维生素E聚乙二醇琥珀酸酯还原敏感前药胶束的制备及药物控释性能

Redox-sensitive TPGS prodrug micelles for controlled drug release

摘要:

本文制备了还原敏感TPGS-SS-MTX前药胶束，由抗肿瘤药物甲氨蝶呤（MTX）与维生素 E 聚乙二醇琥珀酸酯（TPGS）以二硫键为连接键合而成。核磁共振氢谱（1HNMR）表明TPGS与MTX以1:0.92摩尔比键合。动态光散射（DLS）及电镜分析（SEM/TEM）显示胶束呈单分散球形结构，平均粒径213 nm，zeta电位为-19.6 mV。临界胶束浓度（CMC）低至18.32 μg/mL。胶束具有生理环境下稳定性高，GSH环境下粒径增大的特点。此外，前药胶束中MTX载药率高达48.09%。体外释药表明GSH敏感释药行为，在10 mmol/L GSH（模拟肿瘤细胞内环境）条件下，72 h时 MTX 的释放率达82.1%，是正常生理环境的6倍。此外，生物学评价证实TPGS具有选择性细胞毒性，对L929正常细胞保持高存活率，而对CT26肿瘤细胞呈现剂量依赖性抑制；前药胶束在10 mmol/L GSH中使CT26细胞24 h抑制效率较L929细胞提升1.47倍，归因于GSH触发的二硫键断裂及药物释放。激光共聚焦(CLSM)实验表明负载药物的前药胶束可有效被细胞内吞并在细胞内还原敏感释放药物。

Abstract:

In this study, a reduction-sensitive TPGS-SS-MTX prodrug micelle was successfully prepared by conjugating the antitumor drug methotrexate (MTX) with vitamin E polyethylene glycol succinate (TPGS) via a disulfide bond. Structural characterization of the prodrug with successful MTX conjugation was performed with a 1:0.92 conjugation ratio by 1HNMR analysis. Besides, prodrug micelles were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and so on. The results indicated that the prodrug micelles had a spherical structure with an average size of 213 nm, and zeta potential of -19.6 mV. Moreover, the prodrug micelles had low critical micelle concentration (CMC) of 18.32 μg/mL. The prodrug micelle showed excellent colloidal stability under physiological conditions and GSH-triggered size aggregation behavior. The prodrug micelles achieved a high MTX loading efficiency of 48.09%. In vitro drug release studies highlighted the GSH-sensitive behavior: under simulated tumor microenvironment conditions (10 mmol/L GSH), the cumulative MTX release reached 82.1% at 72 h, which was 6-fold higher than that in normal physiological conditions (0 mmol/L GSH). Biological evaluations further validated the selective cytotoxicity of TPGS, maintaining high viability in L929 normal cells while exhibiting dose-dependent growth inhibition in CT26 tumor cells. The prodrug micelles enhanced CT26 cell inhibition efficiency by 1.47-fold under 10 mmol/L GSH (24 h), attributed to GSH-triggered disulfide bond cleavage and subsequent drug release. Confocal laser scanning microscopy (CLSM) confirmed efficient cellular internalization of drug-loaded micelles and redox-sensitive intracellular drug release, aligning with the proposed tumor microenvironment-responsive delivery mechanism.