Analysis of octyl methoxycinnamate in sunscreen products by a validated UV-spectrophotometric method

An inexpensive, rapid method for the determination of octyl methoxycinnamate (OMC) in sunscreen products using ultraviolet-spectrophotometry has been developed and validated according to International Council for Harmonisation and Association of Official Analytical Chemists guidelines. Methanol was the optimal solvent used with a linearity range of 4-12 mu g/ml (r = 0.999) being obtainable. The accuracy of the method is highlighted by the % recovery (98.23-98.50) and relative standard deviation (%RSD, 0.12), and it is widely applicable to prototype products composed of oil in water, and water in oil emulsions. Mineral oils containing low, intermediate, and high OMC levels (1%, 4%, and 7.5%) gave recovery percentages of 99.76-100.76 with %RSD of 0.02-0.28. In addition, this method is repeatable and affords a high degree of precision (%RSD = 0.12 and 0) with 96.08-99.27% recovery. The method is suitable for quality assurance of suncare product formulations, and could be applicable to product development and validation.