Gottas A, Oiestad E L, Boix F, Ripel A, Thaulow C H, Pettersen B S, Vindenes V, Morland J
Dept. of Drug Abuse Research, Div. of Forensic Medicine and Drug Abuse Research, Norwegian Institute of Public Health, Pb 4404 Nydalen, 0403 Oslo, Norway.
J Pharmacol Toxicol Methods. 2012 Jul;66(1):14-21. doi: 10.1016/j.vascn.2012.04.009. Epub 2012 Apr 26.
The pharmacokinetic profile and systemic bioavailability of a substance is often described by blood or total tissue concentrations. For centrally acting drugs, like opioids, the free fraction of active compound in brain extracellular fluid (ECF) is more likely to be correlated to the pharmacodynamic effects than the blood concentrations. Drugs of abuse, like heroin, are often administered intravenously as bolus injections, and the blood concentrations might change rapidly due to metabolism and distribution. The aim of our study was to establish a method to measure the free fraction of heroin and its metabolites in brain ECF, and follow their fast changes in concentration.
Sprague-Dawley rats were injected intravenously with a bolus of heroin. Heroin and its main metabolites 6-monoacetylmorphine, morphine and morphine-3-glucuronide were measured simultaneously. Brain microdialysis was used for sampling and a method for quantification using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed. Deuterated analogues for each analyte were included in the microdialysis perfusion solution as calibrators for recovery estimation.
A highly sensitive UPLC-MS/MS method allowed short sampling intervals, down to one minute, and the simultaneous detection of each analyte and its specific deuterated analogues, making possible the individual recovery calculation for each compound of interest. This method allowed us to determine the pharmacokinetic profiles of heroin and its metabolites in brain-ECF in the same animal after an intravenous injection of heroin.
Our method makes detecting concurrently the rapid changes in concentrations of heroin and its metabolites in brain ECF possible, despite the rapid metabolism of heroin. Recovery was measured specifically for each analyte in the same sample by carefully combining different deuterated analogues. This technique can be applied to pharmacokinetic studies where more than one compound of interest has to be monitored, and to study distribution of prodrugs or drugs with active metabolites.
一种物质的药代动力学特征和全身生物利用度通常通过血液或全组织浓度来描述。对于作用于中枢的药物，如阿片类药物，脑细胞外液（ECF）中活性化合物的游离部分比血液浓度更有可能与药效学效应相关。滥用药物，如海洛因，通常通过静脉推注给药，并且由于代谢和分布，血液浓度可能会迅速变化。我们研究的目的是建立一种方法来测量海洛因及其代谢物在脑ECF中的游离部分，并跟踪其浓度的快速变化。
给Sprague-Dawley大鼠静脉注射一剂海洛因。同时测量海洛因及其主要代谢物6-单乙酰吗啡、吗啡和吗啡-3-葡萄糖醛酸苷。使用脑微透析进行采样，并开发了一种使用超高效液相色谱串联质谱（UPLC-MS/MS）进行定量的方法。每种分析物的氘代类似物作为回收率估计的校准物包含在微透析灌注溶液中。
一种高度灵敏的UPLC-MS/MS方法允许短至一分钟的采样间隔，并能同时检测每种分析物及其特定的氘代类似物，从而能够对每种感兴趣的化合物进行个体回收率计算。该方法使我们能够在静脉注射海洛因后，在同一只动物中确定海洛因及其代谢物在脑ECF中的药代动力学特征。
尽管海洛因代谢迅速，但我们的方法能够同时检测脑ECF中海洛因及其代谢物浓度的快速变化。通过仔细组合不同的氘代类似物，在同一样本中专门测量每种分析物的回收率。该技术可应用于必须监测多种感兴趣化合物的药代动力学研究，以及研究前体药物或具有活性代谢物的药物的分布。
