Distribution of cefdinir, a third generation cephalosporin antibiotic, in serum and pulmonary compartments

The distribution of a new cephalosporin, cefdinir, in serum, epithelial lining fluid (ELF), bronchial mucosa and alveolar macrophages was studied in 17 adults following a single oral dose of 300 or 600 mg of cefdinir; tissue samples being obtained by diagnostic bronchoscopy approximately 4 h after this dose. Mucosal biopsies were taken, alveolar macrophages harvested by lavage, and ELF volume derived from urea concentrations in bronchial lavage fluid and blood. A microbiological assay for cefdinir was performed in serum, bronchial mucosa, ELF and alveolar macrophages. In patients taking 300 mg of cefdinir, the median concentrations of cefdinir were 2.00 mg/L (range 1.40-8.00) in serum, 0.78 mg/L (range 0-1.33) in bronchial mucosa, and 0.29 mg/L (range 0-4.73) in ELF. In patients taking 600 mg, the median concentrations were 4.20 mg/L (range 3.05-6.40) in serum, 1.14 mg/L (range 0-1.92) in bronchial mucosa, and 0.49 mg/L (range 0-0.59) in ELF. Cefdinir did not penetrate macrophages.