Development of a 3D printed multiple unit particle system (MUPS) containing metoprolol succinate

This study presents the development and characterisation of dual extrusion 3D printed multiple unit particle system (MUPS) tablets incorporating metoprolol succinate. Pharmaceutical-grade filaments were prepared via hot-melt extrusion, comprising a drug loaded sustained release formulation of Eudragit® RL PO, and a rapidly disintegrating tablet shell formulation based on Kollicoat® IR. The use of fused filament fabrication enabled the integration of drug-loaded cylindrical particles within the tablet shell. Comprehensive morphological and structural analyses, including scanning electron microscopy, X-ray micro-computed tomography, and digital microscopy, confirmed uniform particle geometry and distribution. The manufactured tablets met European Pharmacopoeia (Ph. Eur.) specifications for mass uniformity. Disintegration testing demonstrated complete disintegration of the tablet shell within 15 min. X-ray powder diffraction indicated the active pharmaceutical ingredient (API) was present in an amorphous state post-processing. High-performance liquid chromatography analysis revealed thermal degradation during 3D printing, with a reduction in API content from 97.8 % in the extruded filament to 65.9 % in the printed MUPS tablets. A linear correlation between the number of printed particle layers and the final drug content was shown, supporting the concept of dose individualisation. In vitro dissolution testing showed that 80 % of the incorporated API was released within 105 to 150 min. The findings confirm the feasibility of producing API-3D-MUPS tablets using pharmaceutical-grade materials, while also identifying critical product defects, formulation and process parameters such as thermal instability of the API or particle agglomeration - that require further optimisation of formulation and process parameters to enable broader application in personalised drug delivery.