Kinetic study employing UV derivative spectroscopy of DM-COOK antitumor and antimetastatic agent

The hydrolysis of p-(3,3-dimethyl-l-triazeno)benzoic acid potassium salt (1;DM-COOK) a highly active antimetastatic and anti-disseminative agent, has been studied in buffered aqueous solution over a pH range of 2.8-8.8 degrees C. The pH dependence of the pseudo first-order rate constants showed two different routes. Under physiological conditions the hydrolysis reactions are carried out by acid catalysis. A procedure based on fourth-order derivative UV spectroscopy (D4) has been developed for the calculation of the kinetic constants at pH greater than or equal to 4.00 and no spectral interferences resulted from decomposition products. The application of derivative UV spectroscopy proved to be suitable fpr rapid, sensitive and reproducible studies of hydrolysis of this class of compounds.