Finally, both analogs were also evaluated for ability to bind to the hERG potassium channel to assess for potential cardiac liability. Analog 20 displayed 0% inhibition of [ 3 H]-astemizole binding at a dose of 10 µM while 38 and 39 exhibited 6% and 11% inhibition at the same dose (Table ). No molecule was determined to be a significant hERG binder.