These apparatuses:
- Lack 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 are a reflection of the products or of 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 experimental conditions design 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 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.
