Printing T and T oral drug combinations as a novel strategy for hypothyroidism.

Hypothyroidism is a chronic and debilitating disease that is estimated to affect 3% of the general population. Clinical experience has highlighted the synergistic value of combining triiodothyronine (T) and thyroxine (T) for persistent or recurrent symptoms. However, thus far a platform that enables the simultaneous and independent dosing of more than one drug for oral administration has not been developed. Thermal inkjet (TIJ) 2D printing is a potential solution to enable the dual deposition of T and T onto orodispersible films (ODFs) for therapy personalisation. In this study, a two-cartridge TIJ printer was modified such that it could print separate solutions of T and T. Dose adjustments were achieved by printing solutions adjacent to each other, enabling therapeutic T (15-50 μg) and T dosages (60-180 μg) to be successfully printed. Excellent linearity was observed between the theoretical and measured dose for both T and T (R = 0.982 and 0.985, respectively) by changing the length of the print objective (Y-value). Rapid disintegration of the ODFs was achieved (<45 s). As such, this study for the first time demonstrates the ability to produce personalised dose combinations by TIJ printing T and T onto the same substrate for oral administration.