title: Kinetics of hydrolysis of diltiazem hydrochloride in aqueous solutions.
abstract: 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.
authors.affiliation: Department of Pharmaceutical Chemistry, Karol Marcinkowski, University of Medical Sciences, 6 Grunwaldzka Str., 60-780 Poznań, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Muszalska
authors.forename: Leszek
authors.initials: L
authors.lastname: Jamszoł
authors.forename: Dariusz
authors.initials: D
authors.lastname: Grześkowiak
mesh_terms: D002021:Buffers; D002121:Calcium Channel Blockers / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004110:Diltiazem / Q000737:chemistry*; D006868:Hydrolysis; D007202:Indicators and Reagents; D007700:Kinetics; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D002021:Buffers; D002121:Calcium Channel Blockers; D007202:Indicators and Reagents; D012996:Solutions; D004110:Diltiazem