[Rapid determination of acetaminophen in plasma by LC-MS/MS]

Objective: To establish a method for the rapid determination of acetaminophen (APAP) in human plasma by LC-MS/MS. Methods: The plasma samples were extracted by methanol and acetonitrile (1: 1) and purified directly. C(18) column was used for sample separation. The mobile phase were methanol (5 mmol/L ammonium acetate) and water (5 mmol/L ammonium acetate). Samples were analyzed by LC MS/MS with the electrospray ionization multi reaction monitoring (MRM) mode. Results: The calibration curves of APAP was linear in the concentration range of 0~10 mg/L, the correlation coefficient (r) was greater than 0.999 0. The relative standard deviation within and between batches was less than 10%. The recovery rate were 96.81%~101.7%. The detection limit of the method was 0.1 μg/L and the lower limit of quantification was 0.3 μg/L. Conclusion: This method has strong specificity, high sensitivity and reliable determination results. It is suitable for the rapid analysis of clinical plasma samples.

LC-MS/MS method for determination of r-RGD-hirudin in human plasma and its application in pharmacokinetic study

OBJECTIVE

This study aimed to develop a simple, sensitive, and selective Liquid chromatography with a Mass spectroscopic method for simultaneous quantification of a recombinant bifunctional hirudin (r-RGD-Hirudin, Bifunctional Hirudin, BFH) in human plasma and verify its effectiveness.

METHODS

The analytes and the internal standards from human plasma were extracted using the solid-phase extraction technique. The reconstituted samples were chromatographed on Waters C₁₈ column (BEH 50 × 2.1 mm, 1.7 μm) using a mixture of 0.1% formic acid/acetonitrile (85%/15%, v/v) with gradient elution as the initial mobile phase at a flow rate of 0.3 mL/min.

RESULTS

The effectiveness of the proposed method was verified over the concentration range of 10-2000 ng/mL for r-RGD-Hirudin. A linear calibration curve was obtained. The precision and accuracy of BFH in the intra- and inter-day runs fell within the range of ±15% at LQC, GMQC, MQC and HQC concentrations. The extraction recoveries and matrix effect at two quality control (QC) levels for BFH were confirmed to conform to the relevant requirement.

CONCLUSION

The proposed method was successfully adapted to examine the pharmacokinetics of BFH in 40 Chinese healthy volunteers, respectively.

[The effect of CYP3A5 gene polymorphism on tacrolimus concentration and adverse events in patients undergoing allogeneic hematopoietic stem cell transplantation]

目的

探讨在异基因造血干细胞移植（allo-HSCT）患者中，CYP3A5基因多态性与他克莫司血药浓度及急性移植物抗宿主病（GVHD）间的关系。

方法

回顾性分析2019年7月至2020年2月在中国医学科学院血液病医院接受allo-HSCT的35例中国成人患者。移植前采集骨髓进行CYP3A5基因分型。应用静脉输注他克莫司、短疗程甲氨蝶呤（MTX）±吗替麦考酚酯进行GVHD预防。在他克莫司用药第2天或第3天监测初始血药浓度，随后每周监测2～3次。根据目标血药浓度（10～15 ng/ml）调整药物剂量。

结果

16例携带CYP3A5*3/*3基因的allo-HSCT患者的初始他克莫司血药浓度（9.82 ng/ml对8.53 ng/ml）、初始血药浓度/剂量（C/D）比值（5.72 ng·ml⁻¹·mg⁻¹对4.26 ng·ml⁻¹·mg⁻¹）、allo-HSCT后第一和第二周C/D比值中位数（5.29 ng·ml⁻¹·mg⁻¹对4.61 ng·ml⁻¹·mg⁻¹，5.65 ng·ml⁻¹·mg⁻¹对4.56 ng·ml⁻¹·mg⁻¹）均明显高于19例至少携带一个CYP3A5*1等位基因的患者（P值分别为0.028、0.001、0.037、0.045）。至少携带一个CYP3A5*1等位基因的患者，allo-HSCT后Ⅲ～Ⅳ级急性GVHD的发生率有高于携带CYP3A5*3/*3基因患者的趋势［（26.3±10.1）％对（6.2±6.1）％，P＝0.187］。

结论

CYP3A5基因型导向给药可能有助于allo-HSCT后更快地达到他克莫司目标血药浓度，减少严重急性GVHD的发生，改善移植疗效。

Early effects of Lansoprazole orally disintegrating tablets on intragastric pH in CYP2C19 extensive metabolizers

AIM: To compare rabeprazole (RPZ; 10 mg) with Lansoprazole orally disintegrating tablets (LPZ; 30 mg OD) in terms of antisecretory activity and blood drug concentration after a single dose.

METHODS: Eight H pylori-negative cytochrome P450 (CYP) 2C19 extensive metabolizers were assigned to receive a single oral dose of RPZ 10 mg or LPZ 30 mg OD. Twelve hour intragastric pH monitoring was performed on the day of treatment. Blood samples were also collected after the administration of each drug.

RESULTS: LPZ 30 mg OD induced a significantly earlier rise in blood drug concentration than RPZ 10 mg; consequently, LPZ 30 mg OD induced a significantly earlier rise in median pH in the third and fourth hours of the study.

CONCLUSION: In H pylori-negative CYP2C19 extensive metabolizers, LPZ 30 mg OD induced a significantly faster inhibition of gastric acid secretion than RPZ 10 mg.