Technical pen-based printhead for high-precision microdosing of personalized therapies.

Additive manufacturing offers unprecedented opportunities for personalized medicine, but most pharmaceutical printing platforms are optimized for milligram-range doses, limiting their suitability for microdosing. This work introduces a novel liquid deposition approach using a modified technical pen integrated into a pharmaceutical printer. The gravity-driven mechanism enabled precise microscale dispensing without external thermal, pneumatic, or electrical inputs, which have been associated with molecular stress in other printing technologies. Desmopressin, a potent synthetic hormone indicated for diabetes insipidus and requiring ultra-low doses, was selected as a model compound. Oral films (2 × 4 cm) containing therapeutically relevant doses (33-134 µg) were produced by depositing up to four layers of pharmaceutical ink. A custom-developed software interface allowed precise control of key process parameters, supporting reproducibility and automated workflows. The system achieved ~ 100% dose accuracy, with a strong correlation between drug content and layer number. Films exhibited rapid disintegration and immediate release. Stability testing showed no drug degradation over one month. Unlike more complex printing platforms, the technical printhead architecture offered straightforward manipulation and rapid setup. Given the constant ink flow rate and low, consistent, deposition volumes, only 1 mL of formulation is sufficient to produce up to 238 single-layer 2 × 4 cm films. These findings position the technical pen-based printhead as a promising, precise, and cost-effective addition to the additive manufacturing landscape, with strong potential for low-dose personalized pharmaceutical applications, including biologics. Moreover, its performance underscores the potential for further optimization and broader application.