Mucosal route of drug delivery is recognised as suitable alternative to conventional drug administration routes (i.e. oral and parenteral), providing the possibility of more efficient local therapy with reduced systemic drug exposure as well as alternative application route for drugs that undergo extensive biotransformation in liver that leads to low and variable oral bioavailability. Nowadays, nanotechnology has been introduced to such delivery systems in order to improve their efficiency and safety. All this brings new challenges in evaluation of such formulations, prompting us to critically revise and upgrade the currently used methodology. In vitro release test is an important assay both in product development phase as well as in its quality control assurance. However, considering the diversity in formulations design, physicochemical and release characteristics of mucosal delivery systems, it is not possible to devise a single method which would be suitable for such purpose. This presentation is aimed to offer an extensive overview of currently available methodologies, both compendial and noncompendial, for in vitro drug release testing of mucosal delivery systems aimed for ocular, nasal, oromucosal, vaginal and rectal application. Critical parameters of such assays and instrumental setups will be discussed in details with a special focus on the evaluation of nanodelivery systems. In order to avoid unnecessary proliferation of equipment and method design, compendial apparatuses and methods should be used as a first approach in method development when applicable. Equipment set up, the selection of dissolution media type and volume, membrane characteristics, agitation speed, temperature, and assay analysis technique need to be carefully selected based on the properties of mucosal drug delivery system. The final goal of the method development is to obtain adequate simulation of conditions present in vivo at the application site. This would lead to development of novel biorelevant in vitro dissolution/release methods should that would enable better prediction of formulation performance in vivo and, preferably, the establishment of an in vitro/in vivo correlation.
Audience take away:
- The audience will get useful guidelines how to perform in vitro release testing of specific formulation aimed for mucosal delivery, that could be readily applicable in their laboratory
- Some practical, ready to use solution to the problems present in the field of drug release testing will be given, in relation to the apparatus setup, media preparation and selection, sampling etc.
- Critical analysis of the currently available methodology will allow the audience to avoid some of the common mistakes and obtain more accurate data
- This presentation might initiate new research lines