The pharmaceutical industry is striving to develop oral pharmaceutical dosage forms to improve patient compliance. As the number of poorly soluble active ingredients included in oral pharmaceutical dosage forms increases, the development of advanced methods to evaluate their release is also required to successfully mitigate the risk of bioequivalence.
The objective of this master's thesis is to develop a dissolution-permeability method to evaluate the release of weakly basic, poorly soluble active ingredient contained in an amorphous solid dispersion (ASD) containing hydroxypropyl methylcellulose acetate succinate. We developed a biphasic method in microdissolution vessels on the MicroFLUXTM system, testing different method approaches and 4 different combinations of dissolution media: Sunflower oil – FaSSIF pH 6,5, Octanol – FaSSIF pH 6,5, Octanol – Phosphate buffer pH 6,5 and Octanol – SGF pH 1,6 + FaSSIF(x3) (triple concentrated medium FaSSIF). For the final evaluation of the studied samples, we chose a method that is at the same time simple to perform, repeatable, has adequate discriminatory power and biological relevance. The combination of the media octanol – FaSSIF 6,5 proved to be optimal, and we tested 15 ASD samples prepared under different process parameters using the hot-melt extrusion (HME) method. After performing all experiments using the biphasic method, we selected two samples that showed the greatest comparability with the original product and three samples for which in vivo data were available and also analysed them using the MicroFLUXTM membrane method with SGF pH 1,6 and FaSSIF pH 6,5 as donor media and 20 mM HEPES 1% SLS as acceptor media.
Both methods contributed significantly to elaborate the influence of critical process parameters (temperature, screw speed, amount of polymer used at HME and extrudate miling process) on the release profile of the drug in the form of ASD and the development of the final dosage form. In addition, the methods also contribute to the understanding of biorelevant dissolution-permeability processes (precipitation, supersaturation and colloidal structures) and to the establishment of an in vitro – in vivo correlation.
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