Pharmacokinetics and cyclooxygenase inhibition of itazigrel in normal volunteers after single oral doses.

The pharmacokinetics and cyclooxygenase inhibition of itazigrel were studied in normal male volunteers. In a low-dose study, subjects received a single oral dose of 5-100 mg of itazigrel. Serum concentration and the production rate of thromboxane B2, an indicator of cyclooxygenase activity, were monitored for 48 h. In a high-dose study, single oral doses of 100-600 mg of itazigrel were administered. Serum concentrations were monitored for 72 h. Production rates of thromboxane B2 and leukotriene B4, an indicator of lipoxygenase activity, were monitored for the first 2 h after drug administration. Pharmacokinetics of itazigrel appeared to follow biexponential elimination with an alpha half-life between 1.2 and 2 h and a beta half-life between 23 and 28 h. The relationship between dose and area under the serum concentration curve was nonlinear, probably due to saturable systemic metabolism or saturable first-pass metabolism. Cyclooxygenase inhibition by itazigrel was related to the serum concentration by the Hill's equation with a mean IC50 value of 2.1 ng/mL. Itazigrel did not appear to affect the lipoxygenase activity in the study.