Program for evaluating drug dissolution kinetics in preformulation.

The in vitro dissolution kinetics of various drugs were studied at different experimental conditions using both a centrically rotating disc method and a modified excentrically rotating disc method. The combination of these two methods provides a preformulation program that includes many important pharmaceutical and biopharmaceutical parameters related to drug dissolution. The influence of the hydrodynamic conditions on the dissolution rate was demonstrated and the intrinsic dissolution tendency was obtained. Further, the acid dissociation constant, diffusion coefficient and enthalpy of dissolution can be calculated from data obtained from the rotating disc experiments. The relationship between dissolution rate and aqueous solubility of each drug tested is also considered.