In response to a recent query, I provided the following opinion, which others may also find helpful.
Your query has two parts: (1) scientific; and (2) regulatory. I will try to provide you with my opinion on both and hope it will work for you.
Scientifically speaking:
(1) There is no need to develop a discriminatory dissolution test. A valid dissolution test/method becomes a discriminatory test by default which must exist a priori to product development. This is a fundamental scientific principle.
(2) One cannot develop a dissolution or discriminatory dissolution test while developing the product. It does not matter if the product is of immediate release type or anything else.
(3) An official discriminatory dissolution medium does not exist. A dissolution medium represents the GI tract environment, which remains constant for all products (immediate and slow release), i.e., product independent. Therefore, dissolution media cannot differ for different drugs and their products. Requiring such would be illogical and unscientific.
(4) A requirement of product-specific dissolution tests should be considered unscientific. The method has to be product independent; otherwise, anyone can “develop” a method showing their product as per their liking.
Regulatory (“compliance”) aspect:
(1) As noted above, there is no logical/scientific reason to ask for a discriminatory test or its development.
(2) I realize that “experts,” including from within regulatory agencies, are implementing unlawful requirements as lawful/legal. Governments, e.g., US FDA, have started acting against such practices [1].
(3) The only suggestion I have, is to request your respective authority to provide an example of an officially recognized “discriminatory dissolution medium/method” which you can reproduce for your work/product. That is a medium/method shown to discriminate between “good” and “bad” products, clearly describing the “good” and “bad” products for human use.
You may find several articles/blogs on this site (https://bioanalyticx.com/) in support of the above. I hope this will help.