Evaluation of the pharmacokinetic parameters of Hemiscorpios lepturus antivenom following intramuscularly injection in rat

Abstract

Hemiscorpios lepturus is one of the most fatal scorpions in Khuzestan province and injection of antivenom intramuscularly is the usual way for treatment of envenomed patients. There is not clear data about pharmacokinetic parameters of this treatment. After radiolabelling of 300µl of scorpion antivenom, using chloramine-T method, sephadex G50 column was used to extract the iodinated venom from free iodine. The radiolabelled antiveon (0.2 ml) was injected into 18 Wister rats (average weight 200g). Three rats were sacrificed at each of the following time points: 10, 40, 60, 120, 210 and 360 minutes. Blood samples were collected from the right atrium. Radioactivity was measured by gamma counter within one minute of blood collection and the amount of venom at each time point was calculated in relation to the radioactivity of stock control value. The results were following: Tmax Minute 120 Cmax Unit/ml 7.2 AUClast min×{unit/ml} 2184 HL_lambd_z min 308 Vz_F_obsereved ml 10.2 Cl_F_observed ml/min 0.02 F: is bioavailability Regarding to long time of Tmax and also the amount of Cmax, intramuscular injection of scorpion antivenom is not the best way for immediate treatment of envenomed patients and also by way of intravenous injection the amount of F must be estimated by (Mean AUCSC / Mean AUCIV) for actual estimation of clearance and also volume of distribution of scorpion antivenom. It should be noted that degradation of the toxins might occur in vivo and that degraded toxins could still be quantified by radioactivity, so by decreasing the time interval of our blood samples and also using of another precise methods like ELISA the actual results will be clarified.