Bodnar-Broniarczyk Magdalena, Warzyszyńska Karola, Czerwińska Katarzyna, Marszałek Dorota, Dziewa Natalia, Kosieradzki Maciej, Pawiński Tomasz
Department of Drug Chemistry, Medical University of Warsaw, 02-097 Warsaw, Poland.
Department of General and Transplantation Surgery, Medical University of Warsaw, 02-014 Warsaw, Poland.
Pharmaceutics. 2022 Mar 12;14(3):632. doi: 10.3390/pharmaceutics14030632.
(1) Background: Only unbound tacrolimus particles are considered to be active and capable of crossing cellular membranes. Thus, the free-drug concentration might be better associated with clinical effects than the total drug concentration used for dosage adjustment. We propose a new, fully validated online liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for unbound tacrolimus concentration measurement. (2) Methods: The determination of the unbound tacrolimus concentration in plasma ultrafiltrate was performed with the Nexera LC system with LCMS-8050 triple quadrupole MS using ascomycin as an internal standard. Chromatographic separation was made using a HypurityC18 analytical column. MS/MS with electrospray ionization and positive-ion multiple-reaction monitoring was used. The unbound tacrolimus level was determined in 36 patients after solid organ transplantation ( = 140). (3) Results: A lower limit of quantification 0.1 pg/mL was achieved, and the assay was linear between 0.1 and 20 pg/mL (R = 0.991). No carry-over was detected. The within-run and between-run accuracies ranged between 97.8-109.7% and 98.3-107.1%, while the greatest imprecision was 10.6% and 10.7%, respectively. Free tacrolimus in patients' plasma ultrafiltrate varied between 0.06 and 18.25 pg/mL (median: 0.98 pg/mL). (4) Conclusions: The proposed method can be easily implemented. The significance of the unbound tacrolimus concentration needs to be investigated. This may facilitate the individualization and optimization of immunosuppressive treatment.
(1) 背景：只有游离的他克莫司颗粒被认为具有活性且能够穿过细胞膜。因此，游离药物浓度可能比用于剂量调整的总药物浓度与临床效果的关联更好。我们提出了一种全新的、经过全面验证的在线液相色谱 - 串联质谱法（LC-MS/MS）用于测定游离他克莫司浓度。(2) 方法：使用配备LCMS - 8050三重四极杆质谱仪的Nexera LC系统，以子囊霉素作为内标，测定血浆超滤液中游离他克莫司的浓度。采用HypurityC18分析柱进行色谱分离。使用电喷雾电离和正离子多反应监测的串联质谱法。对36例实体器官移植患者（ = 140）测定了游离他克莫司水平。(3) 结果：实现了0.1 pg/mL的定量下限，该测定法在0.1至20 pg/mL之间呈线性（R = 0.991）。未检测到残留。批内和批间准确度分别在97.8 - 109.7%和98.3 - 107.1%之间，而最大不精密度分别为10.6%和10.7%。患者血浆超滤液中的游离他克莫司在0.06至18.25 pg/mL之间变化（中位数：0.98 pg/mL）。(4) 结论：所提出的方法易于实施。游离他克莫司浓度的意义需要进一步研究。这可能有助于免疫抑制治疗的个体化和优化。
