SPID® explained: how 3D screen printing builds a tablet layer by layer

A familiar principle, applied anew

SPID® stands for “Screen Printed Innovative Drug”. Behind it is a process that brings two familiar worlds together: flatbed screen printing, as known from graphics and electronics manufacturing, and the layer-by-layer build of additive manufacturing. Instead of compressing a powder blend in a die, the tablet is built from a semi-solid paste that contains the active ingredient and standard excipients.

The sequence is quickly described: a thin layer of paste is applied through a screen onto a carrier plate. The plate then moves to a drying station and back to printing until the desired height is reached. According to Adare Pharma Solutions, which offers the technology together with Laxxon at clinical scale, each layer is between 10 and 150 micrometres thick.

No heat

A key difference from many other 3D printing processes is temperature. Fused deposition processes work with heated nozzles, others with lasers. Both limit the choice of active ingredients, because not every substance tolerates heat. Laxxon put it this way to the trade magazine 3D ADEPT: “Unlike 3D printing, our technology does not rely on lasers nor a heated nozzle to administer printed products.” Adare accordingly describes SPID® as a cold process.

Shape and inner structure can be chosen freely

Because each layer is defined by its own screen, both the outer shape and the inner structure of a tablet can be designed. Switching between screens and paste formulations produces complex layer structures in which active ingredients are not spread evenly but placed in specific regions. This is what makes it possible to control release profiles.

That printed tablets can meet pharmaceutical requirements was shown by a study published in the International Journal of Pharmaceutics in 2021, with researchers from Laxxon Medical among the authors (Moldenhauer et al.). Tablets of different shapes and sizes were printed from a delayed-release paracetamol paste. Size and mass were uniform, and breaking strength and friability compared favourably with conventionally made tablets. The authors see potential for mass production of more complex oral dosage forms with high reproducibility.

From the lab to series production

For industrialisation, it is crucial that the same principle holds from the smallest batch to large-scale production. According to the company, the technology suits both small batches for preclinical and clinical studies and industrial manufacturing; in 2023 the company cited a capacity of up to 560 million units per year.Freigabe prüfenKapazitätsangabe abgleichen: hier 560 Mio. Einheiten/Jahr (2023), auf „Properties“ 1,5 Mio. Einheiten/Tag

For the clinical phase, Adare offers cGMP manufacturing at its site in Pessano near Milan. Commercial-scale equipment is to follow there at a later date. Laxxon’s research and development is based in Jena.