Das, Sudip, and Koushik Sen Gupta. “A Comprehensive Review on Natural Products As Chemical Penetration Enhancer”. Journal of Drug Delivery and Therapeutics 11, no. 5-S (October 15, 2021): 176–187. Accessed February 1, 2026. https://jddtonline.info/index.php/jddt/article/view/5077.