The present study aimed to investigate the thermal- and pH-dependent gelation behavior of gelatin/HPMCP blends using ultraviolet (UV) spectrophotometry, viscoelasticity, and dynamic light scattering (DLS). We found that the release of lisinopril from gelatin/HPMCP gels can be inhibited at low pH. UV spectrophotometric analysis showed that pH had a significant effect on the transparency of aqueous HPMCP systems and gelatin/HPMCP gels. The viscoelastic patterns of gelatin/HPMCP at pH 4.6 considerably differed from those of gelatin/HPMCP at pH 5.2 and 6.0. DLS measurements showed that HPMCP molecules in low concentrations underwent strong aggregation below pH 4.8. Such HPMCP aggregation induces a physical barrier in the matrix structures of the gelatin/HPMCP gels, which inhibits the drug release at pH 1.2. This hydrogel delivery system using polymer blends of gelatin/HPMCP can be used in oral gel formulations with pH-responsive properties.

本研究旨在使用紫外 (UV) 分光光度法、粘弹性和动态光散射 (DLS) 研究明胶/HPMCP 混合物的热和 pH 依赖性凝胶化行为。我们发现赖诺普利从明胶/HPMCP 凝胶中的释放可以在低 pH 值下受到抑制。紫外分光光度分析表明，pH 值对 HPMCP 水溶液系统和明胶/HPMCP 凝胶的透明度有显着影响。pH 4.6 时明胶/HPMCP 的粘弹性模式与 pH 5.2 和 6.0 时明胶/HPMCP 的粘弹性模式有很大不同。DLS 测量表明，低浓度的 HPMCP 分子在低于 pH 4.8 时发生强烈聚集。这种 HPMCP 聚集会在明胶/HPMCP 凝胶的基质结构中产生物理屏障，从而在 pH 1.2 时抑制药物释放。