Study Shows High Accuracy of Medicinal 3D Printing

A study led by University of Cambridge Post-Doctoral Researcher Dr. Daniel Markl and Chemical Engineering professor Dr. Axel Zeitler demonstrated the viability of 3D printing technology in structuring and printing active pharmaceutical ingredient (API) formulations.

Over the past few years, researchers and institutions have been actively looking into the usability of 3D printers in creating medicine. We have seen companies such as Aprecia Pharmaceuticals, which was approved by the US Food and Drug Administration (FDA) to produce and distribute SPRITAM levetiracetem tablets manufactured using enterprise-grade 3D printers.

At the time, Aprecia CEO Don Wetherhold expressed his optimism towards the utilization of 3D printing technology in the field of medicinal manufacturing and stated:

“By combining 3D printing technology with a highly-prescribed epilepsy treatment, SPRITAM is designed to fill a need for patients who struggle with their current medication experience.”

Recently, six researchers tested the accuracy of 3D printing technology in creating medicine.

“Given the unique ability to print extremely well defined structures, and the role these structures play in the design of the dosage form, it is clear that the microstructure will play a central role to define the drug release characteristics, and hence performance, for a 3D printed dosage form,” the study explains.

X-ray computed microtomography [Image: HZDR]

The high resolution of XμCT allows researchers to evaluate and analyze details that can’t be collected with other scanning methods. With XμCT and TPI, another technology designed to provide 3D images of an object’s interior, the team of researchers were able to obtain detailed structural data of API formulations tested in the study.

Figure 4 in the study: Visualisation of XμCT data of sample S03 (cylindrical PVA shell filled with CBZ). (a) 3D visualisation of XμCT data. (b, c) x-y cross-section images from the positions as denoted in (a).

To eliminate any potential variables that may affect the evaluation of 3D printed dosage forms, researchers performed the experiment with two solutions: polyvinyl alcohol (PVA) and polylactic acid (PLA), with both materials supplied by Innofil3D. PVA and PLA-based 3D printed drugs were then examined by XμCT and TPI.

After examining XμCT and TPI scans of the two types of 3D printed dosage forms, researchers discovered that there exists a major difference in porosity between PVA and PLA prints. PVA prints showed an average porosity of 5.5% and PLA prints demonstrated 0.2%, a porosity rate 27.5% smaller than PVA prints.

The difference in porosity doesn’t necessarily represent the viability and efficiency of the dosage forms tested in the study. Researchers aimed to show that 3D prints of dosage forms can deviate depending on variables, such as the designed model and solution used, and that the accuracy 3D printing technology can lead to the creation of commercially successful medicine.

Figure 5 from the study: Analysis of pore structure of (a,b,c) PLA and (d,e,f) PVA shells on the basis of XμCT data. (b) and (e) illustrates only the pores, where a colour depending on the pore length was assigned to each connected pore. (c) and (f) are y-z cross-section images of the PLA and PVA shell, respectively. The colour map is valid for all subfigures.

The research paper, entitled “Analysis of 3D Prints by X-ray Computed Microtomography and Terahertz Pulsed Imaging”, reads:

“The 3D printer can reproduce specific structures very accurately, whereas the 3D prints can deviate from the designed model. The microstructural information extracted by XμCT and TPI will assist to gain a better understanding about the performance of 3D printed dosage forms.”

Continuing in the full conclusion, “3D printed compartmentalised formulations allow tailoring the in-vitro release profile of the respective drugs…  In conclusion this work shows that 3D printing can be used to produce patient-centred combinatorial drug products with different release and dosing properties depending on the patients’ need.”

The study’s authors include Daniel Markl and J. Axel Zeitler from the Department of Chemical Engineering and Biotechnology, University of Cambridge; and Cecilie Rasch, Maria Høtoft Michaelsen, Anette Müllertz, Jukka Rantanen, Thomas Rades, and Johan Bøtker from the Department of Pharmacy, University of Copenhagen. Discuss in the 3D Printed Pharmaceuticals forum at 3DPB.com.