Bio-relevant dissolution tests are highly desirable and are often referred to. It appears that such tests are commonly understood as intuitive expectations rather than a clearly defined scientific objective. This creates confusion, misunderstandings and leads to lack of progress in this regard. To avoid such confusion, the following may be considered as an appropriate definition:
“A bio-relevant dissolution test is a test which is conducted using experimental conditions representing GI tract environment, in particular intestinal, and capable of predicting in vivo response comparable to the actual blood concentration-time profiles obtained from the bioavailability/bioequivalence studies.”
It is essential to understand that a bio-relevant test must be conducted using appropriate and bio-relevant experimental conditions. Use of non-physiological test conditions such as de-aeration of dissolution medium, product dependent experimental conditions, inefficient or lack of stirring/mixing within dissolution vessels, etc., are to be avoided. Furthermore, the test conducted with appropriate test conditions must also be able to predict in vivo (blood) drug concentration-time profiles. For example, the predicted profiles should at least be able to differentiate between fast (e.g. IR) and slow release (ER) products as these would be from an in vivo study. Such a test should then be used to evaluate potential drug release characteristics of a test product. For further discussion of the subject and detailed methodology to calculate drug concentration-time profiles from dissolution results please see the links (1, 2).
