Medical Design Briefs - August 2024 - 26

Personalized Medicine
Right: NIST researcher Thomas P. Forbes is working to ensure
3D drug printers work as designed. (Credit: R. Eskalis/NIST)
Left: Watch the video to see
the 3D printing process.
Q: In your journal article, you break
down the quality control process step by
step. Can you take us through that?
A: It starts with the delivery of the
printing ink to the remote location.
You need to confirm it hasn't degraded,
evaporated or been exposed to
unusual temperatures. You want to
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26
confirm it's still good. We used a technique called ultraviolet-visible (UV-Vis) spectroscopy.
There are now relatively inexpensive tabletop and even handheld UV-Vis
spectrometers on the market. They work by shining ultraviolet and visible light
through your sample. How the sample absorbs them tells you about its chemical
composition.
Next, we looked at how you can verify your printer is working correctly. Many commercial
printers have LEDs beneath the individual nozzles that print the ink for the
drugs. Every time the nozzle releases a drop of ink, it breaks the flow of light, which is
detected by a type of light detector known as a photodiode.
The photodiode will detect if the nozzle stops releasing liquid because you've run
out of ink. If there's a blockage in the nozzle or even a piece of dust causing irregularities
in the flow of ink drops, that will also be detected. In our tests, we found the LEDs
and photodiodes performed well.
Q: What about confirming that you've printed the correct amount of the drug?
A: That's tricky. You need a nondestructive way of confirming the correct dosage.
We are working on this right now. It's the next big step.
Q: What's the ultimate goal here?
A: We'd like to produce a series of voluntary protocols or recommendations for quality
control and measurement accuracy in 3D drug printing. We will likely work collaboratively
with other groups, such as American Society for Testing and Materials or United
States Pharmacopeia, to release these. If 3D drug printing becomes widely adopted, we
want to be ready to support both industry and regulatory agencies with a measurement
science foundation.
This article was written by Lawrence Goodman, NIST. For more information, contact
NIST at 301-975-2000, or visit www.nist.gov.
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Medical Design Briefs, August 2024

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Medical Design Briefs - August 2024

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