PHARMACOKINETICS OF ERYTHROPOIETIN FOLLOWING SINGLE-DOSE SUBCUTANEOUSADMINISTRATION IN PRETERM INFANTS

The pharmacokinetics of recombinant human erythropoietin was studied i n 12 very low birth weight preterm infants <32 weeks of gestation afte r subcutaneous administration of 300 IU/kg at a postconceptional age o f 34 (32-37) weeks and a weight of 1,505 (1330-1,740)g (median and ran ge). The administration of recombinant human erythropoietin produced a rapid increase in serum erythropoietin levels with a peak level of 36 2.8 mIU/ml at 8.9 h. The area under the curve was 8,177.5 (4,597.1-15, 453.0) mIU/ml/h, the absorption half-life was 5.5 (1.6-6.6) h, the eli mination half-life was 7.9 (5.6-19.4) h, and the residence time was 19 .6 (5.1-32.6)h (all values reflect median and range). There was no sig nificant correlation between absorption and elimination half-life of e rythropoietin and birth weight, gestational age, sex, and age and weig ht of the infants at the time of administration of erythropoietin. Bas ed on absorption and elimination kinetics, the dosing interval for sub cutaneous administration must not be <48 h.