A Novel In Vivo Receptor Occupancy Methodology for the Glucocorticoid Receptor: Toward An Improved Understanding of Lung Pharmacokinetic/Pharmacodynamic Relationships
A Novel In Vivo Receptor Occupancy Methodology for the Glucocorticoid Receptor: Toward An Improved Understanding of Lung Pharmacokinetic/Pharmacodynamic Relationships
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DOI：
10.1124/jpet.114.221226
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发表时间：
2015-05-01
影响因子：
3.5
通讯作者：
Friden, Markus
中科院分区：
文献类型：
--
作者：
Boger, Elin;Ewing, Par;Friden, Markus
研究吸入药物的药代动力学/药效学（PK/PD）关系具有挑战性，因为测量组织暴露和肺部靶点结合的可能性有限。本研究的目的是开发一种方法，用于测量大鼠体内糖皮质激素受体（GR）的受体结合率，以进行更多信息的吸入PK/PD研究。从AstraZeneca的GR结合剂的化学文库中，化合物1 [N-（2-氨基-2-氧代-乙基）-3-[5-[（1 R，2S）-2-（2，2-二氟丙酰基氨基）-1-（2，3-二氢-1，4-苯并二氧杂环己烷-6-基）丙氧基]吲唑-1-基]-N-甲基-苯甲酰胺]被鉴定为具有可用作体外GR示踪剂的性质。当以适当剂量（30 nmol/kg）给予大鼠时，使用液相色谱-串联质谱生物分析，化合物1在体内肺和脾中充当示踪剂。该方法成功地用于显示丙酸氟替卡松（20、150和750 nmol/kg）静脉给药后1.5小时测量的剂量-受体结合率关系，以及表征90 nmol/kg静脉给药后受体结合率的时间曲线。估计50%结合率的剂量为47 nmol/kg。该方法是新颖的，在测量占用严格在体内和使用未标记的示踪剂。该特征赋予了关键优势，包括占用估计不受死后发生的药物颗粒溶解或结合/解离的影响。此外，示踪剂可以被标记用于正电子发射断层摄影成像，从而使得能够在人类中进行占用估计，作为靶标接合的可翻译生物标志物。
Investigation of pharmacokinetic/pharmacodynamic (PK/PD) relationships for inhaled drugs is challenging because of the limited possibilities of measuring tissue exposure and target engagement in the lung. The aim of this study was to develop a methodology for measuring receptor occupancy in vivo in the rat for the glucocorticoid receptor (GR) to allow more informative inhalation PK/PD studies. From AstraZeneca's chemical library of GR binders, compound 1 [N-(2-amino-2-oxo-ethyl)-3-[5-[(1R,2S)-2-(2,2-difluoropropanoylamino)-1-(2,3-dihydro-1,4-benzodioxin-6-yl) propoxy] indazol-1-yl]-N-methyl-benzamide] was identified to have properties that are useful as a tracer for GR in vitro. When given at an appropriate dose (30 nmol/kg) to rats, compound 1 functioned as a tracer in the lung and spleen in vivo using liquid chromatography-tandem mass spectrometry bioanalysis. The methodology was successfully used to show the dose-receptor occupancy relationship measured at 1.5 hours after intravenous administration of fluticasone propionate (20, 150, and 750 nmol/kg) as well as to characterize the time profile for receptor occupancy after a dose of 90 nmol/kg i.v. The dose giving 50% occupancy was estimated as 47 nmol/kg. The methodology is novel in terms of measuring occupancy strictly in vivo and by using an unlabeled tracer. This feature confers key advantages, including occupancy estimation not being influenced by drug particle dissolution or binding/dissociation taking place postmortem. In addition, the tracer may be labeled for use in positron emission tomography imaging, thus enabling occupancy estimation in humans as a translatable biomarker of target engagement.