A-987306

A-987306 is a potent and oral bioavailable histamine H₄ antagonist, with K_is of 3.4 nM and 5.8 nM for rat H₄, and human H₄. A-987306 shows anti-inflammatory activity in mice peritonitis model^[1]. In Vitro: A-987306 has potent functional antagonism in vitro at human, rat, and mouse H₄ receptors in cell-based FLIPR assays^[1].
A-987306 is 620-fold, >1600-fold, and 162-fold selective for the human H₄R over the human H₁, H₂ , and H₃ receptors in cell-based Ca²⁺-flux functional assay (FLIPR)^[1].
A-987306 shows lower selectivity for H₄R in the rat (only 4-fold selective for the rat H₄R over the rat H₃R) in FLIPR^[1].
In Vivo: A-987306 (98.23 μg/kg-9.82 mg/kg; i.p.) is found to reduce scratching induced by the histamine H₄ agonist clobenpropit (HY-101198)^[1].
A-987306 (10 mg/kg; p.o.) has a moderate fractional oral bioavailability (F_po/iv=26%) with a half-life of 3.7 h and a C_max of 0.30 µM at a T_max of 1.5 h after dosing^[1].