Systematic Optimization of Tinospora cordifolia Extract Gel Via Box-Behnken Design Using a DoE Framework

Background

The design and optimization of a Tinospora cordifolia (Giloy) extract-loaded topical gel was carried out to explore its anti-inflammatory potential using a Box-Behnken Design (BBD). The study focused on improving formulation characteristics for effective topical delivery.

Materials and Methods

Three formulation variables-Carbopol 934 (A), triethanolamine (B), and propylene glycol (C) were optimized based on their effects on viscosity, retention time, and phenolic content. ATR-FTIR analysis was performed to assess physicochemical compatibility. Antimicrobial activity was evaluated against Staphylococcus epidermidis, Escherichia coli, and Candida albicans using MIC and agar well diffusion methods. In vitro drug release studies were also conducted.

Results

The optimized formulation containing Carbopol 934 (1.5% w/w), triethanolamine (1.0% w/w), and propylene glycol (15.0% w/w) showed a pH of 6.52, viscosity of 52,381 cP, and retention time of 146.3±4.1 sec. It exhibited phenolic content of 18.53%, spreadability of 25 g·cm/sec, and extrudability of 20 g. MIC values were 625 µg/mL for Staphylococcus epidermidis, 1250 µg/mL for Escherichia coli, and 2500 µg/mL for Candida albicans. Extract release reached approximately 100% within 4 hr, following Higuchi kinetics (R²=0.952).

Conclusion

The optimized Giloy gel demonstrated satisfactory physicochemical properties, antimicrobial activity, and short-term stability, indicating its potential as an effective topical anti-inflammatory formulation.