In this installment of our series showcasing the impact of the Snowwhite2 SLS 3D printer on scientific advancement, we’re focusing on the paper “The effects of recycling pharmaceutical formulations in laser powder bed fusion 3D printing – the influence of physical phenomena on printing performance“. We’ll kick things off by breaking down the study’s purpose and its key outcomes in plain language, ensuring everyone can grasp the significance of the research. Then, for those interested in the technical details, we’ll present the original abstract and any associated references.

Summary: 3D Printing Tablets and Powder Recycling

Laser powder bed fusion (LPBF) is a 3D printing technology that uses a laser to turn powder into solid objects, like medicine tablets. To make this process cheaper and more sustainable, scientists want to reuse the leftover powder.

In this study, researchers compared two different machines: the Sharebot SnowWhite2 and the Sintratec Kit SLS. They tested three different chemical mixtures to see if they could be recycled up to 10 times.

The Printer Comparison The study found a massive difference between the two printers:

  • Sharebot SnowWhite2: The tables produced are consistent, high-quality tablets, allowing the scientists to collect clear and reliable data.

  • Sintratec Kit: The tablets produced with this machine had “large and inconsistent variations.” The results changed so much between prints that the scientists couldn’t even use the data for their analysis.

The Recycling Results (using SnowWhite2) Using the data the researchers found that:

  • The first mixture (PVA-based) stayed perfect for 5 cycles.

  • The second mixture (acid-based) was very stable and lasted for 9 cycles.

  • The third mixture (copovidone) failed. The particles became too big, and the tablets became too light to be used.

    Fig. 1

The top row shows pictures of the top of the tablets printed by SnowWhite2 from left to right PVA, PVPVA and MAEA. The bottom row shows SEM pictures of the cross-section of those tablets in the same material order, highlighting the morphology in greater detail.

Main result

The main discovery is twofold. First, it proves that powder “ageing” is a real challenge in pharmaceutical 3D printing; reusing powder can change its physical properties (like particle size), which can eventually ruin the quality of the medicine.

Second, the study highlights that the choice of hardware is critical. The discovery shows that a professional-grade printer like the Sharebot SnowWhite2 provides the stability and precision needed for pharmaceutical applications, whereas more basic “kit” printers may produce inconsistent results that are not suitable for scientific or medical use.

Finally, they confirmed that even when the physical size of the powder changed, the chemical integrity of the drug remained safe (no degradation), which is great news for the future of 3D-printed medicine.

The effects of recycling pharmaceutical formulations in laser powder bed fusion 3D printing – the influence of physical phenomena on printing performance

Wessel Kooijman (a), Valerie R. Levine (b), Robbert J. Kok (a), Jonas Lindh (b), Julian Quodbach (a)
a) Division of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Universiteitsweg, 99 3584, CG, Utrecht, the Netherlands
b) Division of Nanotechnology and Functional Materials, Department of Material Science and Engineering, Uppsala University, Uppsala SE-751 03, Box 35, Sweden

Ref.: https://www.sciencedirect.com/science/article/pii/S2590156725000684

Abstract

Laser powder bed fusion is an attractive technology for 3D printing objects in a powder bed and has been explored for printing pharmaceutical dosage forms, such as tablets. Recycling of non-sintered residual powder is not well understood, but is critical to prevent economic losses and improve the sustainability of this technique. We investigated the recyclability of three pharmaceutical formulations in the context of laser powder bed fusion of tablets. Three formulations consisting of common pharmaceutical polymers and the model drug indomethacin have been investigated up to ten print cycles. For each print cycle, powder and tablet samples were collected and analyzed for ageing phenomena. Results showed that polyvinyl alcohol and methacrylic acid-ethyl acrylate copolymer-based formulations were recyclable without changes in critical quality attributes of printed dosage forms for 5 and 9 cycles, respectively. A copovidone-based formulation showed a gradual increase in particle size over 10 cycles, resulting in a gradual decrease in tablet weight. This formulation was considered non-recyclable under the conditions evaluated in this work. The observed ageing phenomena were mainly related to changes in particle size, powder cohesion, and glass transition temperature. It is shown that considering powder ageing during formulation development is critical for optimal print performance and further development of laser powder bed fusion for pharmaceutical applications.