Beeswax sacrificial support and latex curing for high-fidelity semi-solid extrusion 3D printed sustained-release...

Semi-solid extrusion (SSE) 3D printing offers significant potential for fabricating personalized oral dosage forms, thanks to its mild processing conditions. However, post-printing drying often induces structural collapse and deformation due to solvent evaporation, severely compromising geometric fidelity. While freeze-drying can mitigate deformation, it is time-intensive and yields highly porous structures with inferior mechanical strength. This study introduces a dual strategy employing a phase-change sacrificial support and thermal curing to overcome these limitations. A printable matrix was formulated using microcrystalline cellulose and hydroxypropyl methylcellulose (HPMC) as rheological modifiers, with Eudragit® RL 30D aqueous dispersion serving as the sustained-release polymer and beeswax as a sacrificial phase. The optimized tablets demonstrated superior mechanical integrity, with Young's modulus increasing by 67%. During thermal curing at 80°C, the dispersed Eudragit® RL pseudo-latex underwent coalescence and formed an insoluble matrix, creating an insoluble polymeric network that reinforced the structure and modulated drug release. Crucially, beeswax (melting range 62-67°C) provided mechanical support during the critical drying phase at 50°C, preventing structural collapse, before being sacrificially removed during the 80°C curing step. This approach successfully produced high-fidelity, diclofenac sodium-loaded tablets with tunable release profiles governed by the Eudragit® RL-to-HPMC ratio. These findings present a robust strategy for producing dimensionally stable, mechanically strong, and personalized sustained-release formulations via SSE 3D printing.