Determination of sixteen UV filters in suncare formulations by high-performance liquid chromatography.

Reversed-phase liquid chromatography (RP-LC) with UV detection was developed for the simultaneous determination of 16 organic UV filters worldwide authorized in suncare products. The filters determined were: 4-aminobenzoic acid, homosalate, benzophenone-3,2-phenylbenzimidazole-5-sulfonic acid, terephthalidene dicamphor sulfonic acid, 4-tert-butyl-4'-methoxy-dibenzoylmethane, octocrylene, 2-ethylhexyl-4-methoxycinnamate, isoamyl-p-methoxycinnamate, ethylhexyltriazone, drometrizole trisiloxane, diethylhexyl butamido triazone, 3-(4-methylbenzyliden) camphor, 2-ethylhexylsalicylate, 2-ethylhexyl-4-dimethylaminobenzoate and benzophenone-4. A C18 stationary phase and a gradient of ethanol-aqueous acetate buffer containing 0.2 mM of EDTA, was used with a flow-rate of 1.0 ml/min. UV detection was carried out at 313 and 360 nm. The analysis required 32 min and the limits of detection were between 30 and 4130 mg/kg in the original suncare product. Tween 80 was used to break down the different emulsions in order to procure a proper extraction of the UV filters. The method was validated for UV filters in three matrices, oil, water-in-oil emulsion and oil-in-water emulsion. Recoveries from spiked samples were 86-113% depending on the matrix used.