Sustained-release preparation capable of releasing a physiologically active substance
AssigneeTakeda Chemical Industries, Ltd.
InventorsHiroaki Okada, Yayoi Douken
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Abstract
Disclosed is a sustained-release preparation comprising 1) a polymer of lactic acid having a weight-average molecular weight of about 25,000 to about 60,000 and 2) a physiologically active substance, and which releases the physiologically active substance over a period of at least about 5 months; the sustained-release preparation shows an almost continuous zero order release of the physiologically active substance over a period of as long as about 5 months.
Claims16
A sustained-release preparation, comprising a plurality of microcapsules, said microcapsules comprising a physiologically active substance and a hydrolyzed polymer of lactic acid, said hydrolyzed polymer of lactic acid being produced by subjecting a plurality of cyclic dimers of lactic acid to a ring-opening reaction, polymerizing said cyclic dimers of lactic acid in the presence of a catalyst to form a lactic acid polymer, hydrolysing said polymer, and refining said hydrolyzed polymer, wherein said preparation provides a release of the physiologically active substance over a period of at least about 5 months.
A method of producing a sustained-release preparation releasing a physiologically active substance over a period of at least about 5 months, which comprises subjecting to microencapsulation a water-in-oil emulsion with a solution containing a physiologically active substance as an internal aqueous phase and with a solution containing a polymer of lactic acid having a weight-average molecular weight of about 25,000 to about 60,000 as an oil phase.
Dependencies are inferred from the claim text.