Patent ID: 7820453

Claim:
An assay for screening test compounds, comprising: a) incubating a source containing a HERG polypeptide comprising SEQ ID NO: 2 with: i) radiolabeled astemizole of formula (III) b) incubating the source containing a HERG polypeptide comprising SEQ ID NO: 2 and the radiolabeled astemizole of formula III with: ii) the test compound; c) measuring the amount of radiolabeled astemizole bound to the HERG polypeptide in step a); d) measuring the amount of radiolabeled astemizole bound to the HERG polypeptide in step b); e) comparing the amount of radiolabeled astemizole bound to the HERG polypeptide measured in step a) with the amount of radiolabeled astemizole bound to the HERG polypeptide measured in step b); wherein a decrease in the amount of radiolabeled astemizole bound as a result of said test compound indicates that said test compound may induce cardiotoxicity or cardiac arrythmia in a subject.