[Investigation, identification and dosage of local anesthetics and antihistaminics in cosmetic products].

A rapid and accurate reversed-phase HPLC method for separation and simultaneous quantitation of some local anesthetics, antihistamines and preservatives in skin cosmetics is described. The investigated compounds (procaine, lidocaine, mepivacaine, bupivacaine, benzocaine, brompheniramine, benzoic acid, methyl, ethyl and propyl p-hydroxybenzoate, o-phenylphenol) are extracted by ultrasonic treatment in methanol from cosmetic form. Methanol-aqueous orthophosphoric acid (pH 2.8) containing 0.9% dibutylamine has been used as eluent. The influence of different percentages of methanol on chromatographic behaviour has been studied using both isocratic conditions and gradient elution program. The gradient program allows a rapid resolution and quantitation also for acidic preservatives.