Olivier Deltombe1, Tom Mertens2, Sunny Eloot3, Alain G Verstraete4. 1. Department of Internal Medicine, Renal Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium. 2. Department of Internal Medicine, Renal Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium. Electronic address: tom.mertens@uzgent.be. 3. Department of Internal Medicine, Renal Division, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium. Electronic address: sunny.eloot@ugent.be. 4. Department of Diagnostic sciences, Ghent University, Corneel Heymanslaan 10, 9000 Ghent, Belgium; Department of Laboratory Medicine, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium. Electronic address: alain.verstraete@ugent.be.
Abstract
OBJECTIVES: The antibiotic teicoplanin, used for the treatment of infections caused by Gram-positive bacteria, is highly bound to plasma proteins (percentage protein binding, %PB, around 90%) and therapeutic plasma levels of total teicoplanin are 10-100 mg/L. Because of the low free concentrations (i.e. <1-10 mg/L), current immunoassays are not able to quantify free teicoplanin concentrations, although they might be more relevant in therapeutic drug monitoring than total concentrations. DESIGN AND METHODS: In this study, an ultra-high performance liquid chromatography - high resolution mass spectrometry (UHPLC-HRMS) method for the quantification of total and free teicoplanin in K2EDTA plasma samples was developed and validated. Furthermore, %PB obtained by ultrafiltration was compared with that obtained by equilibrium dialysis using spiked samples from healthy subjects. Analytes were separated using a phenylhexyl column, gradient mobile phase analysis was used, total run time was 4.5 min and teicoplanin was detected by orbitrap MS. RESULTS: The precision and accuracy were below 15% and within ±15%, respectively and teicoplanin was found to be stable for at least 14 days in plasma at 4 °C. The %PB of teicoplanin in spiked plasma from healthy subjects as obtained by ultrafiltration (94.1 ± 1.3%) was in good agreement with that obtained by equilibrium dialysis (93.6 ± 0.4%), whereas mean %PB of teicoplanin in samples from infected patients who received the antibiotic was 87.7 ± 4.2% (range: 79.6-95.4%). CONCLUSION: A novel highly sensitive UHPLC-HRMS method was developed and validated for the quantification of total and free teicoplanin in human K2EDTA plasma samples. Amongst others, this method is suitable for therapeutic drug monitoring.
OBJECTIVES: The antibiotic teicoplanin, used for the treatment of infections caused by Gram-positive bacteria, is highly bound to plasma proteins (percentage protein binding, %PB, around 90%) and therapeutic plasma levels of total teicoplanin are 10-100 mg/L. Because of the low free concentrations (i.e. <1-10 mg/L), current immunoassays are not able to quantify free teicoplanin concentrations, although they might be more relevant in therapeutic drug monitoring than total concentrations. DESIGN AND METHODS: In this study, an ultra-high performance liquid chromatography - high resolution mass spectrometry (UHPLC-HRMS) method for the quantification of total and free teicoplanin in K2EDTA plasma samples was developed and validated. Furthermore, %PB obtained by ultrafiltration was compared with that obtained by equilibrium dialysis using spiked samples from healthy subjects. Analytes were separated using a phenylhexyl column, gradient mobile phase analysis was used, total run time was 4.5 min and teicoplanin was detected by orbitrap MS. RESULTS: The precision and accuracy were below 15% and within ±15%, respectively and teicoplanin was found to be stable for at least 14 days in plasma at 4 °C. The %PB of teicoplanin in spiked plasma from healthy subjects as obtained by ultrafiltration (94.1 ± 1.3%) was in good agreement with that obtained by equilibrium dialysis (93.6 ± 0.4%), whereas mean %PB of teicoplanin in samples from infectedpatients who received the antibiotic was 87.7 ± 4.2% (range: 79.6-95.4%). CONCLUSION: A novel highly sensitive UHPLC-HRMS method was developed and validated for the quantification of total and free teicoplanin in humanK2EDTA plasma samples. Amongst others, this method is suitable for therapeutic drug monitoring.