Abstract：
According to the ICH S7B guideline, drug candidates are screened for hERG block prior to first-in-human testing to predict the likelihood of delayed repolarization associated with a rare, but life-threatening, ventricular tachyarrhythmia. The new ICH E14 Q&As guideline allows hERG results to be used in later clinical development for decision-making (Q&As 5.1 and 6.1). To pursue this path, the hERG assay should be conducted following the new ICH S7B Q&A 2.1 guideline, which calls for best practice considerations of the recording temperature, voltage protocol, stimulation frequency, recording/data quality, and concentration verification. This study investigated hERG block by cisapride, dofetilide, terfenadine, sotalol, and E-4031 - positive controls commonly used to demonstrate assay sensitivity - using the manual whole cell patch clamp method and an action potential-like voltage protocol presented at 0.2 Hz. Recordings were conducted at room and near physiological temperature. Drug concentrations were measured using samples collected during real patch clamp experiments and satellite experiments. Results showed temperature effects for E-4031, terfenadine, and sotalol, but not cisapride and dofetilide. Cisapride and terfenadine showed substantial concentration losses, largely due to nonspecific binding to the perfusion apparatus. Using concentrations measured from the real and satellite experiments to assess block potencies yielded comparable results, indicating that satellite sample collection may be viable for drugs with nonspecific binding concerns only. In summary, this study provides block potencies for 5 hERG positive controls, and serves as a case study for hERG assays conducted, and results illustrated in accordance with the new ICH E14/S7B Q&As.
摘要：
根据ICHS7B指南，在首次人体测试之前，对候选药物进行hERG阻滞的筛选，以预测与罕见情况相关的延迟复极化的可能性，但危及生命,室性快速性心律失常.新的ICHE14Q&As指南允许hERG结果在以后的临床开发中用于决策（Q&As5.1和6.1）。要走这条路,hERG测定应按照新的ICHS7BQ&A2.1指南进行，这需要记录温度的最佳实践考虑，电压协议，刺激频率,记录/数据质量，和浓度验证。本研究调查了西沙必利对hERG的阻断，多非利特,特非那定,索他洛尔,和E-4031-通常用于证明测定灵敏度的阳性对照-使用手动全细胞膜片钳方法和以0.2Hz呈现的动作电位样电压方案。在室温和接近生理温度下进行记录。使用在真实膜片钳实验和卫星实验期间收集的样品测量药物浓度。结果显示温度对E-4031，特非那定，还有索他洛尔,但不是西沙必利和多非利特。西沙必利和特非那定显示大量浓度损失，主要是由于与灌注器的非特异性结合。使用从真实和卫星实验测得的浓度来评估块的效力，产生了可比的结果，这表明卫星样本采集可能仅适用于具有非特异性结合问题的药物。总之,这项研究为5个hERG阳性对照提供了阻滞效力，并作为hERG测定的案例研究，并根据新的ICHE14/S7BQ&As说明结果。
