A pan-RAR antagonist (Kd = 2, 2, and 3 nM for RARα, β, and γ, respectively); selective for RARs over RXRs (Kd = >10,000 nM for human RXRα, β, and γ receptors); reverses TTNPB-induced changes in cell morphology in ECE16-1 cells; reverses the growth suppressive effects of all-trans-RA, 13-cis-RA, and 9-cis-RA in ECE16-1 cells when used at a 10-fold molar excess; decreases expression of cytokeratin K5-8, 13, 14, 16, 17, and 19 genes, markers of retinoid action in ECE16-1 cells, when co-administered with TTNPB, but not when used alone; induces cleft palate or frontonasal dysplasia and eye malformations in fetuses of pregnant mice following a single oral dose of 1 mg/kg