abstract |
The present invention is directed to a compound of the formula (I) wherein for example, a compound below: wherein R1 is CH3, H or Na; and X1-X2-X3 is or its salt or a hydrate thereof. Such a compound is useful as PGD2 antagonist and can be used as a drug for treating diseases in which mast cell dysfunction is involved, for example, systemic mastocytosis and disorders of systemic mast cell activation, and also tracheal contraction, asthma, allergic rhinitis, allergic conjunctivitis, urticaria, injury due to ischemic reperfusion, and as an anti-inflammatory agent. It is particularly useful in the treatment of nasal occlusion. |