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
(T3) and thyroxine (T4) 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) printing is a potential solution to enable the
dual deposition of T3 and T4 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 T3 and T4. Dose adjustments were achieved by printing solutions
adjacent to each other, enabling therapeutic T3 (15–50 μg) and T4 dosages (60–180 μg) to be successfully printed.
Excellent linearity was observed between the theoretical and measured dose for both T3 and T4 (R2 = 0.982 and 0.985, respectively) by changing the length
of the print objective (Y-value). Rapid disintegration of the ODFs was achieved (< 45 seconds). As such, this study for the first time demonstrates the ability to produce personalised dose
combinations by TIJ printing T3 and
T4 onto the same substrate for oral
administration.
