, sodium chloride, and potassium chloride.
Claim 4
Dependent Claim
24 words
The coated tablet of claim 1, wherein the pore-creating substance is a water-soluble material selected from the group consisting of polyvinylpyrrolidone and a polyethyleneglycol.
Claim 5
Dependent Claim
21 words
The coated tablet of claim 1, wherein the pore-creating material is also solvent-soluble in solvent employed for coating of the tablet.
Claim 6
Dependent Claim
15 words
The coated tablet of claim 1, wherein a plasticizer is also present in the terpolymer.
Claim 7
Dependent Claim
21 words
The coated tablet of claim 5, wherein the plasticizer is present in a concentration of 0.2 to 4% weight by weight.
Claim 8
Dependent Claim
20 words
The coated tablet of claim 6, wherein the plasticizer is selected from acetyltributylcitrate, polyethyleneglycol, blown castor oil, and glyceryl triacetate.
Claim 9
Dependent Claim
16 words
The coated tablet of claim 5, comprising also a pH-elevating substance in the coating or membrane.
Claim 10
Dependent Claim
13 words
The coated tablet of claim 8, wherein the pH-elevating substance is sodium bicarbonate.
Claim 11
Dependent Claim
29 words
The coated tablet of claim 1, wherein the coating or membrane weighs between 10 mg and 170 mg per tablet, depending upon the size and area of the tablet.
Claim 12
Dependent Claim
26 words
The coated tablet of claim 10, wherein a second coating is present over the terpolymer coating and wherein further drug is present in the second coating.
Claim 13
Dependent Claim
14 words
The coated tablet of claim 11, wherein the second coating is a rapid-release coating.
Claim 14
Dependent Claim
16 words
The coated tablet of claim 12, wherein the said rapid-release coating is a water-based sugar coating.
Claim 15
Dependent Claim
22 words
The coated tablet of claim 13, wherein a seal coating is present between said second water-based sugar coating and the terpolymer coating.
Claim 16
Dependent Claim
21 words
The coated tablet of claim 1, wherein the pore-creating substance has a particle size between about 0.5 millimicron and 50 millimicrons.
Claim 17
Dependent Claim
26 words
The coated tablet of claim 15, wherein the tablet contains a drug selected from the group consisting of potassium chloride, sodium salicylate, choline theophyllinate, and paracetamole.
Claim 18
Dependent Claim
39 words
The coated tablet claim 1, wherein the terpolymer has the approximate molecular formula (PVC)M; (PVAC)N; (PVOH)O; wherein PVC is polyvinylchloride, PVAC is polyvinylacetate, and PVOH is polyvinylalcohol, and wherein M is 31, N is 1 and O is 2.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |