聚右旋乳酸-胸腺五肽立体复合物的药物缓释研究

Poly(D-lacitde)(PDLA) were synthesized by ring opening polymerization of D-lactide using zinc lactate as catalyst. Stereocomplexes of PDLA/TP5 were obtained by mixing solutions of acetonitrile containing PDLA and aqueous solutions of thymopentin (TP5) through stereocomplexation between PDLA and TP5 chains which were proved by FT-IR and DSC. Thymopentin was uesd as a model drug to evaluate the potential of PDLA for forming drug delivery systems with L-con?gured peptides. The in?uence of PDLA molecular weight and the stereocomplex composition on the release behavior were investigated. Release of TP5 performed as zero-order release kinetics. Higher polymer molecuar leads to slower release rate due to more compact structure which disfavors degradation of stereocomplexes and drug diffusion. Drug load exhibits little in?uence on the release pro?le due to the high water solubility of TP5 while too much drug load will lead to a brust release. In all cases, nearly 35% of TP5 is released in 200 hours and there was no sign of an ending of this controlled release behavior at that time.