Interrelationships between the chemical structure of synthetic entities, their platelet aggregation inhibitory potency and their cellular toxicity, based on in vitro experiments.

: Striking relationships were observed, in vitro, between the molecular constitution of synthetic entities, their aggregation-inhibitory potency (as determined in ADP-induced human blood platelet aggregation), and their cellular toxicity (as assessed by their inhibition of cultured mouse fibroblast L-cell growth). Effects exerted on platelets tended to reflect interactions between the molecules' aggregation-inhibitory specific functions and the platelets' corresponding target sites, while fibroblasts were generally more susceptible to the molecular constitution's hydrophobic character. The hyperbolic relationships between concentrations effecting 50% inhibition and slopes of concentration-response curves reflect net activity from both specific and nonspecific receptor site interactions, with the latter being dominant, and indicated that the assays approximated equilibrium systems. Plotting logarithm values of concentrations effecting 50% inhibition against logarithms of reciprocal slopes for concentration response curves yielded multiple regression coefficients of R = 0.97 (platelet aggregation-inhibitory potency) and R = 0.98 (fibroblast growth-inhibitory potency).