Relationship between structure and activity of aspirin-related compounds on the inhibition of in vitro platelet aggregation.

Thirteen aspirin-related compounds were tested for inhibitory activity on platelet aggregation in human platelet rich plasma (PRP) induced with ADP, collagen and arachidonic acid. The following structure-activity relationships were found: none of the functional groups used to replace the acetyl group retained the significant antiaggregant activity of aspirin; anti-aggregant activity was enhanced when the carboxylic group was replaced with a hydroxyl or an acetylated hydroxyl group. The activity of these mono and diacetylated pyrocatechol derivatives was unaffected by incubation of PRP with sodium salicylate.