Drug Dissolution Testing

Dear experts:

In the area of simulation and modelling, including developers of commercial software for such, note that I may not be able to argue with you regarding your methodologies of data analysis, modelling and/or simulation aspects as this is not my area of expertise; however, I know with certainty that you would require valid and accurate data for your analysis purposes. The difficulty is that you would not have access to such valid and accurate data at least for the evaluation of tablet or capsule products for the prediction of plasma drug levels or profiles. That is, in vitro drug dissolution results which represent or simulate in vivo dissolution and by extension plasma drug levels or profiles. You would require such data to validate your simulation or modelling outcome at least for the product development and manufacturing stages. Unfortunately, no one, at present, is generating, or can generate, valid in vitro dissolution data, thus your efforts of conducting simulation/modelling are regrettably of no use and would not help the industry, regulatory authorities or anyone else. Please, do not make claims of the successes and usefulness of such exercises.

One of the main reasons for not being able to obtain valid in vitro dissolution or drug release data is that the recommended and required (e.g. from USP and FDA) dissolution testers for such purposes have never been shown to provide valid and accurate dissolution results i.e. these testers have never been validated for their intended use or purpose. Vendors/manufacturers make extraordinary efforts and take pride in providing “compliant” testers i.e. meeting or exceeding “physical or fixed” specifications according to the pharmacopeial (such as USP) requirements; however, unable to validate the testers as dissolution testers. For example, no vendor, at present, can provide you valid in vitro dissolution results if given a blinded sample of a tablet/capsule product. Therefore, in this respect claims made by the vendors are also not accurate that they are selling or manufacturing dissolution testers. At best, the only claim they can, or should, make is that they are selling simple stirrers. Perhaps more disturbing is the fact that these stirrers when used as required for dissolution evaluations, because of their design and operation limitations and flaws, cannot provide valid and accurate dissolution results which is documented extensively in the literature.

In short, please use and promote the simulation and modelling techniques with care and certainly use extra caution in making claims for such about the future expectations and successes.

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