Institute of Pharmacy, University of Regensburg, Regensburg, Germany.
Department of Anaesthesiology, University Hospital Regensburg, Regensburg, Germany.
Bioanalysis. 2024;16(14):747-756. doi: 10.1080/17576180.2024.2365526. Epub 2024 Jul 23.
To assess the impact of experimental conditions on free serum concentrations as determined by ultrafiltration and HPLC-DAD analysis in a wide range of antibiotics. Relative centrifugation force (RCF), temperature, pH and buffer were varied and the results compared with the standard protocol (phosphate buffer pH 7.4, 37°C, 1000 × g). Generally, at 10,000 × g the unbound fraction () decreased with increasing molecular weight, and was lower at 22°C. In unbuffered serum, the of flucloxacillin or valproic acid was increased, that of basic or amphoteric drugs considerably decreased. Comparable results were obtained using phosphate or HEPES buffer except for drugs which form metal chelate complexes. Maintaining a physiological pH is more important than strictly maintaining body temperature.
评估超滤和 HPLC-DAD 分析在广泛的抗生素中测定游离血清浓度时实验条件的影响。改变相对离心力（RCF）、温度、pH 值和缓冲液，并将结果与标准方案（磷酸盐缓冲液 pH 7.4，37°C，1000×g）进行比较。通常，在 10,000×g 时，未结合分数（）随着分子量的增加而减少，在 22°C 时更低。在未缓冲的血清中，氟氯西林或丙戊酸的增加，碱性或两性药物的则大大减少。除了形成金属螯合络合物的药物外，使用磷酸盐或 HEPES 缓冲液可获得类似的结果。保持生理 pH 值比严格保持体温更为重要。
