Pitt C G, Marks T A, Schindler A
NIDA Res Monogr. 1981;28:232-53.
The classes of polymer which form the basis of different types of drug delivery systems are discussed, and the relationships between the chemical structure of the polymer and its permeability, morphology, biodegradability, and mechanical properties are considered, using polyesters as specific examples. Studies of the permeability and biodegradability of poly epsilon-caprolactone), poly(DL-lactic acid), and various copolymers are described and used to illustrate how these properties may be varied by the choice of polymer structure. An induction period prior to bioerosion of these polymers, coupled with high permeability, permits their use as reservoir devices (capsules) which exhibit constant, diffusion-controlled drug release rates and which erode after the drug is exhausted. The applications of this approach to the long term delivery (1 year) of levonorgestrel, a contraceptive agent, and the short term delivery (1-2 months) of naltrexone, a narcotic antagonist, are described.
讨论了构成不同类型药物递送系统基础的聚合物类别，并以聚酯为例，考虑了聚合物的化学结构与其渗透性、形态、生物降解性和机械性能之间的关系。描述了聚ε-己内酯、聚（DL-乳酸）和各种共聚物的渗透性和生物降解性研究，并用于说明如何通过聚合物结构的选择来改变这些性能。这些聚合物在生物侵蚀之前的诱导期，加上高渗透性，使其能够用作储库装置（胶囊），表现出恒定的、扩散控制的药物释放速率，并且在药物耗尽后会发生侵蚀。描述了这种方法在长效递送（1年）避孕药左炔诺孕酮和短效递送（1-2个月）麻醉拮抗剂纳曲酮方面的应用。
