Single and multiple dose pharmacokinetics of ciprofloxacin

Penetration of ciprofloxacin into nasal secretion was studied in 20 healty volunteers to whom 500 mg oral ciprofloxacin was administered twice daily for eight days. Nasal secretion and blood samples were collected following the 1st and 15th dose and samples assayed microbiologically. Absolute concentrations of ciprofloxacin in serum and nasal secretion as well as kinetic parameters indicate that repeated administration did not result in significantly increased serum or nasal secretions levels although there was a tendency towards slight drug accumulation. The rate of penetration of ciprofloxacin into nasal secretion was 73% following the first oral dose and 90% following the 15th oral dose.