3D printing of high drug loaded dosage forms using thermoplastic polyurethanes

It was the aim of this study to develop high drug loaded (> 30%, w/w), thermoplastic polyurethane (TPU)-based dosage forms via fused deposition modelling (FDM). Model drugs with different particle size and aqueous solubility were pre-processed in combination with diverse TPU grades via hot melt extrusion (HME) into filaments with a diameter of 1.75 +/- 0.05 mm. Subsequently, TPU-based filaments which featured acceptable quality attributes (i.e. consistent filament diameter, smooth surface morphology and good mechanical properties) were printed into tablets. The sustained release potential of the 3D printed dosage forms was tested in vitro. Moreover, the impact of printing parameters on the in vitro drug release was investigated. TPU-based filaments could be loaded with 60% (w/w) fine drug powder without observing severe shark skinning or inconsistent filament diameter. During 3D printing experiments, HME filaments based on hard TPU grades were successfully converted into personalized dosage forms containing a high concentration of crystalline drug (up to 60%, w/w). In vitro release kinetics were mainly affected by the matrix composition and tablet infill degree. Therefore, this study clearly demonstrated that TPU-based FDM feedstock material offers a lot of formulation freedom for the development of personalized dosage forms.