Study on controlling 3D printed drug release rates based on model structural adjustment

As an emerging technology, 3D printing facilitates the fabrication of complex preparations and enables controlled drug release. This study integrated semi-solid extrusion (SSE) and fused deposition modeling (FDM) to develop core-shell structured sustained-release tablets (CSRT) with varying release profiles, exploring how structural design influences release behavior. Propranolol hydrochloride was selected as the model drug. Drug-loaded cores with different filling rates were prepared using SSE and characterized for appearance, hardness, XRD, and release properties. Shells with varying release windows were fabricated using FDM. Subsequently, shells and cores were assembled. Micro-CT was employed for microstructural characterization, while drug assay and release properties were assessed. The results indicated that cores exhibited a good appearance, and the SSE process had no effect on the crystal type. Adjusting the filling rate allowed for slight modulation of drug release while the shell structure effectively prolonged drug release. The CSRT displayed no significant internal defects, and the assay met the United States Pharmacopoeia-National Formulary 2024 (USP-NF 2024) requirements. Adjusting release windows resulted in a sustained release ranging from 8 to 24 h, with the release profile conforming to first-order kinetics (R² values ranging from 0.961 to 0.999). These findings provide practical strategies for controlling drug release rates.