No abstract

Many substances of natural origin are contained in pharmaceutical and cosmetic formulations, but lately extra virgin olive oil (EVOO) or EVOO-derived compounds like tyrosol, hydroxytyrosol or oleuropein, thanks to their renowned and long-established outstanding therapeutic and health giving virtues, have made them some of the most interesting products in this field. Nowadays many hydroxytyrosol-based topical formulations are commercialized and over time several analytical methods have been developed. However, new cosmetic formulations containing an olive extract tritated in hydroxytyrosol conveyed in EVOO have recently appeared on the market creating the need to develop and validate a new method that allows the active compound to be extracted and analyzed precluding any interference due to the presence of other compounds naturally present in the EVOO as well as from the co-formulant agents employed, and this has been the goal of our study.Analytical determination was performed by RP-HPLC coupled with DAD detection. Various chromatographic parameters, namely column stationary phase, mobile phase, pH and solvent composition, oven temperature and different clean-up variables were studied. The best chromatographic separation was obtained under the following conditions: a reverse phase C18 column maintained at 25°C with a gradient elution program using acetic acid 0.2% and methanol as mobile phase pumped at 1.5 mL min −1 . Detection wavelength was set at 280 nm and the total run time required was 15 min. The high degree of accuracy (98.8%-100.1%) and precision (1.44%-1.68%) achieved using the evaluated method along with the low limits of detection and quantification (2.49 ppm and 3.97 ppm respectively) and the broad linear range observed allowed the target analyte to be satisfactorily determined in new semi-solid formulation containing hydroxytyrosol conveyed in EVOO while avoiding any matrix effect.