There is no doubt that drug dissolution testing is an important and useful subject. However, currently used techniques and practices are generally not science-based and do not provide answers to questions people often ask. For example:
When apparatuses (dissolution tester) are sold by vendors, in particular Paddle and Basket, they do not provide evidence that the testers are, indeed, capable of providing dissolution characteristics of a product (e.g. see link). The capability of a tester as a dissolution tester can only be provided if a vendor provides dissolution characteristics of a reference product or a test product given by the purchaser. Presently, the vendors are only providing apparatuses, which meet the expected physical specifications of a reproducible stirrer or mixer. They are not capable of providing the dissolution characteristics of a product in particular for human use.
A formulator or drug developer would not be able to develop a product using the testers, in particular the Paddle and Basket, because testers do not have defined and set experimental conditions capable of reflecting a product’s behavior in vivo (humans). The formulator requires an acceptable set of experimental conditions to evaluate and develop products which are not available.
A manufacturer cannot use these apparatuses to establish the reproducibility or consistency in lot-to-lot production, as consistency of the testing itself is unknown, or at best extremely high.
The evaluator, in particular for regulatory purposes, requires evidence that indeed the dissolution test employed can differentiate between an acceptable product and an un-acceptable product. These acceptability criteria require that dissolution tests should predict, or link, dissolution behavior to the in vivo results i.e., should have a successful IVIVC. However, on the other hand, it is very well known that the current approaches of testing, in particular using the Paddle and Basket apparatuses, almost never predict the in vivo characteristics of a product. Therefore, an evaluator will always have difficulty in making a decision based on the data provided, using these dissolution apparatuses.
The obvious question is why are we continuing with these practices and making claims of “success” and “usefulness” of the current practices? The answer is that old traditions take a long time to die.
