Lactic acid clay mask formulation with plasticiser variations

Background: Lactic acid can inhibit the growth of acne-causing bacteria, moisturise, and remove dead skin cells. It can be formulated in clay mask preparations. One of the components of a clay mask is a plasticiser, which increases stability and controls the drying of preparations. Objective: To compare the effect of sorbitol and glycerol as plasticisers on the physical stability of lactic acid clay masks. Method: Clay masks were made with plasticiser concentrations of 0%, 2%, 3%, 4%, and 5%, then evaluated (organoleptic, homogeneity, pH, spreadability, viscosity, and flow properties) for three weeks. Furthermore, statistical analysis was done using two-way ANOVA and Friedman on the evaluation results with a p-value < 0.05. Result: Lactic acid clay mask with sorbitol had a range of pH values of 4.68–5.46, spreadability of 2.97–3.78 cm, drying speed of 10.92–15.08 minutes, and viscosity of 110.73–292.71 cps. In comparison, masks with glycerol had a pH value range of 4.64–5.54, spreadability of 2.67–3.73 cm, drying speed of 10.57–14.67 minutes, and viscosity of 107.417–282.55 cps. Conclusion: Sorbitol and glycerol had the same effectiveness as a plasticiser in increasing the physical stability of lactic acid clay mask preparations.