Zileuton

Zileuton is a reversible 5-lipoxygenase (5-LO) inhibitor.{1367} It inhibits 5-LO activity in rat basophilic leukemia-1 (RBL-1) cell supernatant with an IC50 value of 0.5 µM. Zileuton inhibits leukotriene B4 (LTB4; Item No. 20110) production induced by the calcium ionophore A23187 (Item No. 11016) in purified human peripheral blood polymorphonuclear leukocytes (PMNLs; IC50 = 0.6 µM). Zileuton (10 mg/kg, p.o.) prevents antigen challenge-induced increases in specific lung resistance in a sheep model of asthma at 4 to 8 hours post-challenge following administration 2 hours pre-challenge.{42699} Formulations containing zileuton have been used in the prophylaxis and chronic treatment of asthma.