The worst possible advice: Adjust experimental conditions to achieve desired or expected dissolution characteristics of a product. Unfortunately, it is also the most common one.

A common query regarding drug dissolution testing is; how should I (scientist or analyst) get desired dissolution characteristics? The desired characteristics mean: (1) slower or faster dissolution results than observed; (2) discriminatory profiles; (3) bio-relevant or IVIVC results (4) QC- or batch-to-batch testing criteria, etc. Often such a question is not asked directly, but indirectly as to how should I (scientist or analyst) develop a dissolution method for my product, implying how to achieve a desired/expected dissolution characteristic of the product. It would be interesting to note that dissolution tests are conducted to evaluate impact of formulation/manufacturing on the drug release characteristics. Often the questioner does not provide (or cannot, because of confidential/proprietary reasons) the formulation/manufacturing attributes of the product. Then, how would someone be able to provide an appropriate response to such a question?

On the other hand, even without knowing the formulation/manufacturing attributes, people provide endless suggestions/recommendations of trying different experimental conditions (apparatuses, dissolution media, stirring speeds etc.) to achieve what a scientist or analyst is trying to achieve, i.e. desired dissolution results. How can such advice be considered valid or relevant? The current mindset, unfortunately, is to provide advice after advice as how to conduct dissolution tests – more appropriately how to play with experimental conditions to achieve certain desired dissolution results.

The purpose of dissolution testing and the queries, however, is very clear that the scientists/analysts would like to know dissolution characteristics of a product and not the available choices of experimental conditions.  Therefore, providing advice about selecting or playing with experimental conditions for dissolution testing, in particular product dependent, is clearly inaccurate and false help. One should be aware of such practices which may cause serious loss of time and resources.

To determine the value of a parameter/property, including dissolution, one requires a well-established and validated tester and method. Unfortunately, none of the apparatuses described including the associated methods (experimental conditions) are qualified and/or validated for the intended purposes i.e. to determine dissolution characteristics. Therefore, advices for conducting dissolution testing based on currently recommended apparatuses and/or experimental conditions become even more strange and a self-deceiving exercise. One should be extremely cautious in following such “help” or “advice”.

To conduct a dissolution test i.e. to evaluate dissolution characteristics of a product, one requires a common, and product independent, set of experimental conditions. The crescent shape spindle and associated experimental conditions have been suggested to address the difficulties and flaws of the current practices, thus providing an option for appropriate evaluation of dissolution characteristics of products.

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