ZnO and quercetin encapsulated nanoparticles for sun protection obtained by miniemulsion polymerization using alternative co-stabilizers

Abstract

Abstract The present work evaluated the encapsulation of ZnO and quercetin in PBMA-PMMA-PS using the miniemulsion polymerization technique, aiming to develop nanoparticles with sun protection factor (SPF) and antioxidant activity (AA) for application in photoprotective lotions. In both formulations, octocrylene and green coffee oil were tested as co-stabilizing agents of the miniemulsion, being also encapsulated in the NPs, contributing to the SPF and AA of the obtained latexes. Spherical nanoparticles of homogeneous size, from 169 to 346 nm, and regular surfaces were obtained, remaining stable for at least 30 days. The encapsulation efficiency on the formulations tested was from 59 to 87% for ZnO, 47 to 51% for quercetin, 80 to 92% for octocrylene and 90 to 92% for green coffee oil. The quercetin and green coffee oil presented high antioxidant activity when encapsulated in polymeric NPs. The values of in vitro SPF was very good for formulations containing NPs-ZnO, with the best result for the simultaneous nanoencapsulation of ZnO and octocrylene (SPF 29 ± 5). The application of the NPs of quercetin and green coffee oil may promote an increment on SPF in vivo, reducing the damage caused to the skin by UV radiation, beyond the ability to scavenge the free radicals generated by ZnO.