Formulations containing Artemisia afra Jacq. Ex Willd for topical delivery

Abstract

Abstract Artemisia afra (A. afra) is an herbal medicine, traditionally prepared as a tea infusion, used for centuries in African countries to treat a vast number of ailments. This herb contains an ample amount of known and unknown compounds and has antibacterial, anti-viral and anti-fungal properties; hence, topical treatment was considered. A liquid chromatography mass spectrometry (LC-MS/MS) method was developed and validated to detect the six selected marker compounds used during this study: two organic acids (4,5-dicaffeoylquinic acid (DCQA) and chlorogenic acid (CGA), two flavonoids (luteolin and quercetin) and two coumarins (scopoletin and scopolin). The formulations selected had to accommodate the hydrophilic nature of the A. afra infusion; therefore, there was an infusion, hydrogel and emulgel selected. The hydrogel and emulgel contained a gelling agent, xanthan gum, whereas the emulgel additionally contained a chemical penetration enhancer, evening primrose oil (EPO), to improve penetration through the lipophilic stratum corneum. The characterisation of the semi-solid formulations was to ensure skin application suitability. Membrane release studies confirmed sufficient release of the different markers from the formulations. During the in vitro skin diffusion studies, the discovery was that the infusion had the highest median flux and amount per area diffused compared to the other formulations. Thereafter, there was tape stripping performed, and established that there were markers present in the stratum corneum-epidermis (SCE) and epidermis-dermis (ED). The testing of cytotoxicity was to determine the safety of topical delivery, and the finding was that A. afra showed no cytotoxicity at the levels tested.