[Pharmacokinetics and the time course of pharmacodynamics of recombinant human erythropoietin (SNB-5001)].

Pharmacokinetics and the time course of pharmacodynamics of recombinant erythropoietin (SNB-5001) were investigated. The plasma concentration of SNB-5001 reached Cmax at 6-7 hr after the subcutaneous injection and gradually decreased. Most of the SNB-5001 in plasma disappeared at 48 hr. Serum erythropoietin activity changed similarly to plasma SNB-5001 concentration. It was indicated that SNB-5001 moves into the plasma and organs having intact bio-activity after its injection. The decrease in serum iron and increase in unsaturated iron binding capacity (UIBC) began at 8 hr after the injection. Both the trough point of serum iron decrease and the peak point of UIBC increase were 24 hr after the injection. Each value recovered to the initial level at 72 hr. Total iron binding capacity did not change. Increase in reticulocytes began at 24 hr and reached the peak at 72-96 hr after the injection of SNB-5001. Reticulocytes count recovered to the initial level at 120 hr. The pharmacodynamics time course after the subcutaneous injection of SNB-5001 was the same as that after the intravenous injection. It was indicated that SNB-5001 reached an effective plasma level at the earlier absorption phase after the subcutaneous injection.