PHARMACOKINETICS AND HEMATOLOGICAL PARAMETERS OF RECOMBINANT-HUMAN-ERYTHROPOIETIN AFTER SUBCUTANEOUS ADMINISTRATIONS IN HORSES

The pharmacokinetics of recombinant human Epo (rHuEpo) were investigat ed after subcutaneous administration to horses. Four horses received a single 30 IU kg(-1) dose of rHuEpo. One horse received three repeated doses of 120 IU kg(-1) at 48 h intervals. Plasma erythropoietin (Epo) was measured by radioimmunoassay. In both cases pharmacokinetic param eters were evaluated using a one-compartment open model and first-orde r input and output rates. The mean values (+/- SD) for elimination hal f-life, CL/F, and V-d/F after a single dose were 12.9 +/- 3.34 h, 11.8 +/- 4.96 Lh(-1), and 233 +/- 126 L, respectively. After repeated dose s, elimination half-life, CL/F, and V-dss/F were 11.3 h, 8.94 L h(-1), and 145.6 L, respectively. No significant differences were observed b etween the haematological parameters after a single 30 IU kg(-1) admin istration compared to baseline values. Multiple and high doses of rHuE po modified red blood cells, haemoglobin, and hematocrit. According to our results, plasma Epo assay can help, during an antidoping control procedure, to support a positive result only up to 72 h after the last rHuEpo