relatively effective regulatory systems, the
proportion of medicines that are fakes is
probably less than 1 percent, still a staggering figure considering that more than
a billion pills are sold in the United States
each year. In countries with less secure
supply chains, the problem is worse.
In Cambodia, for instance, a survey
of intestinal-parasite drugs found that
more than 4 percent were counterfeit,
researchers reported last year in
Tropical Medicine & International Health. An
investigation reported in 2008 that half
of malaria drugs collected from parts of
Southeast Asia were counterfeit.
When medications contain little to
none of the active ingredient, the consequences can be severe. In February 2005,
for example, a 23-year-old man arrived
at a hospital in Myanmar infected with
the malaria parasite. He received pills
thought to contain artesunate, the treatment of choice. By the third night he was
in a coma and his kidneys had failed; he
died soon thereafter.
Infectious-disease specialist Paul
Newton of the University of Oxford, who
works out of Mahosot Hospital in Laos,
and colleagues were called on to figure
out what had happened. Analyzing the
medication using a technique known as
DART-MS revealed that the man’s pills
were counterfeit, mostly containing the
pain reliever acetaminophen.
Mass spectrometry
Molecular exposure
Researchers have many ways to determine a material’s constituents. some, such as mass spectrometry and Raman spectroscopy,
have been around for decades. new tweaks on the classic methods are providing faster and easier ways to spot counterfeit drugs.
Intensity
a vaporized
compound is
electrically
charged.
the charged molecules are turned
into a high-speed
stream.
a magnetic field bends this
stream, the heavier particles
straying toward the outside of
the bend, and the lighter ones
staying toward the inside.
the particles are analyzed and
a readout is given in the form
of a spectrum. Comparison with
reference spectra reveals what
is in the compound tested.
Mass
Raman spectroscopy
Intensity
t. dubÉ
light is shined on a
sample, with little or no
preparation required.
some of the light hits
the sample’s molecules,
causing them to vibrate.
the re-emitted light differs in
color, a change in wavelength
called the “Raman shift.”
Reflected light is analyzed to
produce a spectrum that can be
used to identify the substance.
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June 18, 2011 | SCIENCE NEWS | 23
