Pharmacokinetic study and metabolite identification of Colistin sulfate in rats

Table 1：Drug concentration of Colistin in plasma and tissue of rats.After intravenous injection of colistin (6 mg/kg), distribution peaked in the kidney at (125.8 ± 22.55) μg/mL, indicating it as a primary biotransformation site. Liver and lung levels exceeded plasma, while heart and spleen levels were low. No colistin was detected in the intestine.
Table 2：Residual percentage of Colistin at different time points in the in vitro incubation model (Mean ± SD，n=3).The t1/2 and CLint values in liver, kidney, and lung models varied, with lung showing the slowest elimination. Microsomes exhibited slower elimination than tissue homogenates, and kidney and liver microsomes had similar t1/2 and CLint values despite differences in degradation.