Thermal stability of 1,4-dihydropyridine derivatives in solid state.
The effect of temperature and air humidity on the stability of 7 derivatives of 1,4-dihydropyridine (nifedipine, nisoldipine, nitrendipine, nimodipine, nicardipine, felodipine and amlodipine) in solid state has been studied by accelerated testing. Quantitative analysis of the compounds studied was made by UV spectrophotometry, identification of the thermodegradation products and reference to the standard were made by thin layer chromatography (TLC), UV spectra and the reaction with KMnO4. Thermodegradation of the derivatives studied was found not to occur in dry air, whereas at air humidity it occurred according to the first order reaction at a similar rate for all derivatives. The main product of thermodegradation of the derivatives with the nitro substituent was a nitrozoderivative formed as a result of dihydropyridine ring aromatisation accompanied by water molecule elimination.
Marciniec
Barbara
B
Department of Pharmaceutical Chemistry, K. Marcinkowski University of Medical Sciences, 60-780 Poznań, Grunwaldzka 6, Poland.
Ogrodowczyk
Magdalena
M
D017311:Amlodipine / Q000737:chemistry; D002121:Calcium Channel Blockers / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D004095:Dihydropyridines / Q000737:chemistry*; D004355:Drug Stability; D015736:Felodipine / Q000737:chemistry; D006358:Hot Temperature; D009529:Nicardipine / Q000737:chemistry; D009543:Nifedipine / Q000737:chemistry; D009553:Nimodipine / Q000737:chemistry; D015737:Nisoldipine / Q000737:chemistry; D009568:Nitrendipine / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D017311:Amlodipine; D015737:Nisoldipine; D009553:Nimodipine; D009568:Nitrendipine; D009529:Nicardipine; D009543:Nifedipine; D015736:Felodipine