The use of Weibull distribution to describe the in vivo absorption kinetics.

The drug in vivo absorption rate reflects the distribution of drug molecules absorption times. For the latter the Weibull distribution is suggested and some examples taken from the literature are used to support the proposal. Cumulative absorption data for theophylline in man and pantothenic acid in rats are linearized in the double log coordinates, and the Weibull absorption model parameters are estimated by linear regression. The mean absorption time values calculated from these parameters are in close agreement with those assessed by the model-independent method.