Formulation development and preliminary biological evaluation of a menthol modified thermoresponsive tamoxifen sol-gel.

Localized drug delivery strategies offer potential advantages in improving therapeutic concentration at tumor sites while minimizing systemic exposure. In this study, a thermoresponsive poloxamer based sol-gel system incorporating tamoxifen citrate with L-menthol was developed and characterized for potential intratumoral application. The formulation was prepared using the cold method and optimized through response surface methodology\. The optimized system exhibited rapid sol-gel transition at 38.5 °C with gelation time around 37s, acceptable syringeability, pH compatibility with mildly acidic tumor conditions, and uniform drug content (93-96%) with high encapsulation efficiency (88-93%). In vitro release studies demonstrated sustained tamoxifen release over 48 h, best described by the Korsmeyer-Peppas model (n = 0.366), indicating diffusion-controlled release. Physicochemical analyses (FTIR, DSC, XRD, SEM) confirmed drug excipient compatibility and partial amorphization within the polymeric matrix. Molecular docking provided preliminary insight into potential interactions with breast cancer associated proteins. In vitro cytotoxicity in MCF-7 cells showed reduced IC₅₀ values for the menthol containing formulation compared to tamoxifen alone. Acute toxicity evaluation in mice indicated acceptable short-term tolerability. Overall, this system represents a promising localized delivery platform warranting further mechanistic and in vivo efficacy investigations.