- Sustained-release preparation
-
A sustained-release preparation comprising a bioactive substance having an acidic group and a biodegradable polymer having an optionally protected basic group which improves the rate of incorporation of the bioactive substance, suppresses its leakage early after administration, and exhibits constantly suppressed release for an extended period of time.
- -
-
-
- Sustained-release preparation
-
A sustained-release preparation which comprises a physiologically active peptide of general formula STR1 wherein X represents an acyl group; R1, R2 and R4 each represents an aromatic cyclic group; R3 represents a D-amino acid residue or a group of the formula STR2 wherein R3 ' is a heterocyclic group; R5 represents a group of the formula --(CH2)n --R5 ' wherein n is 2 or 3, and R5 ' is an amino group which may optionally be substituted, an aromatic cyclic group or an O-glycosyl group; R6 represents a group of the formula --(CH2)n --R6 ' wherein n is 2 or 3, and R6 ' is an amino group which may optionally be substituted; R7 represents a D-amino acid residue or an azaglycyl residue; and Q represents hydrogen or a lower alkyl group, or a salt thereof and a biodegradable polymer having a terminal carboxyl group. The sustained-release preparation shows a constant release of the peptide over a long time and is substantially free from an initial burst.
- -
-
-
- Method of producing sustained-release preparation
-
A method of producing a sustained-release preparation which includes permitting a water-soluble polypeptide to permeate into a biodegradable matrix in the aqueous solution. The production method of the present invention makes possible the permeation of a water-soluble polypeptide into a biodegradable matrix without bringing the water-soluble polypeptide into contact with an organic solvent. Hence the water-soluble polypeptide is prepared without affecting the water-soluble polypeptide bioactivity and is thus effective for use as a pharmaceutical.
- -
-
-
- Method of producing sustained-release microcapsules
-
A method of producing sustained-release microcapsules containing a biologically active substance from an W/O emulsion comprising an inner aqueous phase containing said biologically active substance and an external oil phase containing a biodegradable polymer, characterized in that microcapsules formed on microencapsulation of said biologically active substance with said biodegradable polymer are heated at a temperature not lower than the glass transition temperature of said biodegradable polymer but not so high as to cause aggregation of the microcapsules. This method enables the production of very useful sustained release microcapsules adapted to release a bologically active substance at a calculated rate over a protracted time period starting immediately following administration without an initial burst within one day following administration.
- -
-
-
- Prolonged release preparation and polymers thereof
-
A polymer for a prolonged release preparation which comprises (A) a polylactic acid and (B) a copolymer of glycolic acid and a hydroxycarboxylic acid of general formula STR1 wherein R stands for an alkyl group having 2 to 8 carbons, wherein the weight ratio of (A) and (B) is in the range of 10/90 to 90/10. The drug is released at a constant rate from the preparation over the total release period without a large burst at the initial state. Furthermore, the drug release period of the preparation can be freely controlled by varying the blending ratio of (A) and (B).
- -
-
-
- Biodegradable high-molecular polymers, production and use thereof
-
The invention provides a method of purifying biodegradable aliphatic polyesters which comprises dissolving, in a readily water-soluble organic solvent, a biodegradable aliphatic polyester which contains low-molecular substances and adding water to the resulting solution to thereby remove said low-molecular substances, biodegradable aliphatic polyesters obtained by said method and containing low-molecular substances with a molecular weight of 1,000 or less in an amount of not higher than 3%, and drug-containing compositions which comprise any of said biodegradable polyesters.
- -
-
-
- Polymer, production and use thereof
-
The present invention provides a biodegradable high molecular polymer characterized in that the content of water-soluble low molecular compounds, as calculated on the assumption that said compounds each is a monobasic acid, is less than 0.01 mole per 100 grams of said high molecular polymer. The thus-obtained high molecular polymer has good aging stability and can be used advantageously as an exipient for pharmaceutical preparations.
- -
-
-