Degradation kinetics of 4-dedimethylamino sancycline, a new anti-tumor agent, in aqueous solutions

The kinetics of degradation of the new anti-tumor drug, 4-dedimethylamino sancycline (col-3) in aqueous solution at 25 degrees C were investigated by high-pressure liquid chromatography (HPLC) over the pH-range of 2-10. The influences of pH, buffer concentration, light, temperature, and some additives on the degradation rate were studied. The degradation of col-3 was found to follow first order kinetics. A rate expression covering the degradation of the various ionic forms of the drug was derived and shown to account for the shape of the experimental pH-rate profile. Under basic conditions, the degradation of col-3 involves oxidation, which is catalyzed by metal ions and inhibited by EDTA and Sodium bisulfite. (C) 1999 Elsevier Science B.V. All rights reserved.