Abstract
KRN321, darbepoetin alfa, is a hyperglycosylated analog of recombinant human erythropoietin (rHuEPO, epoetin alfa). We carried out the validation study by using a commercially available ELISA assay kit to establish the ELISA quantitation method for KRN321 in rat serum for the implementation of the pharmacokinetic studies with a lower limit of quantitation at 100 pg/mL and quantitation range from 100 to 4,000 pg/mL. We also established the in vitro bioassay method as an index of biological activity using UT‐7/Epo, derived from a human leukemia cell line with a lower limit of quantitation, at 10 ng/mL. Furthermore, good correlation was observed between the two methods; it indicated that KRN321 concentration determined by the ELISA maintained biological activity.
Acknowledgments
The authors wish to thank Dr. Takenori Natori from the Pharmaceutical Development Laboratories, Pharmaceutical Division, Kirin brewery Co., Ltd. for continuous and valuable support.