Pharmaceutical scientist Gert Storm works on the
design, research and testing of targeted nanomedicines. These are tiny balls
that can be transported to the right place in the body, helping doctors to dose
medicine more efficiently and preventing the drug from damaging other parts of
the body. "A drug that combats kidney problems should not end up at the
lungs."
If you have a headache, you take paracetamol or
ibuprofen. After about twenty minutes, your headache will start to subside and
it will eventually disappear. But how does a painkiller know that the pain is
in your head? And can we control that?
Porous vessel
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| Professor G. Storm |
"A drug enters your bloodstream via an injection
or pill," explains biopharmacist Gert Storm. "Let's first make a
distinction between a drug and its active substance. The active substance, also
known as an active pharmaceutical ingredient (API), the pharmacologically
active drug molecule, is the substance that needs to cure us. The drug or
medicine is the entire drink, pill or injection."
"The interior of a blood vessel is lined with
cells that make the vessel wall almost entirely non-porous, but a local
infection can make the vessel lining a little bit more porous in that
area," says Storm. " However, the drug does not 'know' where to go
and only ends up at the right place in only low amounts because our heart pumps
blood through our body. Chances are small that the API will eventually end up
at the right place. And the substance also tends to leave the body quickly, in
urine for instance, so that we have often to start off with a high dosage that
is administered frequently.
More efficient dosing
Such intensive dosing schedules are especially
unfortunate for medicine as they can lead to severe side effects. So Storm and
his colleagues conduct research into Drug Targeting. "We want to guide the
drugs to the right 'address' in the body, thereby making high dosages redundant
and increasing the efficacy of the medicine without burdening the body parts
which do not need it," he explains.
" We are developing medicines that go straight to the source of the
problem, where they need to work." One way to do that is to exploit the
more porous vessel walls which are often present in diseased areas.
Exploding nanoballs
Storm explains that they work with tiny (‘nano’) balls
made of fats or polymers. "We put the API into the balls. There are
already fat globules present in our body and are therefore a natural way to
transport substances" he explains. "A nanoball will be able to go
through the porous vessel wall and is less likely to end up in urine than the
API itself"
Storm works at the UMC one day a week. "We work
with temperature-sensitive nanomedicines, which are globules that burst open at
a specific temperature and then completely release the drug in seconds. We
mainly use them to combat tumours. In an MRI scanner, we can identify the
precise location of a tumour. We then use ultrasound to heat the tumour to 42°C, which is exactly the temperature at
which the globules are triggered to burst open. The API is delivered at the
right place in the right way, and high dosages indusing side effects are therefore not needed. Other organs, which may
be susceptible to the substance, will not be damaged either, as the ultrasound
waves are really focussed on the tumour area only."
Full integration
