Departamento Sistemas de Baja Dimensionalidad, Superficies y Materia Condensada. Instituto de Química Física Rocasolano, CSIC, Madrid, Spain.
J Microencapsul. 2012;29(7):626-35. doi: 10.3109/02652048.2012.676091. Epub 2012 Apr 12.
Poly(N-isopropylacrylamide) (PNIPA) and Poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPA-co-AA)) microgels loaded with 5-aminolevulinic acid (ALA) were prepared by the spray-drying method. The amount of drug loaded was 290 µg ALA/mg microgel for PNIPA and 244 µg ALA/mg microgel for P(NIPA-co-AA) microgels. Maximum in vitro drug release took place within 15-30 min for PNIPA and 1-1.5 h for P(NIPA-co-AA) microgels as a function of pH, at 37°C. Transdermal delivery from microgels showed permeation fluxes 10 times higher than the passive diffusion flux. The cytotoxicity of microgels synthesized in HeLa cells after the application of photodynamic therapy (PDT) was superior compared with the administration of ALA in solution alone. Finally, the use of these microgels as a delivery vehicle for ALA constitutes a system capable of enhancing its topical administration and PDT effectiveness.
聚（N-异丙基丙烯酰胺）（PNIPA）和聚（N-异丙基丙烯酰胺-共-丙烯酸）（P（NIPA-co-AA））载 5-氨基酮戊酸（ALA）的微凝胶通过喷雾干燥法制备。药物载量为 290μg ALA/mg 微凝胶用于 PNIPA 和 244μg ALA/mg 微凝胶用于 P（NIPA-co-AA）微凝胶。在 37°C 下，PNIPA 的最大体外药物释放发生在 15-30 分钟内，而 P（NIPA-co-AA）微凝胶的最大体外药物释放发生在 1-1.5 小时内，这与 pH 值有关。微凝胶的透皮给药显示出比被动扩散通量高 10 倍的渗透通量。与单独在溶液中施用 ALA 相比，HeLa 细胞中合成的微凝胶在光动力疗法（PDT）后表现出更高的细胞毒性。最后，这些微凝胶作为 ALA 的递送载体构成了一种能够增强其局部给药和 PDT 效果的系统。
