These apparatuses:
- Lack of scientific merit and support. Experimental studies have shown that they will provide highly variable and unpredictable results because of poor product/medium interaction.
- Cannot be qualified/validated using commonly used industry-wide practices of qualifications for analytical instruments. In particular, they do not meet the requirements of design qualification (not fit for intended use) and operation qualification (cannot be qualified using a reference product).
- Require meeting undefined and unqualified requirements such as de-aeration of the medium and control of vibration in and around the equipment.
- Require drug and/or product-dependent experimental conditions. Therefore, it will not be possible to know whether dissolution characteristics reflect the products or the experimental conditions used.
- Do not differentiate between IR and ER products. The analyst must first know what type of release/dissolution to expect from the product and then use the design of the experimental conditions to provide the presumed released/dissolution characteristics.
- Are routinely used for evaluating drug products for human use (e.g., pharmacopeial testing). However, they have never been validated to demonstrate that they can provide bio- or physiologically relevant results.
- Are often used for quality control and to check lot-to-lot consistency purposes. However, a link of these apparatuses, and associated experimental conditions, to the quality of a product, and consistency thereof, is unknown or undefined. The only criterion used for this purpose is that the dissolution results must meet some arbitrary standards/tolerances. If the criterion is not met, it is assumed that the products may be of substandard attributes.
- Are expected to provide discriminatory tests which should be capable of showing formulation/manufacturing differences among products and/or batches. On the other hand, it is a well-known fact that these apparatuses frequently provide discriminatory results lacking any physiological significance or consequence.
- Do not simulate in vivo or physiological environment (stirring and mixing) thus, one cannot develop bio-relevant tests.
- Require tolerances be set lower than potency and content uniformity values. Thus, results will reflect the inaccurate and inappropriate quality of perfectly acceptable products.
Considering the above-mentioned deficiencies, results obtained using these apparatuses can easily be questioned/challenged for their validity and relevance.