Formulation, characterization and optimization of peel-off gel of soybean extract as a face mask

Abstract

A peel-off mask is a type of dosage form that is gently applied onto the skin and peeled off after a few minutes. It is one of the most popular skincare products used to treat facial-related conditions. This study is aimed at designing and optimizing a peel-off facial mask formulation containing 20% w/w of soybean extract by response surface methodology (RSM). The peel-off mask was formulated using different concentrations of polyvinyl alcohol (PVA), ethanol, and carbomer 940. The isoflavonoids content of the soybean extract was determined using spectrophotometric method. Physicochemical properties (homogeneity, colour, odour, and pH) of the peel-off mask formulation were examined. Other parameters investigated include drying time, applicability, film-forming performance, and loading efficiency. The stability of the formulation was also investigated. The results showed that the PVA and ethanol concentrations significantly affected the drying time of the formulation. The PVA concentration and its quadratic term significantly influenced applicability of the formulation. The amount of carbomer in the formulation had the most significant impact on how well the film formed. The optimized formulation is composed of 20% soybean extract, 12.03% PVA, 8.36% ethanol, and 0.52% carbomer. Stability test results show that low temperature (5 ± 1°C) and room temperature, protected from sunlight (22 ± 2°C) have no effect on the stability of the formulation, and that phenoxyethanol at 1.0% w/w could preserve the formulation from microbial degradation under various storage conditions. Therefore, RSM was a helpful way to figure out the best conditions for making soybean peel-off facial masks.