Solving Medical Device problems using

IR Microscopy

Visible Microscopy

Part 3: Application to Medical Device issues

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orba

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1000 1500 2000 2500 3000 3500 Wavenumbers (cm-1)

Silicone Lubricated Gasket

Less Silicone After Surface Scraped

No Silicone After Acetone Wash:Silicate-filled rubber polymer

ATR Spectra of Surface of IR-Opaque Rubber

2.3mm x 3.0mm Photos of an Insulin Needle Point

The Technology of a Needle Point

What can we learn with a fast analysis?

420μ x 550μ Photos of Needle’s three cut planes

The “subtle” cut

IR-PLAN 550μ X 420μ FOV of Point and Enhanced Image

Raw Image Obtained

Digital Enhanced Image

A “Metal Burr” is visibleon this needle point.

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W avenum ber s ( cm - 1)

Infrared Microscopy Provides Chemical Identification that showsGelled Lubricant is used on Hypodermic Needles

3.0mm x 2.3mm

550μ X 420μ

390μ x 300μ

Gel is Silicone

8.5mm X 11.2mm

Hoop Stress cracking

Polyetherimide (PEI) Stopcock Outerbody resists splitting caused by fatty Feeding Liquids but costs more than Polycarbonate (PC) (which is cracked by combination of fats and stress). Stopcock InnerBody is pressed into Outerbody and this strong PEI polymer can still crack if it can’t stretch enough under this “Hoop Stress”tensile load (vs PC which is very stiff but also very TOUGH/RUBBERY).

Engineering Resins: ESCR vs “Hoop Stress Failures”

PET Barrels That Failed At GateA “Cold Slug” in an Injection Molding “Gate”

can initiate breakage at unacceptably low force

Gate A Gate B Ridge/Valley

Cold Slugs

Blade Striations

Devices broke due to “Cold Slug” in Injection Molding Gate

Identification of PET Barrel SkirtContaminant by Micro-FTIR

Smudges on PET at Tip Insert of Barrels

Parting Line

Pre-Extracted Cellulose on PET Skirt Same Area of PET Skirt After Wiping

Streaks where Greasewas removed

Cellulose

Grease aboutto be removed

PET Barrel Skirt Bloom removed for analysis

5 .S ilic o n e B B L L u b e A T R ,B ra d m o n sK im w ip e d B lo o m in P E T B B L s k irt,G riffith ,R E F L 3 2P E T B B L s k irt g re a s e ,K im Wip e d & M C d ,C a s tro ,R E F L 3 2 ,2 /2 7 /0 91 2 0 a 2 2 0 9 ,M IC R ,C E L L U L O S E ,A C C U WIP E /A L ,2 /2 4 4

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Silicone

Cellulose

Grease Found Previously

Grease Found Recently

PET Barrel Skirt Contaminant is Same as Found previouslyThe Difference Seen below is Cellulose from the Kimwipe.

The Grease is an Acid (1712 cm-1) and an Ester (1737 cm-1).