Assessment of in vitro methodologies to determine topical and transdermal delivery of the flavonoid quercetin

Abstract

To be effective against the oxidative damages induced by UVB irradiation in the skin, the drug needs to release from the formulation in which it was incorporated and reach the skin layers where the ROS are generated. Thus, it is very important the development of a robust and sensitive methodology to extract and quantify in different skin layers the antioxidant agent delivered from topical formulations. Therefore, in the present work suitable methods to extract and quantify quercetin in skin samples and receptor phase after in vitro penetration studies were developed. The results demonstrated that the recovery from two different layers of skin, the SC and [E+D], using two different methods of quantification (DPPH• assay and HPLC, respectively), was 93.8 % when the quercetin spiked dose was 50 µg/mL, 100.4 % when it was 100 µg/mL and 89.9 % for 250 µg/mL and the average recovery of the quercetin extraction from receptor phase when dichloromethane was used as extractor solvent was 96%. These results demonstrate that the described methods have a potential application to in vitro skin penetration studies of quercetin, since it showed to be accurate and sensitive.