Virto Maria Rosa, Elorza Begoña, Torrado Susana, Elorza Maria de Los Angeles, Frutos Gloria
Department of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Complutense University, Madrid 28040, Spain.
Biomaterials. 2007 Feb;28(5):877-85. doi: 10.1016/j.biomaterials.2006.09.045. Epub 2006 Oct 24.
Poly(D,L-lactide-co-glycolide) (PLGA) biodegradable microspheres with gentamicin for local treatment of microbial bone infection were prepared and characterized. Gentamicin was assayed spectrophotometrically at 332 nm after derivation with the o-phthalaldehyde; biodegradable polymers studied did not interfere with this method of gentamicin analysis. PLGA microspheres were made by the double emulsion solvent evaporation method with modifications. The first W(1)/O emulsion was obtained by ultrasonication or high-speed homogenization, and a large aqueous phase W(2) (200 ml) was used. The ultrasonication method increases the microsphere percentage observed in the 20-40 microm size range and, in all cases SEM-microphotographs revealed homogeneous and spherically shaped particles with smooth surfaces. The method including ultrasonication proposed in the present work improved the encapsulation efficiency of gentamicin by nearly 100% (97.94%). Several mathematical models based on heterogeneous hydrolytic degradation were applied to evaluate their suitability in describing gentamicin released from PLGA microspheres. Two models, one of them including an autocatalytic process, were finally proposed to contribute to understand the mass transport mechanism involved in drug release from these microspheres.
制备并表征了载有庆大霉素的聚（D，L-丙交酯-共-乙交酯）（PLGA）可生物降解微球，用于局部治疗微生物性骨感染。用邻苯二甲醛衍生后，在332nm处用分光光度法测定庆大霉素；所研究的可生物降解聚合物不干扰这种庆大霉素分析方法。PLGA微球采用双乳液溶剂蒸发法并加以改进制备。通过超声处理或高速均质化获得第一W(1)/O乳液，并使用大量水相W(2)（200ml）。超声处理方法增加了在20-40微米尺寸范围内观察到的微球百分比，并且在所有情况下，扫描电子显微镜照片显示颗粒均匀且呈球形，表面光滑。本工作中提出的包括超声处理的方法将庆大霉素的包封效率提高了近100%（97.94%）。应用了几种基于非均相水解降解的数学模型来评估它们在描述从PLGA微球中释放的庆大霉素方面的适用性。最终提出了两个模型，其中一个包括自催化过程，以有助于理解这些微球中药物释放所涉及的传质机制。
