Abstract

Dual-responsive nanocapsules of poly (N-isopropyl acrylamide (NIPAM)-co-acrylic acid (AA)-co-2-hydroxyethylmethacrylate (HEMA)) were synthesized by precipitation polymerization. The dual (temperature- and pH-)-responsive nanocapsules were fabricated using NIPAM as a temperature-sensitive monomer, AA as a pH-responsive monomer and 5-fluorouracil (5-FU) as a model drug. The P(NIPAM-co-AA-co-HEMA) nanocarrier had a hollow nanocapsule structure with average diameter of about 70 nm and a shell thickness of about 10 nm. The nanocarrier exhibited good loading capacity (32.6%) and considerable encapsulation efficiency (57.3%) for 5-FU by physical entrapment. The zeta potentials of nanocapsules were observed from −30.7 to −35.2 mV after the incorporation of 5-FU. The cumulative release of nanocapsules reached at 88.7% (37 °C, pH 5.8). The overall drug release performance revealed that the drug release behavior was efficient, sustainable and stable at 37 °C and pH 7.4. In addition, the release mechanism analysis suggested that the drug release behavior is more dependent on pH than temperature.

摘要

通过沉淀聚合合成了聚（N-异丙基丙烯酰胺（NIPAM）-共-丙烯酸（AA）-共-2-羟乙基甲基丙烯酸酯（HEMA））的双响应纳米胶囊。使用 NIPAM 作为温度敏感单体、AA 作为 pH 响应单体和 5-氟尿嘧啶 (5-FU) 作为模型药物制备双（温度和 pH 值）响应纳米胶囊。P(NIPAM-co-AA-co-HEMA)纳米载体具有中空纳米胶囊结构，平均直径约70 nm，壳厚度约10 nm。纳米载体通过物理包埋对 5-FU 表现出良好的负载能力（32.6%）和可观的包封效率（57.3%）。在掺入 5-FU 后观察到纳米胶囊的 zeta 电位从 -30.7 到 -35.2 mV。纳米胶囊的累积释放达到 88.7%（37°C，pH 5.8）。整体药物释放性能表明药物释放行为在 37°C 和 pH 7.4 下是高效、可持续和稳定的。此外，释放机制分析表明药物释放行为更多地依赖于pH而不是温度。