Stability Analysis of Three UV-Filters Using HPLC

Abstract UV-absorbing substances are widely used in sunscreens to filter out ultraviolet radiation in sunlight. These substances need to be stable in sunscreens in order to obtain the expected protection during the shelf-life of the products. A conveniant HPLC method for the separation and quantification of three common UV-filters in a sunscreen emulsion is presented. Using this method the stability of benzophenone-3, butylmethoxy dibenzoylmethane and octyl methoxycinnamate was determined. Calibration curves for the three UV-filters showed linear response in the interval 0.03 to 30 μg. The absolute recovery of the spiked sample was close to 100 %. The shelf life data indicate good stability of the filters.