Penetration of ciprofloxacin in bronchial secretions after intravenous administration

Ciprofloxacin concentrations in serum and in bronchial secretions were studied after single and multiple intravenous administrations for two days in ten patients. The dose given was either 0.75 or 1.5 mg/kg. With the lower dose, the peak concentrations in the bronchial secretions were (mean +/- S.D.) 0.40 +/- 0.29 mg/l after the first injection and 0.35 +/- 0.25 mg/l after the fourth injection. With the higher dose, the corresponding mean peak bronchial concentrations were 0.84 +/- 0.58 and 1.16 +/- 0.86 mg/l respectively. The half-lives of the drug in bronchial secretions ranged from 2.13 to 3.72 h. The penetration of ciprofloxacin into bronchial secretions was excellent as demonstrated by the high ratios of the areas under the concentration curves obtained in the serum and in bronchial secretions which ranged from 0.79 to 1.11.