Inhibition of platelet aggregation by Flurbiprofen

Inhibitory activity of Flurbiprofen [2-(2 fluoro-4-biphenylyly) propionic acid], antiinframmatory compound, on normal human platelet aggregation was tested in vitro.At final concentration of 10-5M flurbiprofen inhibited completely the platelet aggregation which was induced by 10 and 3μg/ml (final concentration) collagen. Flurbiprofen of 10-3M (final concentration) inhibited the 2nd phase of platelet aggregation induced by 5×10-6M (final concentration) ADP, but did not inhibit the 1st phase of 2×10-6M (final concentration) ADP-induced platelet aggregation. When flurbiprofen was added after collagen-induced platelet aggregation or 2nd phase of ADP-induced platelet aggregation actually began, they were not inhibited by flurbiprofen.It seems that flurbiprofen has no influence on ADP itself, but inhibits the release reaction of platelets, induced by collagen or ADP.In scanning electronmicroscopic studies, many small balloon-like structures were found on the surface of ADP-or collagen-induced platelet aggregation mass, and these structures were seen to be round shape pseudo podes of platelets in transelucent electronmicroscopic studies. When ADP-or collagen-induced platelet aggregation was inhibited by flurbiprofen, gathering platelets atached each other with only slim pseudo pode. No particular changes were observed in the internal structure of platelet affected by flurbiprofen.