Evaluation of thermal stability and sun protector factor values in vitro in O/W emulsions containing Benzophenone-3 and Avobenzone

Abstract

The purpose of this work is to study the thermal stability of benzophenone-3 and avobenzone in the presence and in the absence of TiO2, in O/W emulsions for sunscreens products. The emulsions were stored in glass containers at 40 °C and 75 % RH and at room temperature. Concomitantly the Sun Protector Factor (SPF) value was evaluated in vitro. These formulations seem to be more stable in the presence of diethylhexyl syringylidene malonate and titanium dioxide and silica. Avobenzone and benzophenone-3 seem to be less stable in the presence of caprylic capric triglyceride though this excipient increases the SPF in vitro value. Thus, the aim of this study was to evaluate the thermal stability by HPLC and the efficacy of formulations containing chemical filters, a physical filter and an antioxidant measuring the SPF in vitro value.