Provided is an annular sustained release preparation to be used by opening a center portion thereof, the preparation having a strength enough to avoid cleaving at a welded end portion. More specifically, provided is an annular sustained release preparation comprising at least two polymer tubes having both ends sealed and integrated by pressure-welding or at least one polymer tube and at least one polymer rod having both ends sealed and integrated by pressure-welding and a sex pheromone liquid contained by at least one of the tubes or the tube wherein an annular space can be formed by pulling the tubes or the tube and the rod apart from each other at a center portion therebetween, the central portion not having been pressure-welded and an angle formed between a line connecting respective centers of diameters of the tubes welded to each other or the tube and the rod welded to each other and the pressure application direction is from 0 to 45°.本發明之課題係對於打開中央部位而使用之環狀緩釋性製劑,提供於末端融著部具有不會斷裂的強度之製劑。本發明之解決方式係提供一種環狀緩釋性製劑,其係具備於兩末端經由加壓融著而被密封且一體化之至少2支高分子製細管,或於兩末端經由加壓融著而被密封且一體化之至少1支高分子製細管及至少1支高分子製細棒,並以前述高分子製細管的至少1支收納性費洛蒙液,且藉由將前述未經加壓融著的中央部位相互獨立地拉開,可形成環狀空間之環狀緩釋性製劑,且被融著的前述高分子製細管彼此之間,或被融著的前述高分子製細管與前述高分子製細棒的直徑的中心的連結線與前述加壓方向的夾角角度為0~45°。10...緩釋性製劑11...費洛蒙液12、13...高分子細管15...末端部16...中央部
