A team of scientists is working on a way to reduce the amount
of pharmaceutical pollution in our water systems by making commonly
used drugs biodegradable without impacting their effectiveness as
The researchers believe their idea for redesigning pharmaceutical compounds so they are more biodegradable might help protect water resources in a sustainable
Worldwide, water systems are gradually showing increasing
contamination by micro-pollutants – including pharmaceuticals – that
have the potential to harm fish and other aquatic creatures.
While the concentrations of such pollutants are fairly low, they are
high enough to cause concern, and recent research shows advanced
treatment of effluent may not go far enough to solve the problem in a
For these reasons, a team led by Klaus Kümmerer of
Leuphana University of Lüneburg in Germany decided to tackle the
problem from the other end – redesign commonly used drugs so they
biodegrade once they reach the environment.
In a paper published in the journal Environmental Science &
Technology, the researchers describe a method based on ultraviolet light
that they tested on propranolol – a beta-blocker used to treat high
Method based on ultraviolet light
The researchers got the idea from a method that is used to remove
pollutants from wastewater. Ultraviolet light can break down some
compounds into more biodegradable products. Perhaps the same approach
could be used to make compounds biodegradable in the first place.
The team chose to test the method on propranolol because it is a
commonly used drug that does not biodegrade when it reaches wastewater,
and in the concentrations found there, it is toxic to some aquatic
species when they are continually exposed to it.
In their paper, the researchers describe how they dissolved the
drug in pure water and exposed it to ultraviolet light for around 4
hours. This produced 16 breakdown products that they then incubated
with effluent from a sewage treatment plant to test their
biodegradability, which they did by measuring how much oxygen and
organic carbon the microbes consumed over time.
They found that the most biodegradable derivatives were the ones
that underwent changes that opened up their ring-like structure,
allowing the microbes greater access to digest them.
At least one of the derivatives – a compound called 4-hydroxypropranolol – was 23% biodegraded into inorganic molecules such
as carbon dioxide and water within a month.
And nearly half of the derivatives were at least partially
biodegraded into other inorganic compounds predicted to be low in
toxicity, the researchers note.
Using a range of techniques, the researchers found that 4-hydroxypropranolol may have drug properties similar to propranolol – something that had already been suggested in an animal study that
compared the two drugs.
A ‘truly sustainable’ way to protect water resources
While the work is still at the proof-of-principle stage, the team
believes the method could be extended to look for biodegradable
alternatives for a range of pharmaceutical products, including those
used in cosmetics and personal care. They conclude:
“Application of such approaches in turn might contribute
to the protection of water resources in a truly sustainable
Susan D. Richardson, an environmental chemistry researcher at the
University of South Carolina who was not involved in the work, says the team now faces a number of hurdles. These include testing
whether the derivatives are toxic to living organisms, and whether
water treatment such as chlorination changes the compounds.
But, if the researchers clear these hurdles, she says their
technique “could be a revolutionary way to lower our load of drugs to
Meanwhile, Medical News Today recently learned that
scientists have developed a more practical and efficient way of extracting venom from deadly box
jellyfish as a source of ingredients for new drugs. The method is an
example of how the study of venom, which has traditionally been
confined to understanding its effect as a toxin and developing
antidotes, is moving into drug development.
Written by Catharine Paddock PhD
Copyright: Medical News Today
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