MK-591, Free acid

MK-0591 is a potent and specific 5-Lipoxygenase-activating protein (FLAP) inhibitor with an IC₅₀ of 1.6 nM in FLAP binding assay; it displays no inhibitory effect on 15-lipoxygenase and platelet 12-lipoxygenase and cyclooxygenase in human PMNLs; potently inhibits leukotriene (LT) biosynthesis in intact human and elicited rat PMNLs with IC₅₀ of 3.1 and 6.1 nM, respectively.