Kinetics of photooxidation of papaverine hydrochloride and its major photooxidation products.
HPCE methodology was modified to be used in kinetic experiments on photooxidation reactions of papaverine hydrochloride 1 and its oxidation products (papaverinol 2 and papaveraldine hydrochloride 3) chloroform solutions exposed to UV254 light in aerobic conditions. On photooxygenation of the above compounds is formed the final degradation product, a brown compound X 4, 2,3,9,10-tetramethoxy-12-oxo-12H-indolo[2,1-a]isoquinolinylim chloride. The rate of 4 formation from the above compounds can be given as 2>3>1>1 HCl. The photooxidation reactions of 1 and 2 proceed with pseudo first-order kinetics and that reaction for 3 follows zero-order kinetics. The most labile compound is 2 whose half-life time is 2.4 times shorter than that one of 1 HCL. The most stable product is 3 whose half-life time is 31-fold longer than of 2. The specific quantum yields are equal 0.28, 0.30 and 0.10 for 1 HCl, 2 and 3, respectively which confirm the above stability pattern of the compounds concerned.
Department of Physical Pharmacy and Pharmacokinetics, Poznań University of Madical Sciences, 6 Swiecickiego Street, 60-781 Poznań, Poland.
Karolina
K
Piotrowska
Tadeusz Władysław
TW
Hermann
Włodzimierz
W
Augustyniak
D002725:Chloroform / Q000737:chemistry*; D004347:Drug Interactions; D007700:Kinetics; D010084:Oxidation-Reduction; D010208:Papaverine / Q000031:analogs & derivatives / Q000737:chemistry*; D010777:Photochemistry / Q000379:methods*; D014665:Vasodilator Agents / Q000737:chemistry*
D014665:Vasodilator Agents; C039657:papaverinol; D002725:Chloroform; D010208:Papaverine