Extrusion-Based Three-Dimensional Printing of Metronidazole Immediate Release Tablets: Impact of Processing Parameters and in Vitro Evaluation

Abstract Purpose The current study assessed the potential of a pneumatic 3D printer in developing a taste-masked tablet in a single step. Metronidazole (MTZ) was chosen as the model drug, and Eudragit® E PO was used as a taste-masking polymer to produce taste-masked tablets. Methods The study focused on optimizing processing parameters, such as the nozzle's printing speed, the printhead's heating temperature, and the pressure. Oval-shaped tablets were printed with a rectilinear printing pattern of 30% and 100% infill and evaluated for in vitro drug release and taste masking. The 3D-printed tablets are also characterized using Differential Scanning Calorimetry (DSC), Fourier-transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy (SEM). Results The infill density impacts the drug release profile of the tablets. F9, F10, and F11 displayed desired printability among the formulations, with F9 and F10 exhibiting over 85% drug release within 60 min in the in vitro dissolution study. The F9 formulation, with 30% infill, effectively masked the bitter taste of MTZ in the in vitro dissolution study carried out in a pH 6.8 artificial salivary medium. The observed release was below the tasting threshold concentration of the model drug. Conclusion In summary, 3-dimensional extrusion-based printing combines the effects of hot-melt extrusion and fused deposition modeling techniques in a single-step process, demonstrating potential as an alternative to the fused-deposition model 3D printing technique and warranting further exploration. Graphical Abstract