Laser vision A twist on Raman spectroscopy called SORS can see through drug blister packs
by recording signals offset from where a laser beam hits a sample. Two spectral peaks (marked
with dotted lines) signaling ibuprofen in a reference sample (top) are revealed by SORS (middle) but
obscured by interference from the blister pack when examined with conventional Raman (bottom).
Reference spectrum
Laser
in
Raman
signal
Relative intensity
Raman
signal Laser in
Conventional Raman
(with blister pack)
400
600
800 1000 1200 1400
Wavenumber (cm- 1)
1600 1800
mass spec technique on which DESI is
based, was quoted as calling DESI-MS
“the greatest thing since night baseball.”
A newer version of DESI, reported by
Cooks’ lab in 2006, dopes the stream of
solvent with additional molecules that
can grab onto ingredients of interest,
revealing their presence with much
greater sensitivity. Reporting in
Analytical Chemistry in 2007, Fernández and
colleagues found that “reactive DESI”
was 170 times more sensitive than DESI
at detecting artesunate in antimalarial
meds. In some fakes, the technique
also revealed a cheap and less effective
chemical relative of the real antimalarial
active ingredient.
“Reactive DESI is one of the stars,”
Fernández says. “It’s very dynamic. You
can use it to selectively detect certain
molecules and even quantify them. And
you can do it on the fly.”
The method also proved useful for
screening Tamiflu, fake versions of
which sold widely on the Internet dur-
ing recent flu outbreaks.
Tickled with light
While lack of active ingredients means
that a patient isn’t getting the expected
benefit, the wrong ingredients can result
in symptoms that make diagnosis difficult. And in some cases, wayward ingredients can be deadly.
In Singapore in 2008, 149 men were
admitted to hospitals with severe low
blood sugar; these men were not diabetic,
but seven went into comas and four subsequently died. The culprits were various
versions of fake sexual enhancement and
erectile dysfunction drugs contaminated
by glyburide, a powerful diabetes drug,
scientists reported in the New England
Journal of Medicine in 2009.
The embarrassment and high price
associated with erectile dysfunction
drugs such as Viagra and Cialis, known
as phosphodiesterase type 5 inhibitors
or PDE5Is, make them among the most
commonly purchased over the Internet,
a land rife with cons. Since Viagra hit the
market in 1998, it has also become one
of the most widely counterfeited drugs
in the developed world. From 2004 to
2008, 35.8 million fake Viagra tablets
were seized in Europe. In Japan, sales
of illicit PDE5Is are estimated at 2. 5
times larger than the market for genuine counterparts, researchers reported
last year in Environmental Health and
Preventive Medicine.
In another paper published last year,
in the International Journal of Clinical
Practice, researchers cited a laundry list
of other pharmaceuticals that have
turned up in fake erectile dysfunction
drugs, including acetaminophen; the
ovary-stimulating drug clomiphene;
fluoxetine, the active ingredient in Prozac;
and dipyrone, an anti-inflammatory used
by veterinarians to treat horses. Other
ingredients include lactose, talcum pow-
der and printer ink (used to paint the fake
little blue pills blue).
