[Metronidazole pharmacokinetics in perilymph, aqueous humor and cerebrospinal fluid]

Since metronidazole is very effective against anaerobic bacteria, we studied its pharmacokinetics in perilymph, cerebrospinal fluid, aqueous humour, and serum. 1, 2, 4, 6, 10 and 16.5 hours after intraperitoneal injection of 200 mg/kg metronidazole to six groups of six guinea pigs each, we determined the drug concentrations by high-pressure liquid chromatography. In the serum, 1, 2 and 16.5 hours after application, drug levels of 194 +/- 22 mg/l, 127 +/- 54 mg/l and 2 +/- 1 mg/l respectively were found. Half-life was 6 hours. Similar high and long-lasting concentrations could be determined in the aqueous humour, cerebrospinal fluid and perilymph. In contrast to our findings with aminoglycoside antibiotics, beta lactam antibiotics and fosfomycin, we could not observe any retention of metronidazole in the perilymph.