EP0388954A2
Expired / Lapsed
EP
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Freeze-dried polymer dispersions and the use thereof in preparing sustained-release pharmaceutical compositions
Assignee: FMC Corp
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Filing: 1990-03-22
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Granted: —
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Expires: 2010-03-22
Abstract
Abstract Freeze-dried polymer latices, which can be reconstituted in water to give aqueous polymer dispersions having high polymer solids content, are described. The reconstituted polymer dispersions are useful in preparing sustained-release drug formulations, particularly of water-soluble drugs, by the wet granulation method without over wetting.
Inventors
- 👤 Dev K. Mehra
- 👤 Chimanal I. Patel
- 👤 Clayton I. Bridges
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 01:14
CPC Classifications
A; A61; A61K; A61K9/00; A61K9/14; A61K9/16; A61K9/1605; A61K9/1629; A61K9/1635; A61K9/1652
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
49 words
A freeze-dried aqueous polymer pseudolatex capable of being reconstituted in water to provide an aqueous polymer dispersion characterized in that the polymer content can be varied over wide limits, the initial aqueous pseudolatex being formed at a polymer level below that at which high viscosities and/or emulsion instability occurs.
Claim 2
Dependent Claim
49 words
A freeze-dried aqueous polymer pseudolatex capable of being reconstituted in water to provide an aqueous polymer dispersion characterized in that the polymer content can be varied over wide limits, the initial aqueous pseudolatex being formed at a polymer level below that at which high viscosities and/or emulsion instability occurs.
Claim 3
Dependent Claim
37 words
The composition of claim 1 characterized in that the pseudolatex contains at least one water-insoluble polymer selected from the class consisting of ethylcellulose, polyvinyl acetate phthalate, cellulose acetate phthalate, cellulose acetate, cellulose acetate butyrate and polyvinyl acetate.
Claim 4
Dependent Claim
13 words
The composition of claim 2 characterized in that the water-insoluble polymer is ethylcellulose.
Claim 5
Dependent Claim
37 words
The freeze-dried aqueous polymer of claim 1 formed from an initial aqueous pseudolatex characterized by a dispersion of ethylcellulose in an aqueous solution of a water-soluble polymer selected from the class consisting of hydroxypropylmethyl cellulose and polyvinylpyrrolidone.
Claim 6
Dependent Claim
21 words
The composition of claim 3 characterized in that the ratio of ethylcellulose to water-soluble polymer is 10 to 1 by weight.
Claim 7
Dependent Claim
14 words
The composition of claim 4 characterized in that the water-soluble polymer is hydroxypropylmethyl cellulose.
Claim 8
Dependent Claim
32 words
The composition of claim 5 characterized in that triethyl citrate is added as a plasticizer, the triethyl citrate being present at a 24% weight weight concentration based on the weight of ethylcellulose.
Claim 9
Dependent Claim
32 words
An aqueous polymer dispersion, suitable for preparing drug formulations by the wet granulation method characterized by (a) the reconstituted aqueous polymer dispersion of claim 1, and (b) a plasticizer for said polymer.
Claim 10
Dependent Claim
46 words
An aqueous polymer dispersion, suitable for preparing drug formulations by the wet granulation method characterized by (a) a reconstituted aqueous polymer dispersion of claim 1 containing above 30% to 70% ethylcellulose as the polymer component, and (b) as a plasticizer for said polymer an acetylated monoglyceride.
Claim 11
Dependent Claim
13 words
The composition of claim 9 characterized in that the plasticizer is triethyl citrate.
Claim 12
Dependent Claim
13 words
The composition of claim 9 characterized in that the plasticizer is dibutyl sebacate.
Claim 13
Independent Claim
81 words
A method of preparing an aqueous polymer dispersion in which the polymer concentration can be varied over wide limits characterized by the steps of: 1. forming an aqueous polymer pseudolatex by dissolving a polymer in a water-immiscible solvent; emulsifying the polymer solvent solution in water at a polymer content below that at which high viscosities are produced and removing the solvent; 2. freeze drying the pseudolatex from 1; and 3. redispersing the freeze-dried pseudolatex in water to the desired polymer content.
Claim 14
Independent Claim
81 words
A method of preparing an aqueous polymer dispersion in which the polymer concentration can be varied over wide limits characterized by the steps of: 1. forming an aqueous polymer pseudolatex by dissolving a polymer in a water-immiscible solvent; emulsifying the polymer solvent solution in water at a polymer content below that at which high viscosities are produced and removing the solvent; 2. freeze drying the pseudolatex from 1; and 3. redispersing the freeze-dried pseudolatex in water to the desired polymer content.
Claim 15
Dependent Claim
12 words
The method of claim 12 characterized in that the polymer is ethylcellulose.
Claim 16
Dependent Claim
33 words
The method of claim 12 characterized in that the polymer is at least one water-insoluble polymer selected from ethylcellulose, polyvinyl acetate, polyvinyl acetate phthalate, cellulose acetate, cellulose acetate phthalate, and cellulose acetate butyrate.
Claim 17
Dependent Claim
112 words
In the method of preparing a pseudolatex by forming a solution of a polymer in a water-immiscible solvent, forming an emulsion of the solvent solution in water and removing the solvent from the emulsion, the improvement of avoiding high viscosity and/or emulsion instability when carrying out the emulsification at high polymer levels, characterized by the steps of: 1. forming a first pseudolatex at a polymer concentration below that at which high viscosity and/or emulsion instability occurs; 2. subjecting the first pseudolatex to freeze drying; 3. recovering the solid freeze-dried pseudolatex from (b), and 4. redispersing the solid freeze-dried pseudolatex from 3. in water to give a pseudolatex of the desired polymer content.
Claim 18
Dependent Claim
112 words
In the method of preparing a pseudolatex by forming a solution of a polymer in a water-immiscible solvent, forming an emulsion of the solvent solution in water and removing the solvent from the emulsion, the improvement of avoiding high viscosity and/or emulsion instability when carrying out the emulsification at high polymer levels, characterized by the steps of: 1. forming a first pseudolatex at a polymer concentration below that at which high viscosity and/or emulsion instability occurs; 2. subjecting the first pseudolatex to freeze drying; 3. recovering the solid freeze-dried pseudolatex from (b), and 4. redispersing the solid freeze-dried pseudolatex from 3. in water to give a pseudolatex of the desired polymer content.
Claim 19
Dependent Claim
12 words
The method of claim 15 characterized in that the polymer is ethylcellulose.
Claim 20
Dependent Claim
39 words
A sustained-release dosage form produced by adding the aqueous polymer dispersion of claim 9 to powdered drug components in the known wet granulation process to form solid granules in which the drug components are distributed in a polymer matrix.
Claim 21
Dependent Claim
33 words
The composition of claim 17 characterized in that the polymer is at least one water-insoluble polymer selected from ethylcellulose, polyvinyl acetate phthalate, cellulose acetate phthalate, cellulose acetate, cellulose acetate butyrate and polyvinyl acetate.
Claim 22
Dependent Claim
12 words
The composition of claim 18 characterized in that the polymer is ethylcellulose.
References Cited (Backward Citations)
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