Shandong Science

   

Formulation optimization and characterization of a thermosensitive enema gel containing puerarin in a solid dispersion

WEI Huilin, FU Yan, DAI Anlin, CHEN Yajuan, ZHANG Zengni, ZHOU Xia, WAN Jun*   

  1. School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, China
  • Received:2025-12-09 Accepted:2026-01-12 Online:2026-10-19
  • Contact: WAN Jun E-mail:wjun1013@swjtu.edu.cn

Abstract: In this study, a thermosensitive enema gel containing puerarin in solid dispersion form was prepared to address the poor solubility and low bioavailability of puerarin. Through single-factor experiments and using the Box-Behnken response surface methodology, we evaluated multiple indicators of the gel such as gelation temperature and gelation time, and identified its optimal formulation: 17.74% poloxamer 407, 1.36% poloxamer 188, 0.96% sodium alginate, and 0.06% anhydrous calcium chloride. Material characterization of this optimized formulation showed that the gel had a gelation temperature ranging from 36°C to 39°C, which is close to physiological body temperature, allowing the gel to rapidly transform into a semi-solid gel state at body temperatures. Scanning electron microscopy indicated that the gel possessed a regular three-dimensional porous network structure. Fourier transform infrared spectroscopy analysis showed that Puerarin existed in an amorphous state in both the solid dispersion and the gel, and showed good compatibility with the carrier materials without significant chemical interactions. Rheological tests further demonstrated that the gel exhibited elastic properties after the phase transition, indicating good gel strength. In vitro swelling and degradation experiments showed that the gel had excellent water absorption and swelling capacity in a simulated physiological environment, with a maximum swelling rate of over 80%. Additionally, during the degradation process, the mass retention rate of the gel remained above 20% after 24 h, and the degradation curve showed a trend of initial rapidity followed by gradual degradation, indicating its potential for sustained drug release. In conclusion, these results suggest that the enema gel containing puerarin in a solid dispersion form possessed marked temperature-sensitive gelation properties, favorable swelling and degradation characteristics, and a stable three-dimensional porous structure, providing a promising novel strategy for improving the delivery of puerarin.

Key words:  , puerarin, solid dispersion, thermosensitive gel, enema, ulcerative colitis

CLC Number: 

  • R943

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