Application of Calcium Alginate Hydrogels in Semisolid Extrusion 3D Printed for the Production of Easy-to-Swallow Tablets

To maximize the potential of 3D printing, several technological issues must be overcome, especially in the case of semisolid extrusion (SSE), where the 3D model is built up through the well-defined extrusion of polymeric ink. Focusing on natural polymers, their physicochemical properties should be deeply investigated to evaluate 3D printability. This study aims to produce tablets easy to swallow, exploiting as 3D printing ink a crosslinked alginate hydrogel added of sorbitol, speculating that the plasticising action of sorbitol should allow to improve tablets' swallowability. Three different amounts of 70% sorbitol solution (5%, 15%, 25% v/v) are evaluated to identify the best composition in terms of both printing and technological properties. The data obtained from the chemical, rheological, and mechanical evaluation of each ink are related to the printing performance, to reach the best manufacturing reproducibility. Linear regression fitting study (r(2) = 0.9982) confirms the predictable relationship between residual mass of final platforms and sorbitol amount loaded. To characterize the final products, all dried batches are subjected to technological evaluation highlighting differences in the matrix softability as well as in the swelling/erosion properties after the interaction with biological fluids.