MK-0591, an analog of MK-886 is a potent and orally active leukotriene biosynthesis inhibitor with an IC50 value of 600 ng/ml. MK-0591(250 mg) nearly completely inhibited systemic leukotriene synthesis (>90%) in whole blood or in patients with active disease, and induced LTB4 synthesis in the target tissue of inflammation. [1] MK-0591 plays as a potential agent for the treatment of asthma and inflammatory bowel disease. MK-0591 specific interacted with 5-lipoxygenase, a membrane protein activating protein FLAP, which is essential for LT synthesis in inflammatory cells. [3] MK-0591 inhibited 96% production of LTB4 in whole blood and 91% that from BAL cells. By contrast, MK-0591 had no effect on airway hyper-responsiveness, ozone-induced bronchoconstriction, or influx of neutrophils into BAL. [4] References: 1.Hillingsø J, Kjeldsen J, Laursen LS et al. Blockade of leukotriene production by a single oral dose of MK-0591 in active ulcerative colitis. Clin Pharmacol Ther. 1995 Mar;57(3):335-41. 2.Prasit P, Belley M, Blouin M et al. A new class of leukotriene biosynthesis inhibitor: the development of MK-0591. J Lipid Mediat. 1993 Mar-Apr;6(1-3):239-44. 3.Stevens WH, Lane CG, Woolley MJ et al. Effect of FLAP antagonist MK-0591 on leukotriene production and ozone-induced airway responses in dogs. J Appl Physiol (1985). 1994 Apr;76(4):1583-8.
