Simultaneous determination of tetracaine and its degradation product, p-n-butylaminobenzoic acid, by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for the simultaneous determination of tetracaine hydrochloride and its hydrolytic degradation product, p-n-butylaminobenzoic acid. Separation was achieved using a mu Bondapak C18 column and the eluent, water-acetonitrile-methanol (60:20:20), containing 0.06% (v/v) sulfuric acid, 0.5% (w/v) sodium sulfate, and 0.02% (w/v) sodium heptanesulfonate, at a flow rate of 2 ml/min Salicylic acid and propiophenone were used as internal standards. The UV detector response at 305 nm was linear for tetracaine hydrochloride in the 0.4--2.0-mg/ml range and for p-n-butylaminobenzoic acid in the 0.003--0.02-mg/ml range. The method is simple and precise.