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Patent US4442051A successfully refreshed from Google Patents.
US4442051A
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US
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Encapsulation of indomethacin
Assignee: Nicholas Pty Ltd
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Filing: 1981-04-15
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Granted: 1984-04-10
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Expires: 2001-04-15
Abstract
Abstract Indomethacin is encapsulated by aqueous gelatin/polysaccharide coacervation by first forming a dispersion or paste of Indomethacin in a water-miscible liquid polyhydroxyalkane. Preferably the coacervate system is gelatin/acacia and the polyhydroxyalkane is glycerol.
Inventors
- 👤 James S. Rowe
- 👤 John E. Carless
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:29
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/48; A61K9/50; A61K9/5089; A61K31/00; A61K31/33; A61K31/395; A61K31/40; A61K31/403; A61K31/404; A61K31/405; A61K9/5005; A61K9/5021; A61K9/5052; A61K9/5057; G; G03; G03C; G03C1/00; G03C1/005; G03C1/04; G03C1/047; G03C2001/0471; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2984; Y10T428/2989
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
52 words
A method of encapsulating Indomethacin comprising mixing Indomethacin with a water-miscible liquid polyhydroxyalkane to form a dispersion or paste, dispersing said dispersion or paste in an aqueous solution of a gelatin/polysaccharide coacervate system, causing coacervation of said system to encapsulate Indomethacin with a coacervate complex, and hardening and dehydrating the resultant microcapsules.
Claim 2
Independent Claim
52 words
A method of encapsulating Indomethacin comprising mixing Indomethacin with a water-miscible liquid polyhydroxyalkane to form a dispersion or paste, dispersing said dispersion or paste in an aqueous solution of a gelatin/polysaccharide coacervate system, causing coacervation of said system to encapsulate Indomethacin with a coacervate complex, and hardening and dehydrating the resultant microcapsules.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1 wherein the polysaccharide is acacia, and the gelatin is an acid-processed pig skin gelatin having an isoelectric point of 8.5-9.5.
Claim 4
Dependent Claim
36 words
A method as claimed in claim 1 wherein the Indomethacin has a 50% weight median particle diameter in the range 5 to 10 microns with less than 5% w/w of particles greater than 33 microns diameter.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 1 wherein Indomethacin is present in an amount in the range 15 to 20% by weight of the combined dry weight of the coacervate system and Indomethacin.
Claim 6
Dependent Claim
30 words
A method as claimed in claim 1 wherein the polyhydroxyalkane is a C 3 -C 6 straight chain alkane with one hydroxy group on each carbon atom of the chain.
Claim 7
Dependent Claim
12 words
A method as claimed in claim 1 wherein the polyhydroxyalkane is glycerol.
Claim 8
Dependent Claim
37 words
A method as claimed in claim 1 wherein the gelatin and polysaccharide are used as 1-3% w/v solutions, and the coacervation is carried out at 41°-46° C., and at a pH in the range 3.8 to 4.0.
Claim 9
Dependent Claim
24 words
A method as claimed in claim 7 wherein said solutions are 3% w/v, the temperature is 46° C. and the pH is about 3.9.
Claim 10
Dependent Claim
19 words
A method as claimed in claim 1 wherein the coacervate coating is hardened by treatment with aqueous formaldehyde solution.
Claim 11
Dependent Claim
24 words
A method as claimed in claim 1 wherein the amount of polyhydroxyalkane used constitutes 2 to 20% by weight of the aqueous coacervation suspension.
Claim 12
Dependent Claim
27 words
A method as claimed in claim 1 wherein the dehydration is carried out by suspending the microcapsules in a dehydrating agent and subsequently drying the dehydrated microcapsules.
Claim 13
Dependent Claim
13 words
A method as claimed in claim 11 wherein the dehydrating agent is isopropanol.
Claim 14
Independent Claim
164 words
A method of preparing a free flowing particulate Indomethacin product wherein particulate Indomethacin having a 50% weight median particle diameter in the range 5 to 10 microns with less than 5% w/w of particles greater than 33 microns diameter is mixed with glycerol to form a dispersion or paste; said dispersion or paste is dispersed in a 41° to 46° C., 1-3% w/v aqueous solution of acacia or acid-processed pig skin gelatin having an isoelectric point of 8.5-9.5; the resultant dispersion is stirred into a 41° to 46° C., 1-3% w/v aqueous solution of said gelatin or acacia respectively; the pH is adjusted to pH 3.8 to 4.0 to cause coacervation to encapsulate the Indomethacin in a gelatin/acacia coacervate complex; the said complex coating is hardened by addition of formaldehyde, rapidly cooling the mixture to below 10° C., maintaining a temperature below 10° C. whilst washing the resultant microcapsules with water and subsequently dehydrating them by suspending in isopropanol, and drying the dehydrated microcapsules.
Claim 15
Independent Claim
164 words
A method of preparing a free flowing particulate Indomethacin product wherein particulate Indomethacin having a 50% weight median particle diameter in the range 5 to 10 microns with less than 5% w/w of particles greater than 33 microns diameter is mixed with glycerol to form a dispersion or paste; said dispersion or paste is dispersed in a 41° to 46° C., 1-3% w/v aqueous solution of acacia or acid-processed pig skin gelatin having an isoelectric point of 8.5-9.5; the resultant dispersion is stirred into a 41° to 46° C., 1-3% w/v aqueous solution of said gelatin or acacia respectively; the pH is adjusted to pH 3.8 to 4.0 to cause coacervation to encapsulate the Indomethacin in a gelatin/acacia coacervate complex; the said complex coating is hardened by addition of formaldehyde, rapidly cooling the mixture to below 10° C., maintaining a temperature below 10° C. whilst washing the resultant microcapsules with water and subsequently dehydrating them by suspending in isopropanol, and drying the dehydrated microcapsules.
Claim 16
Dependent Claim
26 words
A method as claimed in claim 13 wherein said aqueous solutions are 3% w/v and at 46° C., and the pH is adjusted to about 3.9.
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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) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |