COMPARISON OF IN-VITRO DISSOLUTION PROFILES BY CALCULATING MEAN DISSOLUTION TIME (MDT) OR MEAN RESIDENCE TIME (MRT)

The technique of calculating the statistical moments of MDT or MRT is commonly used to describe in vitro drug release profiles, especially those for dissolution controlled release products. Any mathematical method used to calculate these values must be able to differentiate curves of different shape and extent, and should have a minimum of errors. Seven methods, which are described in the literature, have been compared in terms of their applicability to characterize different model release profiles. The mean error of the values calculated was determined. Only two methods, which calculate MRT values, appear to be useful. These are the pragmatic plane geometry using the residence profile and the overlapping parabolic integration. Pragmatic plane geometry for calculating MDT values provides exact estimates, if a complete zero order release profile is investigated. In general, the applicability of all the methods is limited by the error and the ability to differentiate between curves, especially for zero order kinetics release, if values for a complete drug release are not available.