Accurate low-temperature direct granule extrusion 3D printing of personalised paediatric minitablets

Medicine individualisation remains constrained by the limited availability of age-appropriate strengths and by extemporaneous practices that can compromise dose consistency. Direct extrusion 3D printing offers an alternative manufacturing method for personalised medicine, without introducing solvents, complex preparation, or post-processing that challenge the adoption in pharmacy. However, achieving uniform weight and drug content in small objects (e.g., paediatric-friendly minitablets) and lowering the preparation temperature remain challenges for direct extrusion-based 3D printing technologies. In this work, we introduce a facile low-temperature direct granules extrusion 3D printing strategy to manufacture carvedilol minitablets, starting from carvedilol powder or crushed licensed tablets as starting materials, using a high-precision pharmaceutical-grade 3D printer. Methacrylate-based polymers, polyethylene glycol, and glyceryl monostearate were used to enable extrusion at 70-75°C. When the 3D printer was challenged with minute-dimensional designs, it was possible to manufacture batches of minitablets up to 2 mm in diameter with 0.8 mm in thickness. The lowest minitablet weight variation was 1.48%, achieved with an optimal diameter of 3.6 mm and a thickness of 1.6 mm; this was also reflected in the drug content uniformity (within ± 5%). The batches also met British Pharmacopoeia requirements for dissolution (>80% in 45 min). These findings extend direct extrusion 3D printing to a viable manufacturing platform for accurate, low-dose small solid units, such as minitablets. By coupling a GMP-compliant 3D printer with a simplified preparation workflow, this work provides a realistic blueprint for integrating direct extrusion-enabled personalised minitablets into hospital pharmacy and point-of-care settings.