As a fundamental principle of science, this should be quite obvious that one should NOT develop or use product dependent methods or parameters to characterise the product itself. However, this is precisely the practice in the pharmaceutical area for product development and/or its evaluation i.e. everyone seeks/develops and uses a product dependent dissolution method.
This is clearly an example of a mindset which is obviously incorrect and scientifically invalid. It appears that this mindset has been created by the practice of pharmacopeial testing. Most pharmacopeial tests (e.g. USP) are drug and/or product dependent, however, these should be considered scientifically invalid or useless. The reason being that if a dissolution test is product dependent, then, it will not be possible to establish whether observed dissolution characteristics are because of the product or due to the experimental conditions used. Therefore, it should be noted that one cannot rely on product dependent (e.g. pharmacopeial) methods to establish dissolution characteristics of a product, thus its quality.
To evaluate the quality of a drug product, the dissolution method must be product independent. Therefore, developing product dependent dissolution methods for any purpose i.e. QC, discriminatory, bio-relevant, IVIVC, bio-waiver, QbD etc should be considered a mistake and complete waste of time and resources.
At present, vessel based dissolution tester with crescent shape spindles (link) has been suggested for product independent dissolution testing, thus not only it provides unbiased and scientifically valid dissolution testing, but also help in saving large resources.
