Purity >98% by HPLC. Potent corticotropin-releasing factor (CRF) receptor antagonist (Ki values are 2, 1.5 and 1 nM at CRF1, CRF2a and CRF2b respectively). Displays inhibition of ACTH secretion in vitro. If injected into the CSF at low doses (1-10 μg), it has an antagonistic action against CRF and stress-related alterations of gastrointestinal motor function, without an intrinsic effect in these in vivo systems.