The application of statistical moment theory to the evaluation of in vivo dissolution time and absorption time.

Moments analysis has been applied to the calculation of mean (in vivo) dissolution time (MDT) and mean absorption time (MAT) from plasma level of drug versus time data. Methods for accurately estimating the MDT under varying conditions, limitations of the methods, and interpretation of the data are presented. The importance of accurate estimates of the terminal rate constant (lambda 2) and the drug concentration at the time of withdrawing the final plasma sample (Cz) is emphasized in connection with extrapolation to t = affinity. The appropriate use of a logarithmic trapezoidal equation for calculating the area under the moments curve (AUMC) is shown to increase the accuracy of estimating MDT.