 Venous blood samples are collected by venipuncture into two 4.5-mL draw BD vacutainer tubes containing 0.105M buffered sodium citrate 3.2 at 08.00 hours in the morning before taking the agent and after the last dose of the study drug. Platelet-rich plasma PRP from subjects in A group is mixed with increasing proportions of that in C group, with one untreated subject serving as the control for one treated subject. The proportion of control platelets mixed with inhibited platelets is calculated based on platelet numbers, starting at 10 and increasing by 10 increments. So as the PRP in B group. 