Viscoelastic properties of polymer mixtures containing micro-ribbons and microfibres for the 3D printing of pharmaceutical dosage forms by fused deposition modelling

OBJECTIVES: To match the disintegration time of conventional oral films with 3D printed fast-dissolving oral films (FDFs), micro-composites have been used in the formulation. However, in certain cases the 3D-printer failed to produce desired films. METHODS: The viscoelastic properties were evaluated for polyvinyl alcohol and polyvinylpyrrolidone filaments containing chitosan micro-ribbons and cellulose microfibres as micro-composites with the hypothesis that intermittent nozzle blockage was the mechanism responsible for the observed printing failures. KEY FINDINGS: Domination of loss modulus over storage modulus was observed for successful printing. Micro-composites improved the viscoelastic properties of filaments including filaments that failed to print. The novelty of this research was that poor viscoelastic properties could not be accounted for the failure of FDF 3D printing for formulations with high micro-composite contents. Filaments of these formulations exhibited rough surfaces with visible aggregates. These observations suggested intermittent nozzle blockage by aggregated micro-composites could have been the cause of 3D printing failure. This hypothesis was supported by successful printing when printer nozzle diameter increased. CONCLUSIONS: The domination of loss modulus over storage modulus was essential for filaments to achieve successful FDF 3D printing. However, micro-composites at high concentrations in the formulation may induced nozzle blockage leading to printing failures.