Poly(vinyl alcohol) 3D printed tablets: The effect of polymer particle size on drug loading and process efficiency.

Fused deposition modeling by 3D-printing is a rapid technique for the production of personalized drug dosage forms. One of the most delicate step of the whole process is the drug loading onto the thermoplastic polymer to obtain the drug-loaded filament used as feedstock for 3D FDM printers. With the aim of improving the drug loading, a systematic study on the influence of polymer size distribution on the quantity of drug able to adhere onto the polymer surface was conducted. Several solid mixtures were prepared, using five PVA batches (4000-5000 µm, 1000-2000 µm, 600-1000 µm, 250-600 µm, <250 µm) and Ciprofloxacin hydrochloride as active compound in different ratios. Operative specifics and printer's parameters were tuned for an optimal print of drug-loaded filaments into the desired dosage forms, i.e. cylindrical printlets, fully characterized in terms of homogeneity, process efficiency, physical properties, drug content and release kinetics. The PVA particle size affected the polymer ability to form homogeneous mixture with the drug and the efficiency of the extrusion process. In particular, finest PVA batches showed better processability and reduced the drug loss during the drug/polymer mixing and the extrusion process. Drug-loaded filaments with different drug concentrations were successfully printed and the obtained printlets dissolution profiles were almost superimposable, taking an important step for the future application of 3D-printing manufacturing process to obtain personalized galenic formulations.