Compound 1 inhibits aggregation of PRP induced by 5 μM ADP (IC50: 13 ± 5 μM) and 5 μM TRAP (IC50: 29 ± 6 μM) and inhibits the aggregation of washed platelets induced by 5 μM TRAP (IC50: 3.4 ± 0.4). Citrated PRP or washed platelets (250 × 109/L, 100 μM CaCl2, 50 μM MgCl2, 200 μg/mL fibrinogen) was treated with compound 1 for 15 minutes at 37°C before initiating aggregation with 5 μM ADP or 5 μM TRAP (PRP and washed platelets). Aggregation was calculated as the percentage of the maximum initial slope of the change in light transmittance from 15 to 90 seconds. Results from 1 representative experiment from each condition are shown, of a total of 3. Note that data are from different donors tested on different days.