Although not generally recognized, current practices of dissolution testing seek to adjust experimental conditions to obtain desired or expected drug release/dissolution characteristics. The variations or adjustments in experimental conditions, which are commonly referred to as method development steps, often relate to the choice of apparatuses, RPMs or flow rates, media (nature and volumes), etc. Thus, current practices defeat the purpose of dissolution testing, which is supposed to be conducted to evaluate or establish drug release characteristics of a product, in particular, at the method development stage. In addition, most standards and requirements are based on selecting and setting experimental conditions rather than evaluating products.
For appropriate dissolution testing, the tests are to be conducted using product-independent and fixed experimental conditions. This will facilitate finding the actual drug dissolution or release characteristics of a product or help in knowing one’s product. If one keeps on changing the experimental conditions, one will never know the products’ true (dissolution) characteristics.