Formulation and Evaluation of Ethosomal Nanoparticles of Avobenzone for Improved Sunscreen Efficacy

Abstract

Ethosomes entrapping avobenzone were prepared using cold method and the effect of varying concentration of ethanol was considered for obtaining an optimized formulation. Lecithin (2%w/w) was used as the phospholipid to provide the structure to the vesicles and propylene glycol (10%) was used as the permeating agent. The vesicles were found to be of spherical to irregular shape ranged from 1.11 µm to 1.6 µm in size. The drug entrapment in the ethosomes was studied by analyzing the unentrapped drug spectrophotometrically. The in vitro permeation study suggested that the maximum permeation in the egg membrane occurred in AET3 (0.40 mg/cm2) with 30% ethanol concentration. It was observed that only about 2% degradation occurred at room temperature and all formulations were almost stable at 8° and 4° with only 1.3% degradation of avobenzone thereby proving the stability of the developed system. The best ethosomal formulation (AET3) was incorporated into gel base to obtain sunscreen gels and the results revealed a good protection of the ethosomal gel when 2% carbopol was used as the gelling base. It could be concluded that incorporation of avobenzone in the ethosomal carrier and formulating the same as gel formulation might help in reducing the dose of avobenzone as well as improving the sunscreen efficacy (sun protection over enhanced duration).