The effect of RA 233 on platelet function in vitro and after administration to man.

RA 233 inhibited human platelet adhesion and aggregation in vitro. However, the administration of 3 g daily to human subjects for one week caused no alteration in the same parameters of platelet function. The lack of effect of RA 233 in vivo is likely to be due to inadequate blood levels of the drug being attained by acceptable oral doses and it is, therefore, unlikely that this drug would have any beneficial effect on thrombogenesis.