Fabrication of Shape-Memory Polymer-Based Drug Delivery Platforms: Design and Process Parameter Optimization

The combination of 3D printing and shape-memory materials has provided new insights into the design and manufacture of customized medicines by enabling the unique design of drug delivery systems while allowing them to retain specific predefined shape until triggered by external stimuli such as body temperature or gastrointestinal pH. In this study, we investigated the feasibility of utilizing fused deposition modeling (FDM) 3D printing to fabricate a shape-memory polymer-based drug delivery platform specifically designed in helical structure. This platform can be compressed and temporarily fixed into tablet-like shape for patients to easily swallow before reverting back to its original shape in stomach. Furthermore, this study investigated the influence of 3D model design parameters (e.g., helix diameter, height, turns) and process parameters (e.g., layer height, nozzle temperature, programming temperature for shape fixation) on shape fidelity and shape memory behavior of the platform. The findings demonstrated that the platform with helix shape was most effectively transformed into a tablet-like shape when the programming temperature was close to the glass transition temperature (T_g) of printing filament. However, when the temperature exceeded T_g, the platform became too soft, thus resulting in 3D structure distortion and decreasing in shape fidelity. Additionally, shape memory testing showed that the developed platforms were able to revert to their original shape with a recovery ratio of 40-50% in 30 minutes when subjected to 0.1N hydrochloric acid at 37 °C. These findings provide crucial insights for future research on utilizing this platform for stomach-specific drug delivery, particularly in gastroretentive approaches.