APR January/February 2022 - 52

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SPECTROSCOPY
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Detection of Compounds Found in an
Unapproved Dermal Filler Using Fourier Transform
Infrared (FT-IR) and Surface Enhanced Raman
Scattering (SERS) Spectroscopy
Martin M. Kimani, PhD, Adam Lanzarotta, PhD,
Michael D. Thatcher, and JaCinta S. Batson, MS
US Food and Drug Administration, Office of Regulatory Affairs, Office of Regulatory Sciences,
Forensic Chemistry Center, Cincinnati, OH
The use of injectable materials for soft-tissue augmentation has been
increasing globally.1
The US FDA has approved materials such as calcium
hydroxylapatite, poly-L-lactic acid (PLLA), polymethylmethacrylate
beads (PMMA microspheres) and cross-linked hyaluronic acid (HA)
as injectable dermal fillers. Cross-linked HA, calcium hydroxylapatite
and PLLA are absorbable temporary materials that last in the body
for approximately 6 to 24 months, whereas PMMA microspheres are
comprised of a non-biodegradable man-made polymer.2,3
The increased demand for dermal fillers has resulted in the emergence
of unapproved products that are flooding the US supply chain and
could result in adverse and/or irreversible effects in consumers.4
The
US FDA's Forensic Chemistry Center (FCC) has received hundreds of
unapproved injectable dermal fillers through the course of criminal
investigations over the last 10 years. Although this laboratory has
encountered products that contain each of the compounds listed
above, the most frequently received unapproved products are
labeled to contain HA, some of which made their way through US
ports of entry such as international mail facilities (IMFs) and express
courier hubs (ECHs).5
Lidocaine may be present in both approved HAcontaining
dermal fillers as an allowed anesthetic to decrease pain or
discomfort during the procedure.2
Dermal fillers labeled to contain
or found to contain polydimethylsiloxane/silicone (PDMS) are not
FDA-approved2
for any aesthetic procedures due to the risk of longterm
pain, infection, permanent disfigurement, embolism, stroke and
death.3,6-8
Injectable silicone is currently only approved by the FDA for
intraocular ophthalmic use.6 Consequently, there is a need for rapid
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detection of HA, PMMA, PLLA, calcium hydroxylapatite, lidocaine and
adulterants (such as PDMS in unapproved dermal fillers). There is a
need to conduct these analyses at remote sampling sites such as IMFs
and ECHs so that suspect products can be examined on-site without
requiring off-site laboratory analysis for regulatory action to be taken.
The presented work describes the analysis of unapproved dermal filler
gels labeled to contain HA and lidocaine obtained from an adjudicated
criminal case using Fourier transform infrared spectroscopy (FT-IR) and
surface enhanced Raman scattering spectroscopy (SERS). Results from
the FT-IR analysis of neat and oven-dried gels to detect HA, lidocaine
and PDMS will be presented. The development and implementation
of simple SERS and FT-IR micro-extraction methods for identification
of lidocaine and other adulterants in these products will also be
discussed.
Materials and Methods
The following reference standards, reagents and materials were used:
lidocaine HCl, lidocaine free base, sodium hyaluronate, methanol
(HPLC grade) and potassium bromide, poly-L-lactic acid, poly(methyl
methacrylate), polydimethylsiloxane (PDMS), nylon plus glass 30mm
diameter, PTFE 0.20-μm and 0.45-μm pore size filters, calcium
hydroxylapatite, silver colloids, 3 mL luer-lock syringes. The following
equipment was used: electronic pipette; Vortex-2-Genie; Mettler
Toledo XS205 Semi-Micro balance.
APR January/February 2022

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