R121919 (NBI30775) is a potent small molecule antagonist of the adrenocorticotropic hormone-releasing factor receptor 1 (CRF1), demonstrating antidepressant and anxiolytic activity, and inhibiting the CRF1 receptor, CRF2 receptor, and CRF-binding proteins.

Phenylacetylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. The presence of phenylacetylglycine in urine has been confirmed for dogs rats and mice. However the presence of this compound in human urine is controversial. GC-MS studies have not found this compound while NMR studies claimed to have identified it.

Prototypical δ-opioid receptor agonist that also displays activity at the μ-opioid receptor. Displays antinociceptive activity in vivo.