There is no argument that the drug dissolution characteristic of a product (tablet/capsule) is one of the most critical and critical attributes. It is, and will remain, one of the critical parameters to evaluate for the development and evaluation of the products.
However, the issue is how one should measure the parameter (dissolution characteristics of a product) i.e. percent drug dissolved/released at times from a product? Obviously, one requires an apparatus/procedure to determine that. It is the most basic and scientific requirement for determining any characteristic/parameter. The apparatuses/methods used must first be qualified/validated, i.e., a priori shown to be fit for the purpose. However, none of the suggested/recommended apparatuses/methods have ever been shown as qualified and/or validated for dissolution testing. These are no different or better for dissolution testing than the use of a kitchen blender at a slower rpm.
Therefore, it is very important and critical to note that any results obtained using the suggested/recommended apparatuses/methods, particularly basket and paddle, have no scientific merit or use for any purpose, including QC, IVIVC QbD, etc. One should be extremely cautious in drawing any conclusions based on data obtained using these unqualified and non-validated apparatuses.