It is now generally recognised that the commonly recommended dissolution testers (paddle/basket) do not provide bio-relevant dissolution results. In addition, it is also well recognised that considering the flow dynamic within the vessels, these testers will provide highly variable and unpredictable results, thus would be of limited or of no use for routine testing as well.
Considering the need and importance of dissolution testing for product development and assessment, it is surprising that it is often suggested that in the absence of another “simple” alternative, one must keep using these testers. Such a suggestion is simply a marketing gimmick to promote the continued use of a flawed technique. It is almost like bicycle promoters suggesting that until and unless proper boats or ships are developed, people must keep using bicycles to cross rivers, because it is the only simpler and cheaper mean available and allowed for such transportation purposes.
On the other hand, the reality is that it is well known that it is the stirring and mixing mechanism, and environments within dissolution vessels which are causing the problem and require change or adjustment. In this regard, it has been shown that with a simple alteration, for example replacing paddle/basket spindle with the crescent-shaped spindle, not only are the artefacts of the paddle/basket apparatuses corrected but dissolution testing itself becomes relevant and extremely simple. For example: (1) one will be able to conduct product independent tests as opposed to product dependent tests, which is a scientifically incorrect practice to start with; (2) as the testing becomes product independent, one will avoid requiring method developments thus reducing cost and time; (3) the same set of experimental condition will be used for product development and QC purposes, thus again saving cost and time; (4) from the simplicity aspect, testers maintain the simple configuration and operation of the basket/paddle apparatuses.
Therefore, it is important to note that there is no reason that one should continue using a flawed system and keep generating useless data. A simpler and improved dissolution tester can be developed by simply modifying the currently used paddle/basket apparatuses e.g. by replacing a stirring element in it with another, such as with the crescent shape spindle.
