Kinetics of drug decomposition. Part 37. Kinetics of autoxidation of narcotine in aqueous solutions
Pawelczyk, E.; Zajac, M.; Matlak, B.
Polish Journal of Pharmacology and Pharmacy 28(1): 69-76
1976
ISSN/ISBN: 0301-0244 PMID: 1264860 Document Number: 101829
The overall apparent first-order rate constants for the reaction of autoxidation of Narcotine (NC) - k1 and Cotarnine (CT) - k2 and the rate constants for autoxidation of the protonated (ks) and undissociated (kb) forms have been determined. The kinetic equation for the reaction of autoxidation at constant concentration of NC, CT and the atmospheric oxygen depending on the pH of the reaction medium has been established as: k1 = ks([H+]/([H+]+K'a))+kb(K'a/([H+]+K'a), k2=(ks[H+]+K'a))+kb (K'a/([H+]+K'a) (1+1+1/kt+1K)). The following thermodynamic parameters for the rate constants ks and kb have been calculated: deltaH not equal to, log A and deltaS not equal to.