Prospecting In Vitro Antioxidant and Photoprotective Properties of Rosmarinic Acid in a Sunscreen System Developed by QbD Containing Octyl p-Methoxycinnamate and Bemotrizinol

Abstract

Progressively growing diagnoses of skin cancer trigger public health concerns about excessive sun exposure, awareness of the deleterious effects of ultraviolet (UV) radiation on the skin, and the proper use of sunscreens. Studies show that bioactive molecules, such as rosmarinic acid (RA), may potentiate the photoprotective and antioxidant activity of topical formulations. This research presents the application of the concepts of quality by design (QbD) to evaluate the critical parameters of quality and the development of an optimized cosmetic formulation with RA by means of an understanding of product design space. Samples were developed using design of experiments (DoE) and they were evaluated for in vitro antioxidant activity and photoprotective efficacy, as well as for photostability through artificial irradiation. We were able to achieve the RA performance regarding antioxidant and SPF properties through in vitro experiments. We obtained the equations for predicting the in vitro antioxidant activity and SPF. Considering our sunscreen system, developed with octyl p-methoxycinnamate and bemotrizinol, the presence of RA increased its antioxidant capacity; however, the in vitro SPF was reduced when both UV filters were used. The development of multifunctional sunscreens is of utmost importance; moreover, there is a need for the rational development of formulations that ensure representative statistical tests of the effects and interactions among the components of a formulation on the desired critical quality attributes, including efficacy.