Improved quantitative determination of total and unbound concentrations of six teicoplanin components in human plasma by high performance liquid chromatography.

Total and unbound concentrations of six teicoplanin components in human plasma were determined by high-performance liquid chromatography with a coextractive cleanup technique. Unbound concentrations of teicoplanin components were estimated after ultrafiltration of plasma. For determination of each component in plasma, plasma was deproteinized with acetonitrile and the supernatant was shaken for 60 s with chloroform under acidic conditions. The recoveries of A3-1, A2-1, A2-2, A2-3, A2-4 and A2-5 were greater than 88%. The within-day and between-day coefficients of variation were 1.3-8.8% and 2.8-11.9%, respectively. The limits of detection in ultrafiltered plasma for each component were 0.82, 2.87, 4.23, 3.36, 7.33 and 4.93 nM, respectively. A good correlation was observed between the FPIA and HPLC methods when total concentrations of each teicoplanin component in patient plasma were determined. The analytical methods established in this study are suitable for determining the total and unbound concentrations of six components of teicoplanin in human plasma and for studying the pharmacokinetics of teicoplanin components in patients.