Pharmacokinetics and distribution of fraction Ⅲ isolated from Naja naja atra venom / 中国病理生理杂志

ABSTRACT

AIM: To investigate the distribution in mice and pharmacokinetics in rabbits of fraction Ⅲ isolated from Naja naja atra venom. METHODS: Fraction Ⅲ was labelled with [~(125)Ⅰ] by chloramine-T method. The drug concentration in blood was determined by a radionuclide tracing kinetic methods. The distribution of [~(125)Ⅰ]-fraction Ⅲ in mice was determined based on the ratio of the relative incorporation of radioactivity in tissues to that in blood. RESULTS: In two and four hours after intravenous injection of fraction Ⅲ in mice, the organs in which the ratio of the radioactivity incorporation was bigger than 1 were liver, kidney, lung, heart and muscle, whth the maximun in kidney. After intravenous injection of fraction Ⅲ, with dosages of 75, 150 and 300 ?g/kg, respectively, the T_(1/2)?, T_(1/2)? and T_(1/2)? were 39.6-42.5 min, 16.8-17.3 h and 21.7-22.1 h, respectively. There was no significant difference between the different dosages. CONCLUSION: Fraction Ⅲ was mostly found in kidney, followed by liver and lung after intravenous administration in mice. The pharmacokinetics is in accordance with the feature of three atrioventricular modle. The AUC is in direct proportion to the dosage. It suggests that the distribution and clearance of the drug is a grade 1 linear kinetic process. [