Orally disintegrating films: The effects of water content on disintegration and mechanical properties

Abstract Orally disintegrating films (ODFs) are one of the most important pharmaceutical oral dosage forms. However, it has been noted that the hygroscopicity of ODFs damages their stability and mechanical strength. We prepared model ODFs with three different water contents by storage under different relative humidity conditions in order to examine the effect of the water content on the films’ mechanical properties and the disintegration time. We used three molecular-weight (MW) grades of hydroxypropyl celluloses (HPCs), polyvinyl alcohol (PVA) and pullulan (PUL) as film-formers, and glycerin (GLY) as a plasticizer. With increases of the water content, the ODFs showed significantly decreased tensile strength but no marked change in disintegration time. Water content had the greatest effect on the PVA films containing GLY (10–20%). In addition, PUL films showed the highest water adsorption under all humidity conditions but maintained their excellent mechanical properties. We also elucidated the hygroscopicity of the ODFs formulated with the different polymers and plasticizer by means of a dynamic vapor sorption (DVS) analysis. Our findings provide useful information about the effects of different water contents and storage conditions on ODFs.