Concentrations of flurithromycin in serum and tonsils

The concentrations of flurithromycin in serum and palatine tonsils of eleven adult male patients undergoing tonsillectomy were determined. Each patient received 500 mg t.i.d., in all ten doses, before tonsillectomy. Flurithromycin concentrations were measured by a microbiological method. Mean serum levels (+/- SE) were 0.72 microgram/ml (+/- 0.19) after 8 h from the 9th dose and 0.67 microgram/ml (+/- 0.13) after 4 h from the 10th dose. Average concentrations (+/- SE) in tonsils were: 1.43 +/- 0.20 microgram/g (right) and 1.32 +/- 0.21 (left) 4 h after the last administration. Therefore, the mean tissue/serum ratio was about 2:1. These results indicate a good diffusion of flurithromycin from serum to tonsillar tissue.