Sinha V R, Khosla L
University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India.
Drug Dev Ind Pharm. 1998 Dec;24(12):1129-38. doi: 10.3109/03639049809108572.
For a long time, subcutaneous implantable drug pellets using nondegradable polymers have been used for long-term, continuous drug administration. The procedure requires surgical implantation and removal of the drug-containing devices or polymeric matrices, which has a significant negative impact on the acceptability of the product candidate. In addition, the release profile from such devices is neither constant nor readily controlled in terms of precision of rate of release and duration of action. These facts have led to the research and development of novel, controllable, nonirritating, noncarcinogenic, biocompatible, and bioabsorbable drug delivery systems for overcoming the drawbacks of nondegradable implantable pellets for prolonged continuous release. Biodegradable implantable systems release the drug over a long period of time with simultaneous or subsequent degradation in the tissue of the polymer to harmless constituents, thus avoiding removal once the therapy is complete. This approach has considerably improved patient acceptability and patient compliance. Various bioabsorbable polymers have been evaluated for controlled implantable drug delivery, including hydrogels, copolymers of polylactic and polyglycolic acids, polylactic acid, poly(orthoesters), polyanhydrides, poly(E-caprolactone), and polyurethanes. Their characteristics have been studied using a variety of drugs, like anticancer agents, hormone agonists and antagonists, nonsteroidal anti-inflammatory agents, neuroleptics, contraceptives, and others. The present paper describes the current research on implantable therapeutic systems, the bioabsorbable polymers, and the biologically active agents being used in this approach.
长期以来，使用不可降解聚合物的皮下植入式药粒一直用于长期、持续给药。该过程需要通过手术植入和取出含药装置或聚合物基质，这对候选产品的可接受性有重大负面影响。此外，此类装置的释放曲线在释放速率的精确性和作用持续时间方面既不恒定也不易控制。这些事实促使人们研发新型、可控、无刺激、无致癌性、生物相容性和生物可吸收的药物递送系统，以克服不可降解植入式药粒在长期持续释放方面的缺点。可生物降解的植入式系统在长时间释放药物的同时，聚合物在组织中同步或随后降解为无害成分，从而在治疗完成后无需取出。这种方法极大地提高了患者的接受度和依从性。人们已对各种生物可吸收聚合物进行了可控植入式药物递送评估，包括水凝胶、聚乳酸和聚乙醇酸共聚物、聚乳酸、聚原酸酯、聚酸酐、聚（ε-己内酯）和聚氨酯。使用多种药物，如抗癌剂、激素激动剂和拮抗剂、非甾体抗炎药、抗精神病药、避孕药等，对它们的特性进行了研究。本文介绍了目前关于植入式治疗系统、生物可吸收聚合物以及在此方法中使用的生物活性剂的研究情况。
