Vivek K, Reddy L Harivardhan, Murthy R S R
Drug Delivery Research Laboratory, Center of Relevance and Excellence in NDDS, Pharmacy Department, Gujarat, India.
Pharm Dev Technol. 2007;12(1):79-88. doi: 10.1080/10837450601168581.
Etoposide-loaded biodegradable microspheres of poly lactic-co-glycolide (PLGA) 50:50, PLGA 75:25, and polycaprolactone (PCL) were prepared by simple o/w emulsification solvent evaparation method and characterized by size analysis and microscopy. The influence of drug to polymer ratio on the entrapment of etoposide was studied. Of all the three types of microspheres, polycaprolactone microspheres (PCL MS) showed the highest entrapment efficiency (94.64%), followed by PLGA 75:25 microspheres (PLGA 75:25 MS) (88.64%) and PLGA 50:50 microspheres (PLGA 50:50 MS) (79.19%). The drug to polymer ratio of 1:20 gave the highest entrapment efficiency for all the three types of microspheres. The in vitro release of etoposide from the three microsphere formulations were studied in phosphate buffer pH 7.4 (pH 7.4 PB) containing 0.1% Tween 80. The microspheres showed an initial burst release, which was highest from the PLGA 50:50 MS and least from the PCL MS. PCL MS microspheres showed the lower and slow drug release than the remaining formulations. The release of etoposide from all the three microsphere formulations followed Higuchi's diffusion pattern. The microspheres in the dissolution medium for 28 days appeared irregular in shape and slightly fragmented.
采用简单的水包油乳化溶剂蒸发法制备了负载依托泊苷的聚乳酸 - 乙醇酸共聚物（PLGA）50:50、PLGA 75:25和聚己内酯（PCL）的可生物降解微球，并通过粒径分析和显微镜进行表征。研究了药物与聚合物比例对依托泊苷包封率的影响。在所有三种类型的微球中，聚己内酯微球（PCL MS）表现出最高的包封率（94.64%），其次是PLGA 75:25微球（PLGA 75:25 MS）（88.64%）和PLGA 50:50微球（PLGA 50:50 MS）（79.19%）。1:20的药物与聚合物比例使所有三种类型的微球获得最高的包封率。在含有0.1%吐温80的pH 7.4磷酸盐缓冲液（pH 7.4 PB）中研究了依托泊苷从三种微球制剂中的体外释放。微球呈现出初始突释，其中PLGA 50:50 MS的突释最高，PCL MS的突释最低。PCL MS微球比其余制剂表现出更低且更缓慢的药物释放。依托泊苷从所有三种微球制剂中的释放均符合Higuchi扩散模式。在溶解介质中放置28天的微球形状不规则且略有破碎。
