PHARMACOKINETICS OF CYTOTOXIN FROM CHINESE COBRA (NAJA-NAJA-ATRA) VENOM

The pharmacokinetics of cytotoxin from Chinese cobra (Naja naja atra) venom was studied in rabbits after i.v. and i.m. injection of 0.2 and 0.5 mg.kg-1, respectively. The plasma levels of the cytotoxin were analysed by a biotin-avidin enzyme-linked immunosorbent assay. The plasma concentration-time course after i.v. administration fitted a two-compartment open model. The half-life (mean+/-S.D.) of the alpha-phase was 5.8+/-0.6 min and that of the beta-phase 3.5+/-0.2 hr. Apparent volume of distribution was 1.7+/-0.3 litres.kg-1, and clearance was 5.6+/-1.4 ml.min-1. A rapid absorption was observed after i.m. injection with peak plasma level of 260+/-90 ng.ml-1 reached within 13.6+/-2.4 min. The absorption rate constant was 0.16+/-0.03 ml-1. The area under the plasma concentration-time curve was 33+/-15 mug.min.ml-1.