Kinetics of hydrolysis of diltiazem hydrochloride in aqueous solutions
Muszalska, I.; Jamszoł, L.; Grześkowiak, D.
Acta Poloniae Pharmaceutica 60(3): 163-168
2003
ISSN/ISBN: 0001-6837 PMID: 14556482 Document Number: 556494
The kinetics of hydrolysis of diltiazem hydrochloride in aqueous solutions at 313, 323, 333 and 353 K over the pH-range 0.4-9.7 has been investigated. The decomposition was followed by the HPLC method. The pH-rate profile was accounted for by the specific acid- and base-catalysed reactions and also by assuming spontaneous or water-catalysed decomposition of both dissociated and undissociated molecules of diltiazem. Various buffer substances were found to exhibit general acid and base catalysis of the degradation. Thermodynamic parameters of the reaction: energy and enthalpy of activation and the frequency factor for the specific rate constants were determined.