Josamycin pulmonary penetration determined by broncho-alveolar lavage in man.

Macrolide antibiotics are concentrated by phagocytic cells in vitro. We studied the in-vivo uptake of josamycin by alveolar macrophages recovered by broncho alveolar lavage performed in patients 3 h after ingestion of 1 g of the drug. Simultaneous determination of the antibiotic levels was performed on the BAL supernatant and the serum and the results compared to those obtained by incubating alveolar macrophages and blood polymorphonuclears at 2 and 8 mg/l. Josamycin concentration was measured using a high pressure liquid chromatography method. Results show that intracellular josamycin levels in vivo are similar to those observed in vitro. Accumulation of the drug also occurs in BAL fluid (reaching about a 100-fold the serum concentration). Pulmonary and serum levels are significantly correlated.