Penetration of cefsulodin into bronchial secretions.

The objective of this study was to evaluate the penetration of cefsulodin, a new cephalosporin active against Pseudomonas aeruginosa, into the bronchial secretions. The study was carried out in 28 patients with respiratory infections; 11 patients received a single dose of 1 g i.v. (bolus); 17 patients received multiple doses of 1 g every 8 h for 48 h. Simultaneous samples of blood and bronchial secretions were collected 30 min and 1, 2, 4 and 6 h after injection. Bronchial secretions were obtained from 23 patients by means of fiberoptic bronchoscopy and in 5 tracheostomized patients (with severe respiratory insufficiency) through a tracheostomy cannula. The assays of cefsulodin were performed by means of the microbiological agar diffusion technique. The results of the study showed a noticeable penetration of the drug into the bronchial secretions, with a mean peak reaching 3.1-5.3 micrograms/ml at the 3rd or 4th hour, a slow elimination and residual levels at 6 h ranging between 2.0 and 6.0 micrograms/ml. The rate of penetration was not influenced by the administration of multiple doses of the drug. The ratios between bronchial concentrations and simultaneous serum concentrations ranged between 10 and 30%, corresponding to the usual values found for other cephalosporins. In conclusion, this study provides satisfactory results and confirms the presence of bronchial levels capable of inhibiting P. aeruginosa.