3D Printing MicroFactory

Prasad, Elke and Robertson, John and Halbert, Gavin W. (2023) 3D Printing MicroFactory. In: CMAC Summer School, 2023-06-12 - 2023-06-16.

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3D printing (3DP) of pharmaceutical formulations via commercially available FDM printers has gained interest in recent years, enabling personalisation of medicines. It also facilitates advanced control of the micro-structure of the tablet core, permitting fine tuning of product release characteristics with a single formulation. In addition, the technology also offers a platform for dose escalation studies employing a single formulation and single manufacturing step. FDM printers utilise filament feedstock material of specific diameter, which is conveyed by a drive gear, molten in the hot end and extruded via the nozzle of the printer. Suitable mechanical properties of the filament and physical properties of the formulation are paramount in this process. Print failure can be associated with (brittle) filament breaking in the drive gear or soft (ductile) filaments buckling in the drive gear or hot end [1, 2, 3]. The formulation space for pharmaceutical additive manufacturing is therefore very limited, since most immediate release polymers are very brittle. In this study we present a novel, filament free FDM 3D printing system (Intellectual Property Office UK, patent application number 2101534.2), overcoming limitations of unsuitable filament properties and opening up the pharmaceutical formulation space in FDM of pharmaceutical oral solid dose forms. Prasad et al reported on a 30% w/w Paracetamol (PCM) - Affinisolâ„¢ 15 LV (hydroxypropyl methylcellulose, HPMC) formulation, not printable on a conventional FDM printer [1]. This formulation was processed on the filament free FDM printer to successfully print oral solid dose forms (OSDs). In initial rheological screening tests, process conditions for initial printing trials were identified. The operating space of the printer and slicer settings in this process were investigated as well as the uniformity of mass and dimensions of printed OSDs. A relationship of Slicer Infill percentage (microstructure) and tablet core weight was also assessed, demonstrating the ability to create patient centred dose forms. Material reconciliation showed good traceability of material during the manufacturing process. This study demonstrates how an integrated HME-3DP opens up the pharmaceutical formulation space for additive manufacturing, allowing for a wider range of pharmaceutically approved polymers (and formulations) employed in additive manufacturing and personalisation of dose forms.