Pharmacokinetics of Cryptelytrops Purpureomaculatus (mangrove Pit Viper) Venom Following Intravenous and Intramuscular Injections in Rabbits

The pharmacokinetic profiles of Cryptelytrops purpureomaculatus (mangrove pit viper) venom following intravenous and intramuscular injections were investigated in rabbits. The serum levels of the venom were estimated using double-sandwich enzyme-linked immunosorbent assay (ELISA). After intravenous injection (0.2 mg/kg), the serum venom concentration–time course declined in a biexponential manner, consistent with a two-compartment model, with an α-phase half-life of 0.25 h and a β-phase half-life of 27.7 h. The volume of distribution by area was 2.19 L/kg and systemic clearance was 54.7 mL/h/kg. When the venom was injected intramuscularly (0.5 mg/kg), the serum level increased rapidly to reach a peak (500 ng/mL) at about 1 h, which then declined rapidly to a plateau (104–142 ng/mL) at 3–10 h before further gradual decline until the end of the 72-hour study. The terminal half-life (27.0 h), clearance (54.7 mL/h/kg) and volume of distribution (2.13 L/kg) of the venom for intramuscular route were not significantly different from the corresponding values for intravenous route, and the intramuscular bioavailability of the venom was estimated to be 41.6%.