Correlations between diffusion rate constant, partition coefficient and biological activity of substituted benzoic acid

The diffusion rate constants (Kd) of a series of sixty-two substituted benzoic acid were determined in a Sartorius Absorption Simulator according to Stricker.In this model, transport was monitored under conditions simulating the diffusion of unionized molecules.The correlations between the diffusion rate constants and the n-octanol/water and eter/water partition coefficient are in agreement with the Wagner-Sedman theory.A significant correlation was also found between the diffusion rate constants and the biological activity of derivatives investigated (literature data).The possibility of considering the in vitro diffusion rate constants of the benzoic acids as a useful parameter in predicting the intensity of their biological activity is discussed.