Zileuton sodium is an inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes(LTB4, LTC4, LTD4 and LTE4) formation with an IC50 value of 0.5μM.
Zileuton sodium has been reported to concentration-dependently inhibit the 5-lipoxygenase activity with an IC50 value of 0.5μM in RBL-1cell lysate. In addition, Zileuton sodium has been found to be a potent inhibitor of LTB formation with an IC50 value of 0.6μM. Furthermore, stimulated with A23187, Zileuton sodium has shown a dose-dependent reduction in LTB4 and 5-HETE generation in rat leukocyte with IC50 values of 0.38μM and 0.31μM, respectively. About 40-fold higher concentrations of Zileuton sodium also reduced the production of PGE2 with a IC50 of 16μM.