含十八甲基醋酸炔诺酮肟微球的制备及体外释药初探

以Ａ１／Ｚｎ双金属烷氧化物催化剂进行“活”性聚合，制得Ｌ－丙交酯（Ｌ－ＬＡ）与ＤＬ－丙交酯（ＤＬ－ＬＡ）的嵌段共聚物，进而以该聚合物为基材，采用溶剂挥发法制备了含十八甲基醋酸炔诺酮肟（ＮＧＭ）的药物微球。体外释放试验表明，调节共聚物组成及分子量大小，可以改变释药行为并得到零级释放。对共聚物的ＤＳＣ及Ｘ－射线衍射分析进一步揭示了共聚物结构与药物释放的关系。

Block copolymer of DL-and L-lactide/norgestimate microspheres:a new long-acting injectable biodegratable contraceptive

Sequential diblock copolymers composed of L-and DL-lactide, P(L-LA-B-DL-LA), were synthesized through a living ring-opening polymerization initiated by A1/Zn bimetallic alkoxidecomplex[(RO)4Al2O2Zn].Microspheres made with the block copolymers containing 20%wtnorgestimate (NGM)were prepared by a modified solvent-evaporation process. The effects of changingboth the composition and molecular weight of copolymers on the release rate of NGM were determinedin vitro.It was observed that the release profiles varied with the composition and molecular weight ofcopolymers.It is interesting to note that the release rate was greatly increased when the ratio of DL-LAto L-LA was 50/50 and the zero-order release could be obtained while L-LA segment in the blockcopolymer was 75%. The block copolymers were subjected to measurements of wide-angle X-ray diffraction anddifferential scanning calorimetry(DSC)analysis and the results revealed that the morphology of blockcopolymers was different from that of both homopolymers. which affected the release of drug and degra-dation of polymer.