Polylactic acid (PLA) and poly(lactic-co-glycolic) acid (PLGA) are two commonly applied biodegradable polymers for the preparation of nanocomposites used in drug-delivery systems. However, these polymers lack desirable attributes such as resistance to aggregation during long-term storage due to lyophilisation. To improve their efficacy, in this work, PLA and PLGA were encapsulated within a shell of poly(N-isopropylacrylamide) (pNIPAM) using a single emulsion technique followed by an aqueous free radical precipitation polymerisation process, yielding core–shell PLA/PLGA–pNIPAM nanocomposites. The nanocomposites were characterised using zeta potential, dynamic light scattering, and transmission electron microscopy analyses and were further applied as a delivery system for ramipril, an antihypertensive drug. The drug-loaded PLGA–pNIPAM core–shell nanoparticles exhibited a higher drug content (91%) and entrapment efficiency (78%) than their PLA counterparts. An in vitro release study of the formulations at pH 7.3 in phosphate-buffered saline indicated that PLGA was more efficient than PLA with a sustained release of 86% of ramipril from the polymer matrix within 24 h. Furthermore, to determine the release kinetics, the data were fitted to Korsmeyer–Peppas and Higuchi models; the release of ramipril from the polymer matrix followed zero-order rate kinetics and an anomalous (non-Fickian) diffusion mechanism.

聚乳酸（PLA）和聚乳酸-乙醇酸共聚物（PLGA）是两种常用的可生物降解的聚合物，用于制备药物递送系统中使用的纳米复合材料。但是，这些聚合物缺乏合乎需要的特性，例如由于冻干而在长期储存过程中不耐聚集。为了提高其功效，在这项工作中，将PLA和PLGA封装在了聚（N-异丙基丙烯酰胺）（pNIPAM）使用单乳液技术，然后进行水性自由基沉淀聚合过程，得到核-壳PLA / PLGA-pNIPAM纳米复合材料。使用zeta电位，动态光散射和透射电子显微镜分析对纳米复合材料进行表征，并将其进一步用作抗高血压药物雷米普利的递送系统。载有PLGA-pNIPAM核-壳纳米颗粒的药物比PLA药物具有更高的药物含量（91％）和包封率（78％）。在磷酸盐缓冲液中pH 7.3的制剂的体外释放研究表明，PLGA比PLA更有效，在24小时内从聚合物基质中持续释放了86％的雷米普利。此外，要确定释放动力学，数据符合Korsmeyer-Peppas和Higuchi模型；雷米普利从聚合物基质中的释放遵循零级速率动力学和异常（非菲克）扩散机制。