FDM 3D-printed oral dosage form of prednisolone – Improvement of printability and influencing drug release

The customisation of solid oral dosage forms is essential for maximising efficacy, minimising harm, and providing patient-centred care. Fused Deposition Modelling (FDM) 3D-printing (3DP) is current research of interest within the pharmaceutical industry to produce personalised 3D printed oral "tablets" (printlets) by utilising drug-loaded polymer filaments. Due to the novelty of such technique within the pharmaceutical industry, the printability of many dosage forms and the effect of physical parameters such as the geometry of printlets requires additional research. In this work, the printability of prednisolone (PDL) loaded semi-crystalline polyvinyl alcohol (PVAl) filament was investigated via various characterisation and analytical techniques, such as optical microscopy, x-ray micro-computed tomography (μCT), powder x-ray diffraction (pXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), melt rheology (at 215 ℃), and dissolution testing. Using these techniques, it was shown that the viscosity of the prednisolone-loaded polyvinyl alcohol (PVAl-PDL) drastically decreased with increasing shear rate beyond 5 s^-1 due to the presence of prednisolone which affected the macro and microscopic qualities of the printlets upon using the same printing settings (215 ℃) as for the polymer only. It was further shown that the geometry (structure) of the printlets had a significant influence on the drug release with the most influential factor being the contact surface area to volume ratio in contrast to other parameters. The results presented in this work show the ability of FDM 3DP within the pharmaceutical industry and the possibility to control the drug release, and the macro and microstructure qualities of the printlets.