Agrawal C M, Pennick A, Wang X, Schenck R C
Department of Orthopaedics, University of Texas Health Science Center at San Antonio 78284-7774, USA.
J Biomed Mater Res. 1997 Sep 15;36(4):516-21. doi: 10.1002/(sici)1097-4636(19970915)36:4<516::aid-jbm9>3.0.co;2-h.
Tissue ingrowth into porous-coated orthopedic and dental implants is commonly used as a means to achieve long-term fixation of these prostheses. However, the degree of tissue ingrowth is often inadequate and inconsistent. If the pores of these implants are impregnated with a controlled drug release system delivering relevant growth factors, then it might be possible to stimulate more tissue ingrowth. The present study introduces such a system based on biodegradable polymers and investigates its protein release profile and polymer degradation characteristics. Porous coated titanium implants were impregnated with a mixture of a 50%-50% polylactic acid-polyglycolic acid copolymer and a model protein, soybean trypsin inhibitor. Control implants contained only the polymer and no protein. The implants were subjected to hydrolytic degradation in phosphate buffered saline at 37 degrees C for periods of 3, 6, and 11 weeks. The protein release and the mass and molecular weight of the polymer were monitored. The results indicate that the protein is released in three distinct phases and the polymer loses almost all its mass and molecular weight by 11 weeks. There was a significant difference in the polymer degradation characteristics between the control and test implants, which might be the result of some complex polymer-protein interactions.
组织长入多孔涂层的骨科和牙科植入物中通常被用作实现这些假体长期固定的一种手段。然而，组织长入的程度往往不足且不一致。如果这些植入物的孔隙中浸渍有递送相关生长因子的可控药物释放系统，那么有可能刺激更多的组织长入。本研究引入了一种基于可生物降解聚合物的系统，并研究了其蛋白质释放曲线和聚合物降解特性。将多孔涂层钛植入物用50%-50%的聚乳酸-聚乙醇酸共聚物与一种模型蛋白大豆胰蛋白酶抑制剂的混合物进行浸渍。对照植入物仅含有聚合物而不含蛋白质。将植入物在37℃的磷酸盐缓冲盐水中进行水解降解3、6和11周。监测蛋白质释放以及聚合物的质量和分子量。结果表明蛋白质以三个不同阶段释放，并且聚合物在11周时几乎失去了所有的质量和分子量。对照植入物和测试植入物之间的聚合物降解特性存在显著差异，这可能是一些复杂的聚合物-蛋白质相互作用的结果。
