DEGRADATION KINETICS OF IFOSFAMIDE IN AQUEOUS-SOLUTION

The degradation process of ifosfamide in aqueous solution at 50 degree s C was investigated at different concentrations, different pH ranges (3.6-9.8), different molarity and constant ionic strength. The observe d rate obtained by measuring the remaining intact ifosfamide was shown to observe first-order kinetics and was shown to be a specific acid a nd base catalysis. The pH rate profile in buffer solutions showed a pl ateau between pH 4 and 7.9. In order to determine the effect of temper ature, the kinetic process at four temperatures (40, 50, 60 and 70 deg rees C) was studied. The apparent heat of activation for ifosfamide de gradation in solution was found to be 118 kJ/mol and by application of the Arrhenius equation the stability at 25 degrees C (k(25)) and the shelf-life (t(90)) has been predicted. The agreement between the thin- layer chromatography (TLC), nuclear magnetic resonance (NMR) and high performance liquid chromatography (HPLC) supports the hypothesis prese nted concerning the reactions involved in the degradation of ifosfamid e solutions.