近年来,长效制剂有较大发展。长效制剂的制法有很多,其中之一是用合成聚合物作为主要成分。最早是采用不能降解的聚合物,但在许多应用场合下,以采用生物降解聚合物更好。最有希望的药物-聚合物组成物是植入剂、注射剂,可控制地缓慢释放药物几周或数月。可生物降解的避孕药注射剂或植入剂应恒速释放一年(甾体药物)。有关可生物降解的药物释放系统的报道正迅速增长。生物吸收(Bioabsorbable)、生物蚀解(Bioerodible)及生物降解(Biodegrada-ble)等名词也常交替使用。在生物蚀解系统聚合物的侧基被水解或离解从而使装置系统缓慢蚀解,不过聚合物的骨架没有降解。生物降解作用和可生物降解聚合物 In recent years, long-acting preparations have made great progress. There are many ways to make long-acting preparations, one of which is the use of synthetic polymers as the main ingredient. The earliest use of non-degradable polymers, but in many applications, the use of biodegradable polymers is better. The most promising drug-polymer compositions are implants, injections, and controlled release of the drug for weeks or months. Biodegradable contraceptives Injections or implants should be released at a constant rate for one year (steroid). Reports of biodegradable drug delivery systems are rapidly growing. Bioabsorbable, bioerodible and biodegrada-ble are also often used interchangeably. The pendant groups in the polymer are degraded or dissociated by the bioerod system, leaving the device system slowly eroding, though the polymer framework is not degraded. Biodegradation and biodegradable polymers