Potent hematopoietic prostaglandin D synthase (H-PGDS) inhibitor (IC50 = 83 nM). Inhibits PGD2 production and late phase nasal blockage in an animal model of allergic rhinitis. Exhibits negligible effects on COX-1, COX-2, 5-LOX, LTC4 synthase, TXA2 synthase and microsomal prostaglandin E2 synthase. Purity 98%. MW (observed): 487.55