Extrusion-based three-dimensional (3D) printing has emerged as a promising platform for delivering personalised solid oral dosage forms however, its broader adoption remains constrained by limited throughput, variable dose uniformity, and inconsistent print reliability. This project seeks to optimise extrusion performance through coordinated advances in feedstock formulation and extrusion control. By integrating materials science, pharmaceutical engineering, and process analytics, the study aims to define robust, scalable strategies that enhance extrudability while meeting stringent quality requirements.
The first objective is to engineer hot-melt extrusion (HME) filaments and semi-solid extrusion (SSE) pastes with rheological properties tailored for continuous, stable deposition. Formulation work will focus on polymer-based systems, active pharmaceutical ingredient (API) particle-size control, and the application of flow modifiers to achieve predictable shear-thinning behaviour, rapid structural recovery, and homogeneous API distribution. Vital characteristics for a formulation to be extruded cleanly and then hold its shape once deposited. Physicochemical characterisation using techniques including HPLC, DSC, TGA, XRPD, and FTIR will facilitate formulation understanding and provides the evidence base for future developments.
The second objective targets hardware-driven improvements in extrusion consistency. Optimised nozzle geometries, enhanced thermal management, and the integration of pressure, torque, and temperature dynamics will be evaluated to minimise clogging, thermal gradients, and flow variability. Within this, a structured design-of-experiments (DOE) framework will link formulation attributes and hardware parameters to critical quality attributes, including dose uniformity, tablet geometry, mechanical strength, and dissolution performance. The anticipated practical outcomes include a validated operating space enabling higher throughput and enhanced quality of both feed material and print outcomes. In addition, practical guidelines for feedstock preparation and process control will have potential to inform future policy.
This research will provide the scientific and engineering foundations necessary to advance extrusion-based 3D printing toward reliable, GMP-compatible manufacturing of personalised oral medicines.
Curti, C., Kirby, D.J. and Russell, C.A., 2020. Current formulation approaches in design and development of solid oral dosage forms through three-dimensional printing. Progress in Additive Manufacturing, 5(2), pp.111-123.
Curti, C., Kirby, D.J. and Russell, C.A., 2024. Systematic screening of photopolymer resins for stereolithography (SLA) 3D printing of solid oral dosage forms: Investigation of formulation factors on printability outcomes. International Journal of Pharmaceutics, 653, p.123862.
