CONTROLLED RELEASE COMPOSITION AND METHOD OF PRODUCING THE SAMEABSTRACTA controlled release composition containing aphysiologically active substance in high content, suppressing the initial excess release, and achieving astable release speed over a long period of time is provided. 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 thetotal 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 thecontent 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.No suitable figure
