Controlled release composition comprising a physiologically active substance, hydroxynaphthoic acid and a lactic acid polymer

Disclosed is a controlled release composition comprising (1) a physiologically active substance or salt thereof in an amount of about 14% (w/w) to about 24% (w/w) based on the total composition weight, (2) hydroxynaphthoic acid selected from the group consisting of 3-hydroxy-2-naphthoic acid and 1-hydroxy-2-naphthoic acid or salt thereof, and (3) a lactic acid polymer or salt thereof having a weight-average molecular weight of 15000 to 50000 in which the content of polymers having molecular weights of 5000 or less is about 5% by weight or less, wherein the molar ratio of said hydroxynaphthoic acid or salt thereof to said physiologically active substance or salt thereof is from 3:4 to 4:3. The composition is used for medicaments for the treatment of prostatic cancer, prostatic hyperplasia, endometriosis, uterine myoma, uterine fibroma, precocious puberty, dysmenorrheal or breast cancer, or as a contraceptive agent.