Sharifpoor Soroor, Amsden Brian
Department of Chemical Engineering, Queen's University, Kingston, Canada.
Eur J Pharm Biopharm. 2007 Mar;65(3):336-45. doi: 10.1016/j.ejpb.2006.09.008. Epub 2006 Sep 28.
Low-molecular-weight poly(epsilon-caprolactone-co-1,3-trimethylene carbonate) and poly(1,3-trimethylene carbonate) are potential vehicles for the regio-specific delivery of water-soluble agents. In this paper, the characteristics and the mechanism governing the in vitro release of a model water-soluble drug, vitamin B12, from these polymer vehicles were determined. The loading of vitamin B12 was kept to 1 w/w%. The oligomers examined ranged from amorphous, high viscosity to crystalline but low viscosity. The oligomers did not degrade appreciably in vitro. The total fraction of vitamin B12 released increased as the crystallinity of the oligomers decreased, reaching nearly total release only for the completely amorphous oligomers. The rate of release was fastest for the amorphous oligomers and dependent on their viscosity. Inclusion of a more osmotically active agent, trehalose, into the vitamin B12 particles through co-lyophilization resulted in enhanced total fraction released and a faster release rate. The results are consistent with an osmotically driven release mechanism.
低分子量聚（ε-己内酯-共-1,3-三亚甲基碳酸酯）和聚（1,3-三亚甲基碳酸酯）是用于区域特异性递送水溶性药物的潜在载体。本文测定了一种模型水溶性药物维生素B12从这些聚合物载体中体外释放的特征和控制机制。维生素B12的负载量保持在1 w/w%。所研究的低聚物范围从无定形、高粘度到结晶但低粘度。这些低聚物在体外没有明显降解。随着低聚物结晶度的降低，维生素B12释放的总分数增加，仅对于完全无定形的低聚物才达到几乎完全释放。无定形低聚物的释放速率最快，并且取决于它们的粘度。通过共冻干将一种渗透活性更高的试剂海藻糖包含到维生素B12颗粒中，导致释放的总分数增加且释放速率更快。结果与渗透驱动释放机制一致。
