Orodispersible films prepared by hot-melt extrusion versus solvent casting

Abstract

This study investigated the influence of solvent casting and hot-melt extrusion manufacturing methods on the physical, chemical, and functional properties of orodispersible films with the same composition and incorporating a poorly soluble active pharmaceutical ingredient (API). Both techniques produced films that met pharmaceutical standards for disintegration and dissolution times. Solvent casting, the most used method, yielded films with homogeneous distribution of plasticizer, smoother textures, and greater flexibility. In contrast, hot melt extrusion, a solvent-free process, resulted in slightly brittle films due to uneven plasticizer integration, highlighting the impact of manufacturing parameters on film structure. Despite these differences, both methods exhibited similar chemical stability under varying humidity conditions, with API recrystallization occurring at higher humidity, particularly in films prepared by solvent casting. Increased humidity significantly reduced tensile strength, as water acted as a plasticizer, promoting API recrystallization and weakening the structure. Stability tests revealed that hot melt extrusion films retained their structural and chemical integrity over 12 months when stored in impermeable packaging bags. This study confirms the suitability of hot melt extrusion for industrial-scale ODF production, offering advantages such as a solvent-free process, reduced environmental impact, and adaptability for modern pharmaceutical manufacturing, provided formulation and process parameters could be carefully optimized.