Penetration of erythromycin stearate into maxillary sinus mucosa and secretion in chronic maxillary sinusitis

The penetration of oral erythromycin stearate (Abboticin), administered in a dosage of 500 mg three times a day, into the maxillary sinus mucosa and secretion was studied in 15 patients (22 sinuses) operated on for chronic maxillary sinusitis. The average concentration in serum was 2.3 microgram/ml, 1.2 microgram/ml in secretion, and 1.8 microgram/ml in mucosa. These concentrations are highly effective against diplococci and most aerobic and anaerobic streptococci (MIC value 0.06 microgram/ml) but not against Haemophilus influenzae (MIC value for 80% of 2 microgram/ml).