Scientists have discovered that a promising new anticancer medicine currently in development
could be made from unknown dangerous compounds. This discovery could overturn over 60
years of chemistry and almost 100 publications.
Published in Dalton Transactions, the work from King’s College London and Jagannath
University in Bangladesh found that the process of making gold-based cisplatin mimics, a newly
patented class of anticancer treatment, did not create a pure product as originally believed.
Instead, the scientists found it is made from a mixture of potentially dangerous isomers,
molecules which have the same elemental make up but a different structure.
This can cause a drug to have potentially negative effects. In the 1960s, the isomer of the
morning sickness medicine thalidomide, caused thousands of children to be born with
abnormalities, subsequently tightening pharmaceutical legislation.
As it stands, the compound is not currently in use and not in clinical trials.
These gold-based cisplatin mimics are part of the gold(III) dithiocarbamate family of chemical
compounds and act like cisplatin, an anticancer drug currently being used based around a
single platinum particle. However, this new gold-based chemotherapy treatment promises less
of the negative side effects associated with cancer treatment, such as tiredness and hair loss.
Papers dating from 1964 have suggested that gold(III) dithiocarbamates could be made easily as
a single compound, after the constituent molecules were combined. Subsequently, much of
the research done on these compounds have been based on this synthesis.
However, through careful analysis of the products formed in this reaction, the team discovered
it actually produced a mixture of isomeric compounds, instead of a pure single one. This
challenges over 60 years of established scientific wisdom and literature.
While in some cases the main component was a positively charged cisplatin mimic, as opposed
to neutral one outlined in previous studies, in all experiments it was impossible to obtain a
‘pure’ compound in an environment similar to the human body.
This poses major concerns about the use of the medicine in human subjects, as it may actually
be made from compounds which have not been medically tested.
Dr David Pugh, a Lecturer in Inorganic Chemistry, King’s College London and lead author of the
study, said, “We were not expecting this result at all. When we first started making these
compounds, we trusted that the literature was accurate – but we now know that this is not the
case.
“This means the toxicity of these compounds has not been rigorously tested, and that by using
these drugs, we’re potentially stepping into dangerous, unknown territory. This demands a
serious re-think in how we use them before they potentially hit the market.”
In light of their work into the synthesis of dithiocarbamate supported gold compounds, the
research team is now urging further studies into the mixture, suggesting more work needs to be
done to establish its safety
Journal
Dalton Transactions