In Vitro and In Vivo Characteristics of Olive Oil as Excipient for Topical Administration.

Oily excipients are vital components of dermatological products. In this study, the in vitro and in vivo characteristics of Wild Olive Oil (WOO) were compared with two other types of olive oils: Extra Virgin Olive Oil (EVOO) and Virgin Olive Oil (VOO). This work has also included Liquid Paraffin (LP) and Rosehip Oil (RO) as reference oils. Melatonin was used in the study as a model drug to demonstrate the antioxidant capacity of the oils. The melatonin carrier capacity and antioxidant performance was related to the degree of unsaturation of the oils and was highest for RO and WOO and lowest for LP. However, the most stable oil to oxidation was LP. The in vivo performance of the oils in the skin of eight healthy volunteers was investigated with a dermoanalyser. The highest increment of oil and hydration in the skin was obtained with RO. The lowest perception of oiliness was described for WOO, which produced the highest increase in elasticity of the skin area where it was applied. An in vitro-in vivo correlation was therefore performed through multivariable analysis (MVA).