Priston M J, Sewell G J
FORCE Cancer Research Centre, University of Exeter, UK.
J Pharm Biomed Anal. 1994 Sep;12(9):1153-62. doi: 10.1016/0731-7085(94)00049-2.
Preliminary method development studies on mitozantrone (MTZ) revealed a number of characteristics which were found to be important in the analysis of patient samples for pharmacokinetic studies. MTZ rapidly bound to glass, particularly at low concentrations (< 10 ng ml-1), necessitating the use of silanized glassware or polypropylene tubes for the handling of all solutions containing MTZ. MTZ was also found to react with two commonly-used antioxidants; sodium metabisulphite and EDTA. However, solutions containing MTZ were found to be stabilized by the addition of ascorbic acid (0.5% w/v). In the absence of ascorbic acid, MTZ underwent rapid, biphasic degradation in plasma at 24 and 37 degrees C, with terminal half-lives of approximately 70 h. Ascorbic acid (0.5% 2/v) was found to stabilize plasma samples containing MTZ throughout work-up procedures and during frozen storage. The addition of ascorbic acid to the sample collection vial was also necessary to prevent MTZ degradation in the eluting solvent of the solid-phase extraction system. Another important consideration was the requirement for an equilibration period of > 5 min after the addition of ametantrone (AM) internal standard to plasma samples. This was essential, since the slope of the calibration plot obtained using non-equilibrated plasma was approximately 30% of that obtained for calibration plots using equilibrated plasma, and would result in erroneous determination of MTZ plasma concentrations. The fully developed assay was rapid, precise and sensitive (relative errors at 1 ng ml-1 = 2.3%). MTZ concentrations determined using the LC method described in this report correlated well with an independently developed ELISA technique (r = 0.995, n = 20).
对米托蒽醌（MTZ）进行的初步方法开发研究揭示了许多特性，这些特性在药代动力学研究的患者样本分析中被发现很重要。MTZ能迅速与玻璃结合，尤其是在低浓度（<10 ng/ml）时，因此在处理所有含MTZ的溶液时必须使用硅烷化玻璃器皿或聚丙烯管。还发现MTZ会与两种常用的抗氧化剂发生反应，即焦亚硫酸钠和乙二胺四乙酸（EDTA）。然而，发现通过添加抗坏血酸（0.5% w/v）可使含MTZ的溶液稳定。在没有抗坏血酸的情况下，MTZ在24℃和37℃的血浆中会迅速发生双相降解，终末半衰期约为70小时。发现抗坏血酸（0.5% w/v）在整个后处理过程及冷冻储存期间可稳定含MTZ的血浆样本。在样品收集瓶中添加抗坏血酸对于防止MTZ在固相萃取系统的洗脱溶剂中降解也是必要的。另一个重要的考虑因素是在向血浆样本中添加氨甲蒽醌（AM）内标后需要>5分钟的平衡期。这很关键，因为使用未平衡血浆获得的校准曲线斜率约为使用平衡血浆获得的校准曲线斜率的30%，这会导致MTZ血浆浓度的错误测定。最终开发的测定方法快速、精确且灵敏（1 ng/ml时的相对误差 = 2.3%）。使用本报告中描述的液相色谱法测定的MTZ浓度与独立开发的酶联免疫吸附测定（ELISA）技术相关性良好（r = 0.995，n = 20）。
