Rokitamycin plasma kinetics and penetration into bronchial secretions in adult bronchitis patients

Abstract Twelve adult patients with exacerbation of chronic bronchitis received five oral doses of rokitamycin 400 mg at 12-hour intervals to study the kinetics of the drug. After the first dose, samples of blood were taken at time 0 (just before drug intake) and at 0.5, 1, 2, 3, 4, and 8 hours after drug intake. After the fifth dose, other blood samples were drawn in nine patients and bronchial secretions were collected from five patients who underwent bronchoscopy for differential diagnostic purposes. Rokitamycin concentrations in plasma and bronchial secretions were assayed by a microbiologic technique with a sensitivity limit of 0.03 μg/ml. After the first dose, the maximum concentration was 0.57 ± 0.08 μg/ml, the time of maximal concentration was 1.17 ± 0.22 hours, the half-life was 3.72 ± 0.82 hours, and the area under the curve was 2.05 ± 0.37 μg · hr/ml. After the fifth dose, the plasma levels were similar to those observed after the first dose, and rokitamycin concentrations in bronchial secretions ranged from 0.15 to 0.50 μg/ml. These results demonstrate that rokitamycin is well absorbed after oral administration in adult patients and that its concentration in bronchial secretions is adequate to treat most lower respiratory tract bacterial infections.