Pharmacokinetics of Recombinant GM-CSF/IL-3 Fusion Protein in Rats

The pharmacokinetics of GM-CSF/IL-3 fusion protein was studied.An isotopic tracer method coupling with HPLC was established to determine the MX fusion protein in rat serum.Pharmacokinetics parameters of MX in rats were obtained at three-doses level by sc injection and one level by iv.The results showed that the biological half-life of MX at three-doses level by sc injection is(15.4±2.0)h,(16.1±1.8),(13.2±2.2)()h;The AUC is(588±120),(286±47),(142±20) g/(L·h) and the C_(max)is(31.2±8.3),(14.8±1.2),(8.3±1.4)μg/L.The C_(max) and AUC of MX after sc injection were proportional to dose,which suggested that MX had the pharmacokinetics linearity over the dose range from 35μg/kg to 140μg/kg.The bioavailability of MX was approximately 35.6% at the dose of 70μg/kg.