Production of sustained-release preparation for injection

Abstract

Disclosed is a method of producing a sustained-release preparation for injection, which comprises adding to microspheres which are obtained from w/o emulsion with a solution containing a physiologically active peptide as an internal aqueous phase and a solution containing a polylactic acid having a weight-average molecular weight of about 5,000 to about 25,000 as an oil phase, a sugar in an amount of about 2 to about 60% (w/w) relative to the microspheres; freeze drying and subsequent heating at the temperature ranging from the glass transition temperature of the microspheres to the temperature which is higher by about 20° C. than the glass transition temperature for about 24 to about 120 hours; and the method of the present invention suppresses microsphere particle aggregation during production process, makes it possible to almost perfectly remove the water and organic solvent in microspheres, and yields microspheres having good dispersibility and storage-stability.

Dependencies are inferred from the claim text.