Pharmacokinetics After a Single Subcutaneous Injection of Recombinant Human Thrombopoietin in Human

OBJICTIVE: To study the pharmacokinetics after a single subcutaneous injection of domestic recombinant human thrombopoietin(rhTPO, a product of Sansheng Pharmaceutical Co Ltd) in human. METHODS: Twenty-four healthy volunteers were randomized to 3 groups. The volunteers in three groups received a single injection of rhTPO in a dosage of 0.5 μg.kg~(-1),1.0 μg.kg~(-1) and 2.0 μg.kg~(-1), respectively. Blood samples were collected serially before and after the medication. The rhTPO concentration in serum was determined by ELISA. RESULTS: Following 0.5μg.kg~(-1), 1.0μg.kg~(-1) and 2.0μg.kg~(-1) administration, tpeak occurred at 9.0± l.9 h. 10.8±2.4h and 11.8±5.1h, and Cmax were 0.298±0.081μg.L~(-1), 0.438±0.076μg.L~(-1)and 0.831±0.079μg.L~(-1), respectively. AUC increased proportionally with dose. Slow elimination of the drug was observed with t_(1/2ke)at 46.3 ±6.9 h, 40.2±9.4 h and 38.7±11.9 h in 0.5μg.kg~(-1),1.0μg.g~(-1)and 2.0 μg.kg~(-1) groups, respectively. CONCLUSIONS: When administrated subcutaneously in human within the dosage of 0.5-2.0 μg.kg~(-1), rhTPO behaved as a linear pharmacokinetics and had a prolonged half-life elimination.