Second-derivative UV spectrophotometric assay for determining the degradation kinetics of 3-bromo- N-bromo- N-(3,4-dimethyl-5-isoxazolyl-4-amine)-1,2-naphthoquinone

The application of the second-derivative UV spectrophotometry for determining the stability of 3-bromo- N-bromo- N-(3,4-dimethyl-5-isoxazolyl-4-amine)-1,2-naphthoquinone in ethanolic solutions is described. The validity of this method was evaluated using synthetic mixtures of the intact drug and its degradation products and by statistical analysis of the calibration data. In order to verify the usefulness of this method for stability studies, recovery experiments by the standard addition method were also carried out.