title: Pharmacokinetic/pharmacodynamic analysis of neutrophil proliferation induced by recombinant granulocyte colony-stimulating factor (rhG-CSF): comparison between intravenous and subcutaneous administration.
abstract: Pharmacological effect after intravenous (i.v.) or subcutaneous (s.c.) administration of human recombinant granulocyte colony stimulating factor (rhG-CSF) was evaluated by using a physiologically based pharmacokinetic/pharmacodynamic model. The increase of neutrophil counts in blood after s.c. administration of rhG-CSF (0.5-1.0 microgram/kg) was larger than that after i.v. administration of the same dose, while area under the curves of plasma concentration of rhG-CSF after s.c. administration was smaller than that after i.v. administration (Azuma et al., J. Clin. Therap. Med., 5, 1579-1603, 1989). Based on the pharmacokinetic/pharmacodynamic model considering metabolic turnover of neutrophil in vivo, time course of absolute neutrophil counts in blood after either type of rhG-CSF administration to normal healthy volunteers was analyzed. The nonlinear relationship between the concentration of rhG-CSF and in vitro activity for proliferation of neutrophil could be explained by the drug-receptor-effector ternary complex model. These in vivo and in vitro models made it possible to understand the above-mentioned discrepancy of pharmacokinetic/pharmacodynamic behavior between i.v. and s.c. administration of rhG-CSF. Simulation of the neutrophil count-time profiles after repeated i.v. and s.c. dosing of rhG-CSF according to these models showed good agreement with the observed data. In order to obtain the rational dosage regimen of rhG-CSF from pharmacological and economical points of view, a slow constant infusion method may be more useful than rapid infusion.
authors.affiliation: Department of Pharmacy, University of Tokyo Hospital, Faculty of Medicine, University of Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Sugiura
authors.forename: K
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Sawada
authors.forename: T
authors.initials: T
authors.lastname: Iga
mesh_terms: D000279:Administration, Cutaneous; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016179:Granulocyte Colony-Stimulating Factor / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology*; D006801:Humans; D007262:Infusions, Intravenous; D007958:Leukocyte Count / Q000187:drug effects; D051379:Mice; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011994:Recombinant Proteins
chemical_list: D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor