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Ticagrelor (AZD6140) is the first reversibly binding oral P2Y12 receptor antagonist in development for reduction of clinical thrombotic events in patients with acute coronary syndromes. The purpose of our studies was to determine the effect of single-ascending doses of ticagrelor in healthy subjects. In two randomised, double-blind, placebo-controlled single ascending dose studies, healthy subjects received oral doses of 0.1–100 mg or placebo ( n = 25) and 30–400 mg or placebo ( n = 13). Absorption of ticagrelor was rapid [median time to peak plasma concentration (tmax) 1.3–2 h], as was the formation of its main (active) metabolite, AR-C124910XX (tmax 1.5–3 h). For both ticagrelor and AR-C124910XX, the peak plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 to infinity ( $$ {\hbox{AU}}{{\hbox{C}}_{0 - \infty }} $$) increased in an apparently dose-proportional manner over the dose range studied, indicating linear pharmacokinetics. The mean terminal-phase half-life (t½) was approximately 7–8.5 h for ticagrelor and 8.5–10 h for AR-C124910XX; AR-C124910XX exposure was approximately one third that of ticagrelor. Inhibition of platelet aggregation (IPA) was dose related and was nearly complete at 2 h (mean 88–95%; final extent, with 20 µM adenosine diphosphate ADP) at doses of 100–400 mg. Linear and predictable pharmacokinetics of ticagrelor and AR-C124910XX were observed. A consistent and high IPA was maintained over 2–12 h, gradually decreasing with declining plasma concentration starting around 12 h post-dose, indicating that the IPA is reversible. Ticagrelor was well tolerated, with no serious or dose-related adverse events or notable changes in laboratory values observed. [ABSTRACT FROM AUTHOR]

Prasugrel is a novel thienopyridine prodrug metabolised to an active metabolite that binds irreversibly to the platelet P2Y12 receptor and inhibits adenosine diphosphate (ADP)-induced platelet aggregation. We compared prasugrel pharmacokinetics, pharmacodynamics, and tolerability in healthy Chinese, Japanese, Korean and Caucasian subjects. In an open-label, single-centre, parallel-design study, 89 healthy subjects (25 Chinese, 20 Japanese, 22 Korean and 22 Caucasian) aged 20–65 years were given a prasugrel 60-mg loading dose (LD) followed by daily 10-mg maintenance doses (MD) for 7 days and then 5-mg MD for 10 days. Plasma concentrations of prasugrel’s active metabolite and inhibition of ADP-induced platelet aggregation (IPA) were determined. Mean exposure to prasugrel’s active metabolite in all treatment regimens was higher in each of the Asian groups than in the Caucasian group, although there was considerable overlap between individual exposure estimates in Asians and Caucasians. The mean IPA was also higher in Asians than in Caucasians following a prasugrel 60-mg LD, although the difference did not consistently achieve statistical significance. Prasugrel 10-mg or 5-mg MD produced statistically significantly higher IPA in each Asian group compared with that in the Caucasians. Prasugrel was well tolerated during the LD and MD regimens by all groups. Mean exposure to the prasugrel active metabolite following prasugrel 60-mg LD and during daily 10-mg or 5-mg MD was higher in each of the Asian groups than in the Caucasian group, which resulted in greater platelet inhibition. [ABSTRACT FROM AUTHOR]

The pharmacokinetics of sulfinpyrazone, and the plasma levels of its sulfide and sulfone metabolites, have been determined after a single oral dose (400 mg) and during steady-state conditions (4×200 mg daily for 6 days) in healthy female volunteers. The plasma half-lives of sulfinpyrazone, the sulfone and the sulfide were 3.7, 3.2 and 14.7 h, respectively, during steady-state. After a single dose and during steady state conditions the half-lives of sulfinpyrazone and the sulfone did not differ significantly. The trough plasma levels of the sulfide metabolite exceeded those of the parent compound in four of the six volunteers on the last day of the study. The data suggest that in man the most likely candidate for the prolonged inhibition of platelet aggregation observed after treatment with sulfinpyrazone is its sulfide metabolite, because of its prolonged elimination. [ABSTRACT FROM AUTHOR]