Berna M, Ackermann B, Ruterbories K, Glass S
Department of Drug Disposition, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
J Chromatogr B Analyt Technol Biomed Life Sci. 2002 Feb 5;767(1):163-8. doi: 10.1016/s0378-4347(01)00548-5.
A liquid chromatographic-tandem mass spectrometric (LC-MS-MS) assay was developed and validated to quantitatively determine olanzapine (OLZ) concentrations in human blood. Liquid-liquid extraction, using n-butanol:cyclohexane (3:47, v/v), was used to isolate OLZ and its internal standard, LY170158, from the biological matrix. Chromatographic resolution of OLZ from endogenous interferences and known metabolites was accomplished with a MetaChem Monochrom HPLC column (4.6 x 150 mm, d(p) 5 microm). Detection occurred using a Perkin-Elmer Sciex API III Plus triple quadrupole mass spectrometer using positive ion APCI and multiple reaction monitoring (MRM). The linear dynamic range was from 5 to 500 ng ml(-1) based on a 0.25-ml aliquot of human blood. The inter-day precision (%RSD) and accuracy (%RE) ranged from 3.65 to 10.64 and from -2.14 to 3.07, respectively. Modifications to an existing assay for the determination of OLZ in human plasma were necessary. A different structural analog was used as the internal standard due to instability observed for the original analog when using human blood as the matrix. A second modification was the addition of the anti-oxidant sodium ascorbate to inhibit degradation of OLZ in human blood, as has been noted by other investigators. Upon fortification of human blood with sodium ascorbate (final concentration, 0.33 mM), OLZ was found to be stable for at least 1 week at -70 degrees C as well as through two freeze-thaw cycles. This assay, which will be used to investigate the distribution of OLZ in human blood, grants insight into the proper sample handling conditions needed to perform valid determinations of OLZ in human blood.
开发并验证了一种液相色谱 - 串联质谱（LC-MS-MS）分析法，用于定量测定人血液中奥氮平（OLZ）的浓度。采用正丁醇：环己烷（3:47，v/v）进行液 - 液萃取，从生物基质中分离出OLZ及其内标LY170158。使用MetaChem Monochrom HPLC柱（4.6 x 150 mm，d(p) 5微米）实现了OLZ与内源性干扰物和已知代谢物的色谱分离。使用Perkin-Elmer Sciex API III Plus三重四极杆质谱仪，采用正离子APCI和多反应监测（MRM）进行检测。基于0.25 ml人血等分试样，线性动态范围为5至500 ng ml(-1)。日间精密度（%RSD）和准确度（%RE）分别为3.65至10.64和 -2.14至3.07。对现有的测定人血浆中OLZ的分析方法进行修改是必要的。由于在以人血为基质时观察到原始内标物不稳定，因此使用了一种不同结构的类似物作为内标。如其他研究者所指出的，第二个修改是添加抗氧化剂抗坏血酸钠以抑制OLZ在人血中的降解。在用抗坏血酸钠强化人血（终浓度为0.33 mM）后，发现OLZ在 -70℃下至少稳定1周，并且经过两个冻融循环仍稳定。该分析方法将用于研究OLZ在人血液中的分布，有助于深入了解在人血液中进行OLZ有效测定所需的适当样品处理条件。
