SQ 29,548 is a highly selective TP receptor antagonist which binds to the human recombinant TP receptor with a Ki of 4.1 nM. It inhibits the aggregation of washed human platelets induced by U-46619 with an IC50 of 0.06 μM. It antagonizes U-46619 induced contraction of rat and guinea pig tracheal, arterial, and venous smooth muscles with drug/receptor dissociation constants (KB) in the range of 0.5-1.7 nM. SQ 29,548 also inhibits the contraction of rat vascular smooth muscle induced by 8-iso PGF2α.
