Pharmaceutical community is developing new approaches for a more personalized treatment. 3D printing is one of the technologies that enables the production of solid dosage forms with a tailored dose, if needed. In the doctoral dissertation, we focused on two 3D printing technologies: fused deposition modelling and binder jetting.
In fused deposition modelling, the 3D printer converts the incoming material - filament (1.75 mm thick drug loaded polymer thread) into the dosage form at an elevated temperature. Firstly, we identified the printing parameters that affect the critical quality attributes of tablet disintegration time and tablet mass uniformity. Manufacturing of filaments via hot-melt extrusion technology involves elevated temperatures with potential drug degradation. We developed a preparative method employing differential scanning calorimetry, which is able to simulate the occurrence of the total impurities of the model drug in the filament after extrusion. The presented methodology enables quick screening of potential filament compositions to ensure sufficient thermal stability of the drug substance during processing. Once the filament is prepared, it should have adequate mechanical properties to effortlessly pass through the printhead. Otherwise, the filament will break or jam the feeding mechanism. We have identified a simple mechanical surface stiffness test that through predictive statistical model assesses filament feedability. In addition, we successfully predicted the reproducibility of certain critical attributes of printed tablets based on the mechanical and rheological properties of the filaments.
In binder jetting, the deposited powder blend is bound by the binding liquid into an orodispersible solid dosage form. Printed tablets may be susceptible to damage during handling due to poor mechanical properties. In the doctoral dissertation, we identified the printing parameters that improve the mechanical properties of printed tablets based on model formulation. Contrary, the influence of the binding liquid composition on the mechanical properties was negligible.
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