1072 experimentally obtained and simulated time evolution of the regions with different physicochemical properties, i.e. dry glassy, swollen glassy and gel regions, is shown. The results are also compared with VIS/FTIR experimental study (by Kazarian et al.) (12). The three complementary approaches, pharmacopoeial MRI in flow-through cell, theoretical modeling of HPMC, and VIS/FTIR, were found to provide consistent results in terms of temporal evolution of the matrix. ACKNOWLEDGMENTS The work was supported by the Polish Ministry of Science and Higher Education grant N N518 407438. We are thankful to Dr. B. Tomanek from National Research Council Canada, Institute for Biodiagnostics (West), Calgary, Canada, and to Andrew Procca from National Research Council of Canada, Institute for Biodiagnostics, Winnipeg, Manitoba, Canada, for critical reading of the manuscript. 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