Simultaneous Determination of Lonidamine, 1-(2,4-Dichlorobenzyl)-1h-indazole-3-carboxylic Acid, a New Antitumoral, and Its Impurity, N2 Substituted Isomer, by UV Derivative Spectrophotometry

Abstract A direct and fast analytical method for the determination of Lonidamine and its impurity of synthesis, the N2 alkylated isomer, by UV derivative spectrophotometry, is described. The procedure was defined by regression analysis for a high number of standard solutions. Linear relationships were obtained between mixture composition and maximum amplitude in <2D at 316 nm for Lonidamine quantitation, and peak trough 4D 226,234 and 4D 323,316 amplitudes by utilising polynomial equation for N2 isomer quantitation. The method, yielding accurate and precise results, was satisfactorily applied to laboratory mixtures and to a commercial formulation.