KF 13218 is a selective, potent and long lasting thromboxane B2 (TXB2) synthase inhibitor with an IC50 value of 5.3±1.3 nM.

TXB2:5.3 nM

KF 13218 effectively suppresses arachidonic acid-triggered thromboxane B2 synthesis in human intact platelets, showing a notable inhibitory concentration (IC50) of 5.3±1.3 nM. This potency is approximately fivefold greater against intact platelets than against the microsomal enzyme, indicating a significant specificity. Remarkably, the compound's ability to inhibit thromboxane synthase within platelets remains even after the extracellular substance is eliminated. Furthermore, KF 13218 demonstrates inhibition of both human and bovine platelet thromboxane synthase with IC50 values of 27±5.8 nM and 36±6.9 nM, respectively, without affecting cyclooxygenase or 5-lipoxygenase at doses up to 100 μM nor antagonizing thromboxane A2/prostaglandin H2 receptors.

KF 13218, when administered orally at a dosage of 0.1 mg/kg, effectively prevents mortality caused by sodium arachidonate in rabbits. Additionally, dosages ranging from 0.03 mg/kg to 3 mg/kg in rats lead to a dose-dependent inhibition of thromboxane B2 production in serum, with the effect maintained for up to 72 hours.