Current practices of dissolution testing invariably use paddle and basket apparatuses. In fact, describing a dissolution test almost always assumes that the tests been conducted are using these apparatuses.
The main objective of a dissolution test is to evaluate or predict dissolution characteristics of a product in vivo, mostly in humans. This link, or predictability aspect, is often referred to as in vitro-in vivo co-relationship (IVIVC).
On the other hand, a supporter of this test often propagate (market) it as a means to facilitate the development of products and later as a quality control test for monitoring batch-to-batch consistency in the production of pharmaceutical products for human use.
In reality, the test is a variation of a simple extraction-based analytical test, but its applications are large and powerful. The test is considered to provide an in vitro simulation of the release and dissolution of the drug in the human GI tract. Therefore, the first and foremost requirement for conducting this test is to make sure (validate) that the extraction process simulates the GI tract environment as closely as possible. In addition, like any other analytical test, the dissolution test should also have an acceptable level of repeatability and reproducibility.
These extraction tests, known as drug dissolution tests, are mostly conducted using paddle and basket apparatuses. These apparatuses have been in use for a long time. However, their relevance to simulate the required GI tract environment and reproducibility aspect appears to have never been established. In other words, these apparatuses have never been validated for their intended use, in particular using pharmaceutical products for human use. For any analytical chemistry test, including a dissolution test, to be acceptable for general use its appropriate validation is essential. Without the validation, the results obtained from the tests or apparatuses may be of limited value or use.