One ink for two processes: exploiting rheology to accelerate 3D-printed chewable tablet manufacturing

Personalised medicines are increasingly required in paediatric and hospital pharmacy practice, where licensed preparations may not be suitable. Semi-solid extrusion three-dimensional printing (SSE-3DP) enables the production of these patient-specific dosage forms, especially in chewable tablets. However, its layer-by-layer fabrication may limit manufacturing speed and routine implementation in time-pressured hospital pharmacy workflows. This study manufactured theophylline-loaded chewable gummy tablets via two routes: conventional SSE-3DP and template-based ink deposition (TID), using an identical printer and without pharmaceutical ink reformulation. The ink was printed directly at a low temperature to produce cylindrical 3DP tablets, whereas TID extruded at a higher temperature into customised pyramidal template cavities. Rheological assessment of the ink under two processing conditions showed that temperature-dependent viscosity behaviour underpinned the distinct manufacturing routes. Following process optimisation, TID shortened the deposition time for gummy tablets to 2-6 s/unit, 7-fold faster than 3DP (14-42 s/unit). When pre-and post-processing were included, total batch completion time per unit was halved. TID tablets met pharmacopeial requirements for weight and content uniformity, showing comparability to 3DP. Distinct drug release profiles were observed for both production methods. Gummy tablets from TID remained physicochemically stable for up to 28 days at 5°C and 25 °C. However, the differing thermal and post-processing solidification of the two routes may have resulted in distinct drug-release profiles. Overall, this work extends the functionality of the 3D printer and demonstrates a practical strategy for converting the SSE-3DP process into a rapid dispensing workflow for small-batch personalised gummy medicines in hospital pharmacies and point-of-care settings.