3D Printed Tablets Hold Promise for Tailor-Made Medicines

Researchers in the Basque country have used 3D printers to make starch-based tablets that could be used to customize medicines for individual patients.

The tailor-made tablets created from maize and potato starch could personalize drugs to meet the needs of each patient according to their genetics, gender, or constitution.

They could also generate age-appropriate doses for the young or elderly as an alternative to conventional pills with regular adult formulations.

In addition, the tablets offer the potential for alternative dosing systems such as flash delivery, in which fast-disintegrating tablets immediately dissolve on the tongue to rapidly release the required drug formulation.

A combination of starches from the different plant sources—normal or waxy maize or potato starch—tailored the release of non-soluble drugs to between 10 minutes and 6 hours, the researchers report in the International Journal of Pharmaceutics.

Combining different starches resulted in two-stage release systems that could have particular applications, said lead investigator Kizkitza González of the Engineering College of Gipuzkoa, University of the Basque Country in Donostia-San Sebastián, Spain.

“For example, in the case of an infection, in an initial stage using normal maize starch, a medicine could be released immediately to alleviate pain, and in a subsequent stage, with either of the other two types of starch, an antibiotic could be released more continuously,” she explained.

The team created tablets from waxy maize, normal maize, and potato starch with different shapes using semi-solid extrusion, otherwise known as direct ink writing.

Gels or pastes were inserted into a syringe before printing, and the starch-loaded tablets individually assessed as drug delivery systems.

The starch’s botanical origin affected its gelatinization temperature, and tablets made from the different sources each had different microporous structures, compression, and swelling behaviors.

Normal maize starch had a porous morphology that was not able to form a stable structure whereas for waxy maize and potato starches this was well defined, with both the latter able to maintain their integrity after being immersed in phosphate-buffered saline for sustained periods.

Normal maize starch resulted in instantaneous drug release, with full release within 10 minutes, whereas waxy maize starch and potato starch resulted in more continuous release that could take up to 6 hours.

Drug release properties were dependent on microstructure, degree of  porosity, the amylopectin/amylose ratio and the presence of other components in the starch as well as the ability to form an effective network structure.

Different tablet shapes—cylindrical or pyramidal—also had an impact on drug release kinetics.

Given the different swelling behavior and flash-release ability of normal maize starch, the team also tested a combination of normal maize starch with waxy maize or potato starches in a single loaded tablet and found this created a two-stage release process

Reporting in the journal, González and colleagues conclude that “the obtained starch-based 3D printed tablets showed promising properties in view of future personal drug release applications.”