Use of Simplex Lattice Design (SLD) in Optimizing HPMC and Propylene Glycol Gel Formula of Cinchonine as Antibacterial Against Cutibacterium Acnes (C. Acne)

The study focuses on optimizing a gel formulation containing Cinchonine, which has antibacterial properties against Cutibacterium acnes, using the Simplex Lattice Design (SLD). The research involved 8 different gel formulations to determine the optimal combination of ingredients, specifically HPMC and propylene glycol, based on spreadability, adhesion, viscosity, and pH. The optimal formula was found to be Cinchonine 1.5%, HPMC 2%, propylene glycol 13%, DMDM hydantoin 0.2%, and deionized water up to 100%. The gel demonstrated good spreadability, adhesive power, and viscosity, with a pH of 6.03. Stability tests showed a decrease in stability due to HPMC's sensitivity to high temperatures. The antibacterial activity was observed with inhibition zones of 7.75 mm at 18 hours and 5.59 mm at 24 hours. The gel was non-irritant and recommended for use twice daily.