127654-03-9

KF 13218 inhibits human and bovine platelet thromboxane synthase with IC ₅₀ values of 27±5.8 nM (mean±S.E.M.) and 36±6.9 nM, respectively. KF 13218 does not inhibit cyclooxygenase or 5-lipoxygenase up to a dose of 100 μM and does not antagonize thromboxane A2/prostaglandin H2 receptors. KF 13218 inhibits arachidonic acid-induced thromboxane B2 production by human intact platelets with an IC ₅₀ value of 5.3±1.3 nM. The IC ₅₀ value of KF 13218 for the intact platelets is about 5 times lower than that for the microsomal enzyme. The inhibition of thromboxane synthase in platelets by KF 13218 is sustained after removal of the extracellular compound.

After oral dosing in rat from 0.03 mg/kg to 3 mg/kg, KF 13218 dose-dependently inhibits the thromboxane B2 production in serum, and the inhibition is retained for 72 h. KF 13218, at a dose of 0.1 mg/kg p.o. prevents mortality induced by sodium arachidonate in rabbit.