The main goal of this study is to develop a floating tablet of famotidine using hot melt extrusion coupled (HME) with Fused deposition modeling FDM 3D printing technology. Seventeen different formulations were prepared to obtain printable HME filaments. Hydroxypropyl cellulose (HPL-LF), hydroxypropyl cellulose (HPLC-EF), Hydroxypropyl Methylcellulose (HPMC-E5), and Ethyl Cellulose (EC) were used as polymeric carriers with 10% (w/w) famotidine. Polyethylene Glycol 1500 (PEG-1500) was used as a plasticizer. The resulting physical mixtures were then extruded using an 11 mm twin-screw co-rotating extruder (Thermo Fisher Scientific, Waltham, MA, USA). The HME filaments were then printed using an FDM-3D printer (Prusa i3 3D desktop printer, Prusa Research, Prague, Czech Republic) with a thickness of 0.4mm, line pattern, and 100% infill at 180 °C printing temperature. Famotidine, polymeric carriers, other excipient, filaments, and 3D printed tablets were analyzed to determine the physical state of famotidine by using a Differential Scanning Calorimetry (DSC). The in-vitro drug release profile of the printed tablets was evaluated. Five filaments (M10, M11, M15, M16, M17) out of seventeen were successfully printable. The tablets were printed in a line pattern and 100% infill with a hollow shape to have a low-density tablet that may reach the target of floating on the surface of the stomach for a more extended time. The famotidine DSC thermograms showed an endothermic melting peak at 163.5 °C. This endothermic peak disappeared in the extruded filament and the 3D-printed tablets. The disappeared peak indicates complete solubilization of famotidine in the polymeric carrier for all Five formulations. Drug content tests were performed from the best-printed tablets for M10, M11, and M17. The accepted formulations for further investigation were M10 and M17, respectively, which showed a release for 9 hours and 8 hours. The floating profile for M10, M11, and M17 was successful for around 8 hours. HME revealed the great potential to develop suitable filaments for FDM-3D printing. The formulation compositions and printing design and pattern are the keys to developing 3D printed floating tablets for famotidine
