The present invention relates to a continuous process for purifying a chain-extended aliphatic polyester constructed from aliphatic dicarboxylic acids and aliphatic diols in a degassing apparatus, wherein the crude polyester is degassed for 3 to 30 minutes at a pressure of 0.01 to 5 mbar in the presence of 1% to 7% by weight, based on the total weight of the crude polyester, of an entraining agent.

Method for obtaining biodegradable polymers that has a stage of esterification and/or transesterification and amidation reaction, a stage of prepolycondensation, a stage of polycondensation, a stage of extraction and a stage of drying, eliminating the use of chain extenders. The polymer can achieve all the range of viscosities desired and with an improved colour compared to the polymer from other methods, where chain extenders are used, provide a more efficient process, that is environmentally cleaner and safer for the operatives.

Provided herein is a bioresorbable polyester wherein the metal content of the polyester is >0 ppm and <40 ppm, a controlled release pharmaceutical composition containing such polyesters, and a kit for injecting a controlled release pharmaceutical composition. Also provided herein is a method of purifying a bioresorbable polyester with a metal content >0 ppm comprising the steps of: i) dissolving the polyester in an organic solvent to form a polyester-solvent solution, wherein the organic solvent comprises at least one heteroatom selected from oxygen, nitrogen, sulphur and phosphorus; ii) precipitating the polyester from the polyester-solvent solution by combining the polyester-solvent solution with an organic non-solvent, said non-solvent being an alcohol; and (iii) separating the precipitated polyester from the solvent and non-solvent to obtain a purified polyester.

Provided herein is a bioresorbable polyester wherein the metal content of the polyester is >0 ppm and <40 ppm, a controlled release pharmaceutical composition containing such polyesters, and a kit for injecting a controlled release pharmaceutical composition. Also provided herein is a method of purifying a bioresorbable polyester with a metal content >0 ppm comprising the steps of: i) dissolving the polyester in an organic solvent to form a polyester-solvent solution, wherein the organic solvent comprises at least one heteroatom selected from oxygen, nitrogen, sulphur and phosphorus; ii) precipitating the polyester from the polyester-solvent solution by combining the polyester-solvent solution with an organic non-solvent, said non-solvent being an alcohol; and (iii) separating the precipitated polyester from the solvent and non-solvent to obtain a purified polyester.

Provided is a process for the removal of tetrahydrofuran from polyesters or copolyesters comprising 1,4-butylene dicarboxylate repeating units and from compositions comprising the polyesters or copolyesters.

Provided is a process for the removal of tetrahydrofuran from polyesters or copolyesters comprising 1,4-butylene dicarboxylate repeating units and from compositions comprising the polyesters or copolyesters.

The present invention is directed to an improved purification process using additive and activated carbon for purifying resorbable polymers suitable for industrial manufacturing. The metal catalyst concentration in the purified resorbable polymers of this invention is preferably less than 1 ppm. The method can be used to obtain high molecular weight polymers that are substantially metal free.

The present invention is directed to an improved purification process using additive and activated carbon for purifying resorbable polymers suitable for industrial manufacturing. The metal catalyst concentration in the purified resorbable polymers of this invention is preferably less than 1 ppm. The method can be used to obtain high molecular weight polymers that are substantially metal free.

The present invention relates to a method for preparing a polyetherester copolymer having excellent economical efficiency by recycling unreacted diol and excellent physical properties. Accordingly, the preparation method may prepare a polyetherester copolymer of high purity having excellent economical efficiency by purifying a byproduct to separate a recycle stream including unreacted diol therefrom, and reusing the recycle stream.

The present invention relates to a method for preparing a polyetherester copolymer having excellent economical efficiency by recycling unreacted diol and excellent physical properties. Accordingly, the preparation method may prepare a polyetherester copolymer of high purity having excellent economical efficiency by purifying a byproduct to separate a recycle stream including unreacted diol therefrom, and reusing the recycle stream.