The pharmacokinetics of 125I-r-Sak in rats

The purpose is to measure the pharmacokinetic parameters of r-Sak in rats as well as the biodistribution and the excretion of r-Sak in rats. 125I-r-Sak was applied for the purpose. The results showed that the pharmacokinetics of 125I-r-Sak following intravenous injection with two doses (70 μg/kg and 840 μg/kg) in rats was in correspondence with 2-compartment-model. The T1/2(α) were 5.47 +- 2.13 and 8.45 +- 4.50 min and T1/2(β) were 96.15 +- 22.29 and 58.78 +- 32.79 min for the two dose groups. AUC were 0.895 +- 0.455 and 38.36 +- 5.181 μg·min·mL-1. There were no marked differences of T1/2(α) and T1/2(β) between the two dose groups (P > 0.05), but the AUC increased markedly with the dose increasing (P < 0.05). The biodistribution of 125I-r-Sak was wide in rats. Radioactivity wa highest in kidney, followed in order by plasma, liver, lung, spleen, heart and brain. Excretion experiment showed that the sum of the accumulative excretion of the ratio-material plus the enrichment of the ratio-material in thyroid was approximately 80% in 96 h