聚乙二醇单甲醚-聚乳酸-聚谷氨酸/聚赖氨酸的合成及其复合胶束的稳定性研究

制备等比例的聚乙二醇单甲醚-聚乳酸-聚谷氨酸(mPEG-PLA-PLG)和聚乙二醇单甲醚-聚乳酸-聚赖氨酸(mPEG-PLA-PLL)电中性聚离子复合胶束，依靠静电吸引提高原聚合物胶束聚乙二醇单甲醚-聚乳酸(mPEG-PLA)的结构稳定性。在mPEG-PLA的羟基末端引入氨基，分别与谷氨酸和赖氨酸的环化羧酸酐(NCA)发生开环反应，并且脱保护基制得目标产物，通过¹H NMR、IR确证其结构，荧光法比较载体改性前后的临界胶束浓度(CMC)。以透析法制备去氧鬼臼毒素聚合物胶束，HPLC法测定改性前后两种胶束的载药量和包封率，激光粒度仪和HPLC比较两种胶束25 ℃水浴过程中粒径和药物含量的变化。两者的CMC都较低，且载药量和包封率相近，但改性后胶束的稳定性增至原胶束的2倍以上，稳定性得到显著提高。

Preparation and stability of poly(ethylene glycol)monomethyl ether-poly(D, L-lactic acid)-poly(glutamic acid)/poly lysine triblock complex micelle

In order to improve the structural stability of the original polymeric micelles based on poly(ethylene glycol)monomethyl ether-poly(D, L-lactic acid)(mPEG-PLA)copolymer conjugate, the electroneutral polyion complex micelles with equal proportion of poly(ethylene glycol)monomethyl ether-poly(D, L-lactic acid)-poly(glutamic acid)(mPEG-PLA-PLG)and poly(ethylene glycol)monomethyl ether-poly(D, L-lactic acid)-poly lysine(mPEG-PLA-PLL)were prepared. The enhanced stability of the new micelle was attributed to electrostatic attraction. The target products were obtained by reacting the amino boded terminal hydroxyl group of mPEG-PLA with cyclic carboxylic acid anhydridesof glutamic acid and lysine, respectively through ring opening reaction, and subsequent protecting group removal. Their structures were identified by ¹H NMR and IR, and the differences of the critical micelle concentration(CMC)between mPEG-PLA and the modified polymers were measured by fluorescence. Dialysis was empolyed to prepare deoxypodophyllotoxin loaded polymeric micelles. The drug-loading capacity and encapsulation efficiency of mPEG-PLA micelles and electroneutral polyion complex micelle were determined by HPLC. The change of their particle size and drug content in 25 °C water bath were assessed by laser particle analyzer(dynamic light scattering)and HPLC, respectively. Both micelles had low CMC value and similar drug-loading capacity and encapsulation efficiency. However, the stability of the polymer complex micelles was two times higher than that of mPEG-PLA, which represented a significant enhancement.