Comparative Pharmacokinetic Studies of Dehydroemetine and Emetine in Guinea Pigs Using Spectrofluorometric and Radiometric Methods *

Abstract

Summary Natural emetine, synthetic 2-dehydroemetine or the corresponding 14C-labeled compounds were injected intraperitoneally into guinea pigs in the form of the dihydrochloride. The unlabeled drugs were determined spectrofluorometrically, and the 14C-labeled compounds by combustion and liquid scintillation counting. These determinations show that: Dehydroemetine is eliminated more rapidly from each individual organ than is emetine. Dehydroemetine disappears relatively more quickly from the heart than from the liver, whereas the reverse is true of emetine. This may in some way be related to the equal therapeutic activity and lower cardiotoxicity of dehydroemetine compared with emetine. After an intraperitoneal injection of 14C-labeled emetine or dehydroemetine, 95% of the injected radioactivity was recovered in the feces while only 5% appeared in the urine.