Optimization of Gelling Agent and Sunscreen Activity Test on 4-OH-chalcone Gel Using In Vitro Method

4-OH-chalcone is suspected of absorbing and reducing ultraviolet radiation intensity exposed to the skin. It was formulated in gel dosage form using a combination of 0.50-1.00% w/w carbopol content, 19-20% w/w propylene glycol content, and 0.50-1.00% w/w CMC-Na content. This study aimed to optimize the three gel bases and evaluate the physical properties, physical stability, and activity of 4-OH-chalcone gel as a sunscreen using in vitro method. Simplex Lattice Design (SLD) method was used to optimize the gel base using Design Expert software version 10.0. The activity of 4-OH-chalcone gel as sunscreen was determined spectrophotometrically by determining the Sun Protecting Factor (SPF) value, percent transmission of erythema (% TE), and percent transmission of pigmentation (% TP). Data were analyzed statistically using SPSS Statistical software. The optimum formula of 4-OH-chalcone gel was 0.50% w/w carbopol content, 0.50% w/w carboxymethylcellulose sodium content, and 20.0% w/w propylene glycol content which had a pH of 5.59, viscosity of 37.4 dPa.s, spreadability of 28.8 cm2, adhesive time of 1.28 seconds, SPF value of 28.65, %, TE value of 16.44%, %TP value of 0.24%, and relatively stable physical properties.