Investigation of lacidipine, a new 1,4-dihydropyridine antihypertensive agent and three chemically related compounds by means of chemical ionization, mass spectrometry and collision-induced dissociation

✍ Scribed by M. Harridan; M. Scandola; D. Franchi; G. Gaviraghi; G. Tarzia

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 813 KB
• Volume: 27
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/oms.1210270315

✦ Synopsis

Chemical ionization of two 1,4dihydropyridines, lacidipine and its Z-isomer, and their corresponding pyridines in three different reagent gases and the collision-induced dissociation (CID) of their respective mass-selected protonated molecular ions in the collision energy range 1&200 eV were performed on a multiple quadruple instrument. The weakness of the Brensted acid NH,' as a protonating agent is clearly manifested in one of the ammonia positive-ion chemical ionization (CI') mass spectra which displays the addition ion, [ M + NH,] +, as the favoured reaction channel. The stereochemistry of the precursor molecules, the exothermicity of the protonation process and the threshold of certain dissociation channels as a function of the collision energy are among the arguments invoked to explain some of the observed differences between the CI' mass spectra and the CID data of the different isomers investigated. In an attempt to present a more comprehensive study, some high-performance liquid chromatographic retention times and resolutions are also given.