Absorption and blood leukocyte dynamics of recombinant human granulocyte colony-stimulating factor (rhG-CSF) from intranasally administered preparations containing rhG-CSF and cyclodextrins in rabbits☆

Abstract The absorption of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and blood leukocyte dynamics following intranasal (i.n.) administration of aqueous preparations containing rhG-CSF with or without cyclodextrins (CyDs) were investigated in conscious rabbits by measuring the serum G-CSF concentration and the total number of leukocytes in peripheral blood. Serum G-CSF concentration was rapidly increased by coadministration of rhG-CSF and CyD, particularly, α and β types. The total number of leukocytes in blood peripheral blood also increased (the maximum of level of approx./μl was attained 24 h after administration) and exceeded physiological levels (5200–12000/μl) in rabbits. The increase in the number of leukocytes was observed between approx. 8 and 48 h after i.n. administration. These results suggest that rhG-CSF is efficiently absorbed through the nasal mucosa. It may be concluded that the development of a rhG-CSF delivery system could be achieved in the form of the nasal administration of rhG-CSF with CyDs.