Hydrodynamic Influences on Dissolution Testing Using Flow Channel Apparatuses

Abstract The extent and rate of solution formation are measured via dissolution testing. Contrary to expectations, the intrinsic dissolution rate ( IDR ) is not size‐independent, despite normalization of the sample area. By comparing different channel designs and sample diameters, the dimensionless boundary layer normalization factor ( BNF ) was developed to account for the size‐dependence discovered. With the derived velocity of the boundary ( v b ), the comparability of dissolution data generated with flow channel apparatuses was established, depending on the flow pattern under laminar flow conditions.