Athree-hourtestforrapidcomparisonofeffectsofmoisturizersandactiveconstituents(urea). Measurement of hydration, scaling and skin surface lipidization by noninvasive techniques

Abstract

An in vivo skintestforrapidcomparisonof the efficacy ofmoisturizersis introduced.Testsubstances were applied to flexor side forearm skin, and measurements by non-invasive techniques were performed after 3 h. As indicators of epidermal hydration, the electrical conductance and capacitance were measured. To quantify theeffectson scale pattern, D-Squame tapes were scored and the optical transmission measured. Moreover, skin surface lipids resulting from lotion lipids were measured. Lotions and different concentrations ofureacould be ranked in a consistent way, viz. untreated skin < vehicle < 3%urealotion < 10%urealotion.Ureawas concluded to be very potent as a skin humidifier and as a descaling agent, particularly in 10% concentration. Humidity characteristics correlated much better with the concentration ofureathan with lipidization of the skin surface due to lotion lipids. A 3-hourtestperiod was sufficient for the evaluation of theeffectsofmoisturizerson both epidermal hydration and scale pattern. With arapidtestmethod, sources of variation such as diurnal and day-to-day variations, dosage and non-compliance are easily controlled. Further, by using non-invasive methods, the assessment has been rendered objective.