Development and Validation of a Reversed Phase HPLC Method for Quantitative Analysis of bis-Isoxazolylnaphthoquinone

CRISTINA S. ORTIZ Y M. M. DE BERTORELLO

ELSEVIER SCIENCE BV

Año: 1998 p. 1537 - 1537

he goal of this study was to determine the kinetic parameters involved in the decomposition of 2-(5-methyl-4-isoxazolylamino)- N-(5-methyl-4-isoxazolyl)-1,4-naphthoquinone-4-imine (1) in aqueous solution and to identify the main degradation products. An isocratic HPLC assay was used to study the degradation rate of 1. The products of hydrolysis were identified by comparison of their retention times those of authentic samples. The amount of 1 and the two degradation products resulting from storage of 1 in various buffer solutions was followed in function of time by a reversed-phase HPLC stability-indicating method. The observed degradation rates followed pseudo-first-order kinetics al constant pH, temperature and ionic strength. The log k - pH-profile was constructed at 35 C from the first-order rate constants obtained from studies at pH values ranging from 0.88 to 10.80 (u=0.5 M). Hydrolysis in the acidic and alkaline media resulted in the formation of two degradation products in each