The metabolism of nicotine-delta 1'(5')-iminium ion, in vivo and in vitro.

Nicotine-delta 1'(5')-iminium ion, either as the diperchlorate or the hydrochloride, is rapidly converted into cotinine by a hepatic cytoplasmic enzyme. Incubations in an atmosphere of nitrogen indicated that the oxygen incorporated into cotinine is derived from water. Following the intraperitoneal administration of nicotine-delta 1'(5')-iminium ion to guinea pigs or rats, cotinine, and nicotine-1'-N-oxide were found in the urine. The results support the idea that nicotine-delta 1'-(5')-iminium ion is an intermediate in the metabolic conversion of nicotine to cotinine.