Takeda Chemical Industries, Inc.

Wako Pure Chemical Industries, Inc.

Kayoko Okamoto

Yasutaka Igari

Shigeru Kamei

Atsunori Sano

Yutaka Yamagata

Akira Saikawa

Masahisa Oka

Masafumi Misaki

Kazumichi Yamamoto

This invention provides a sustained-release preparation comprising a biodegradable polymer metal salt and broactive polypeptide, with enhanced entrapment of the bioactive polypeptides, a suppression of initial burst, and a constant long-term release of the bioactive polypeptides.

Method of producing sustained-release preparation

The present invention relates to a matrix for sustained-release preparation comprising an ester formed at a terminal carboxyl group of a straight-chain polyester which essentially consists of an .alpha.-hydroxymonocarboxylic acid. The matrix is stable to light, heat, moisture, coloring etc., and is of low toxicity. The sustained-release preparation produced by using the ester of the present invention offers stable drug release over an extended period of time, ensuring sustained stable effect. Furthermore, the sustained-release preparation does not show excess drug release just after administration.

Matrix for 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.

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Osaka, Japan

Kayoko Okamoto