French Deborah, Sujishi Kirk K, Long-Boyle Janel R, Ritchie James C
*Department of Laboratory Medicine; †UCSF Medical Center; and ‡Department of Clinical Pharmacy, University of California-San Francisco; and §Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia.
Ther Drug Monit. 2014 Apr;36(2):169-74. doi: 10.1097/01.ftd.0000443060.22620.cd.
Busulfan is an anti-leukemic, DNA alkylating agent that is used in conditioning regimens for patients undergoing hematopoietic stem cell transplantation. Because of the large intraindividual and interindividual variations seen in busulfan pharmacokinetics, therapeutic drug monitoring is necessary. Currently at the authors' institution, plasma busulfan in adults is measured by gas chromatography-mass spectrometry (GC-MS) at a reference laboratory, whereas pediatric specimens are sent to a different reference laboratory also for GC-MS analysis. As the result turnaround time is not optimal and this practice is of significant cost, a liquid chromatography-tandem mass spectrometry assay to quantify plasma busulfan was developed.
Protein precipitation with D8-busulfan (deuterated internal standard) in acetonitrile was carried out on 50 µL of heparinized plasma. Gradient elution with ammonium acetate, formic acid, water, and methanol at 0.6 mL/min had a 4-minute run time. Multiple reaction monitoring was employed using Q1/Q3 transitions of 264/151 and 264/55 for busulfan and 272/159 and 272/62 for D8-busulfan.
Sample preparation took ∼30 minutes for 6 patient samples. Six calibrators were used (0-2000 ng/mL) with 3 quality controls (means of 12, 356, and 1535 ng/mL). The limits of detection and quantitation were 1 and 6 ng/mL, respectively. Extraction recovery was ∼77% and ion suppression ∼5%. Within-run and between-run precision studies yielded <15% coefficient of variation at the limit of quantitation and <6% coefficient of variation through the rest of the linear range. Method comparisons between this assay and 2 GC-MS assays revealed mean biases of 7% and 1%.
An accurate, rapid, and sensitive liquid chromatography-tandem mass spectrometry assay for quantification of plasma busulfan was developed. This assay reduces current specimen volume requirements, reduces result turnaround time for patients and clinicians, and additionally saves institutional funds.
白消安是一种抗白血病的DNA烷化剂，用于造血干细胞移植患者的预处理方案。由于白消安药代动力学存在较大的个体内和个体间差异，因此需要进行治疗药物监测。目前，在作者所在机构，成人血浆中的白消安由参考实验室通过气相色谱 - 质谱联用（GC - MS）测定，而儿科样本则被送到另一个参考实验室进行GC - MS分析。结果周转时间不理想，且这种做法成本高昂，因此开发了一种液相色谱 - 串联质谱法来定量血浆白消安。
在50μL肝素化血浆中加入氘代白消安（D8 - 白消安，氘代内标）进行蛋白沉淀。以0.6 mL/min的流速用乙酸铵、甲酸、水和甲醇进行梯度洗脱，运行时间为4分钟。采用多反应监测，白消安的Q1/Q3跃迁为264/151和264/55，D8 - 白消安的Q1/Q3跃迁为272/159和272/62。
6份患者样本的样品制备耗时约30分钟。使用了6个校准品（0 - 2000 ng/mL）和3个质量控制品（均值分别为12、356和1535 ng/mL）。检测限和定量限分别为1 ng/mL和6 ng/mL。提取回收率约为77%，离子抑制约为5%。批内和批间精密度研究在定量限处变异系数<15%，在整个线性范围内其余部分变异系数<6%。该方法与2种GC - MS方法的方法比较显示平均偏差分别为7%和1%。
开发了一种准确、快速且灵敏的液相色谱 - 串联质谱法用于定量血浆白消安。该方法减少了当前所需的样本量，缩短了患者和临床医生的结果周转时间，并节省了机构资金。
