Figure 2.

Titration and reversibility of inhibition of platelet Cox-1 by ibuprofen, celecoxib, valdecoxib, rofecoxib, etoricoxib, and aspirin. Washed platelets were treated with inhibitor for 25 min before the stimulation of Cox activity with calcium ionophore. After a 10-min reaction, the amount of TXB₂ produced was determined by EIA (○). To determine inhibitor reversibility, platelets were treated with each inhibitor for 25 min, and the platelets were then washed twice with fresh buffer before ionophore stimulation and TXB₂ production as above (□). The data represent the average of titrations from at least three blood donors, except for aspirin (n = 2). The error bars represent the SEM of each value.