DISSOLUTION TESTING AS A PROGNOSTIC TOOL FOR ORAL-DRUG ABSORPTION - IMMEDIATE-RELEASE DOSAGE FORMS

Dissolution tests are used for many purposes in the pharmaceutical ind ustry: in the development of new products, for quality control and, to assist with the determination of bioequivalence. Recent regulatory de velopments such as the Biopharmaceutics Classification Scheme have hig hlighted the importance of dissolution in the regulation of post-appro val changes and introduced the possibility of substituting dissolution tests for clinical studies in some cases. Therefore, there is a need to develop dissolution tests that better predict the in vivo performan ce of drug products. This could be achieved if the conditions in the g astrointestinal tract were successfully reconstructed in vitro. The ai ms of this article are, first, to clarify under which circumstances di ssolution testing can be prognostic for in vivo performance, and secon d, to present physiological data relevant to the design of dissolution tests, particularly with respect to the composition, volume, flow rat es and mixing patterns of the fluids in the gastrointestinal tract. Fi nally brief comments are made in regard to the composition of in vitro dissolution media as well as the hydrodynamics and duration of the te st.