While surfing the Internet, I found two very interesting and useful video clips showing the digestion process in the human gastrointestinal tract. Click on the links to watch the videos (video1 and video2).
After watching these videos, it is very difficult to imagine that people would like to use the currently suggested dissolution apparatuses, in particular paddle and basket. Appropriate dissolution testing would require a fairly rigorous stirring and mixing process, as can be seen in the videos. Currently used apparatuses do not provide any mixing and stirring, in particular the paddle and basket.
An even more irrational and unscientific aspect is that people tend to emphasize the requirement, that the dissolution testing should be conducted using a disturbance free environment. Such requirements are reflected by the suggestions that apparatuses must be free from all forms of (almost nonexistent) vibrations and their effects. Furthermore, if a product moves, or floats, or is expected to move or float, within a dissolution vessel then often it is recommended that it must be caged in a so called a sinker to stop this floating and moving aspect. In addition, it is often recommended that a dissolution test at present should preferably be conducted using a de-aerated medium. It is not clear how this de-aeration step got incorporated in the dissolution testing when it is not relevant to the physiological environment.
From the videos and the comments above, it is clear that the currently used apparatuses provide an incorrect environment for dissolution testing. Furthermore, the suggested experimental conditions, such as de-aeration, vibration free environment and the use of a sinker or fixing product’s position are irrelevant. The data obtained using these apparatuses and the recommended experimental conditions would be of limited or no use.
