Teicoplanin metabolism in rats.

This study was done to see whether teicoplanin undergoes metabolic transformation in rats. Sprague-Dawley rats were given 7.6 mg of [14C]teicoplanin (904 U/mg, 7.6 muCi/mg) per kg intravenously; 73.2 +/- 4.0% of the administered radioactivity and 59.1 +/- 4.8% of the administered microbiological activity were recovered in the 24-h urine samples. The difference between these two values was due to adsorption of teicoplanin to the urinary sediment, making some of the antibiotic not available for microbiological determination. In fact, after a sample or urine was filtered through an Acrodisc (0.45 micron pore size), radiochemical and microbiological data for the filtrate were very similar. Possible metabolites were looked for by high-performance liquid chromatographic analysis of the teicoplanin complex composition in the urine samples, with both UV and radioactivity detection. The quantitation, based on the 14C percentage in each peak, showed that no more than 3 to 5% of the [14C]teicoplanin underwent metabolic and/or chemical transformation.