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Determination of free clindamycin, flucloxacillin or tedizolid in plasma: Pay attention to physiological conditions when using ultrafiltration
Author(s) -
Dorn Christoph,
Schießer Selina,
Wulkersdorfer Beatrix,
Hitzenbichler Florian,
Kees Martin G.,
Zeitlinger Markus
Publication year - 2020
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.4820
Subject(s) - chemistry , flucloxacillin , chromatography , ultrafiltration (renal) , pharmacokinetics , therapeutic drug monitoring , protein precipitation , clindamycin , extraction (chemistry) , pharmacology , antibiotics , staphylococcus aureus , biochemistry , medicine , biology , bacteria , genetics
Pharmacokinetic/pharmacodynamic indices of anti‐infective drugs should be referenced to free drug concentrations. In the present study, clindamycin, flucloxacillin and tedizolid have been determined in human plasma by HPLC–UV. The drugs were separated isocratically within 3–6 min on a C 18 column using mixtures of phosphate buffer–acetonitrile of pH 7.1–7.2. Sample treatment for the determination of total drug concentrations in plasma included extraction/back‐extraction (clindamycin) or protein precipitation (flucloxacillin, tedizolid). The free drug concentrations were determined after ultrafiltration. An ultrafiltration device with a membrane consisting of regenerated cellulose proved to be suitable for all drugs. Maintaining a physiological pH was crucial for clindamycin, whereas maintaining body temperature was essential for tedizolid. The methods were applied to the analysis of total and free drug concentrations in clinical samples and were sufficiently sensitive for pharmacokinetic studies and therapeutic drug monitoring.