Teichomycin A2-5

Background:Teicoplanin is a glycopeptide antibiotic used for the treatment of infections caused by Gram-positive bacteria. There is a good correlation between trough levels and clinical outcome, therefore therapeutic drug monitoring is recommended. Here we present a liquid chromatography-mass spectrometry (LC-MS) method with online extraction based on turbulent flow chromatography for the quantification of the five main components of teicoplanin, A2-1, A2-2, A2-3, A2-4, and A2-5.Methods:After online extraction, analytical chromatography was performed on a Hypersil Gold C8 column under acidic conditions. As mass spectrometer, a Q Exactive hybrid instrument was used. Samples were prepared by adding internal standard and subsequent centrifugation. Patient samples (n=125) that had previously been analyzed using a commercially available immunoassay (QMS teicoplanin) were re-analyzed by LC-MS.Results:The imprecision was <6.9%, inaccuracy between 99.6% and 109%, for both, within- and between-day analysis. The method was shown to be free of matrix effects in the relevant time ranges and was compared to a commercially available immunoassay, QMS® teicoplanin from Thermo Fisher Scientific. The LC-MS assay produced comparable results to the QMS assay, the correlation coefficient was 0.856 (95% confidence interval 0.800-0.896). LC-MS yielded lower concentrations than the immunoassay as could be demonstrated by the bias of -1.16 mg/L (95% confidence interval -1.90-0.43 mg/L) in the Bland-Altman analysis.Conclusions:This specific, automated, LC-MS assay for teicoplanin is suitable for therapeutic drug monitoring.

The interaction between the main components of the new glycopeptide antibiotic teicoplanin, A2-2, A2-3, A2-4, A2-5 and A3-1, and human serum albumin has been studied in vitro by equilibrium dialysis (pH 7.4, 37 degrees C). From Scatchard analysis of the data, the calculated association constants (Ka) were: A2-2, 2.47 X 10(4), A2-3, 2.86 X 10(4), A2-4, 2.95 X 10(4) and A2-5, 3.87 X 10(4) mol.l-1. The number of binding sites per albumin molecule ranged between 1.23 to 1.31. A3-1 had a lower affinity with a Ka of about 5 X 10(3) mol.l-1. Extrapolated to the in vivo situation, the data suggested that about 90-95% of A2 components will be bound to serum albumin, and about 68-72% of A3-1. The in vitro findings were confirmed by a pharmacokinetic study in volunteers given [14C] teicoplanin i.v., in whom the fraction of teicoplanin bound to serum protein ranged between 87.6 and 90.8%.

In this study, a novel and high-throughput liquid chromatography-tandem mass spectrometric (LC-MS-MS) assay was developed and validated for simultaneous determination of two glycopeptides (vancomycin, teicoplanin) and two small molecule compounds (meropenem, voriconazole) in human plasma. Only 50 μL of human plasma is used to quantify these four drugs simultaneously at clinical concentration levels. After a relative simple protein precipitation, the supernatant was then diluted with mobile phase acetonitrile: 0.1% formic acid (5:95, v/v) to avoid solvent effect and reduce the matrix effect. Then, the target compounds were separated on an Agilent Zorbax SB-C18 column (4.6 × 50 mm, 2.7 μm). All the target compounds were detected by positive ion mode. The teicoplanin concentration was determined as the sum of six components (A2-1, A2-2, A2-3, A2-4, A2-5 and A3-1). The method was linear in the concentration range 0.3-30 μg/mL for meropenem; 1-100 μg/mL for teicoplanin and vancomycin; 0.3-10 μg/mL for voriconazole. The lower limit of quantitation (LLOQ) of meropenem and voriconazole were 0.30 μg/mL; and the LLOQ of teicoplanin and vancomycin were 1.0 μg/mL. The intra- and inter-day accuracies were <9.67% and 13.0%, and the precisions were <14.5% at all tested concentrations. The entire analysis time for the four drugs was only 5 min for each sample. The currently developed assay was successfully applied for the therapeutic drug monitoring of 85 patients administered with standard drug treatments, demonstrating its high-throughput clinical usage for the therapeutic drug monitoring.