Technology thinks tiny to deliver drugs in cancer war ; Research in Cardiff is creating targeted designer molecules

WELSH researchers are working on developing ultra-small ‘nanoparticles’ to tackle breast and prostate cancers more effectively.

It could allow higher doses of more toxic drugs to be used without fear that widespread damage to tissues will be caused.

The work is being carried out by the recently established Centre for Polymer Therapeutics established within the Welsh school of Pharmacy at Cardiff under the direction of Professor Ruth Duncan.

It specialises in the use of so-called designer molecules made up from polymers which are chemicals constructed of long chains of molecules.

The active drug is carried within the nanoparticle.

The field of bionanotechnology is an extremely young one with a very rich potential for fighting various forms of cancer.

A team in Nottingham doing similar research is looking at ways of fighting brain tumours.

By using nanotechnology, engineering at a molecular level, the scientists based in Cardiff have been able to attach water soluble polymers to drug molecules.

This temporarily makes the drug inactive so it can enter the body without doing any harm to sites other than where the cancer exists.

When the drug reaches the site of the cancer it engulfs cancer cells and this process breaks down the polymer releasing the anti- cancer drug.

The new drug delivery system means the drugs can also circulate longer in the patient’s body with fewer of the side effects associated with many modern anti-cancer treatments.

Several of the polymer- drug anti-cancer combinations currently undergoing clinical trials are based on compounds closely related to those used for soft contact lenses.

Another advantage of polymer drug combinations relates to the way in which the large molecules carrying drugs are effectively trapped within the leaky tissues of growing tumours because of their size.

This means they are retained to deliver the maximum effectiveness at the site where they are most needed instead of simply escaping back into the bloodstream causing side effects.

The process can also mean that higher doses of an effective cancer treatment can be administered without concerns about toxic effects on the patient.

Other promising areas of research include designing multi- branched polymer molecules called dendrimers which can even be tailored to deliver drugs to patients with certain allergies.

Drug molecules can be hidden within the core of the dendrimer or attached to its various branches depending on the sensibilities of the patient.

Early attempts at using the polymer particles as drug delivery systems failed because they were only capable of holding on to very small amounts of drug compound and often did not hold on to it for very long.

But designs are improving all the time and at the moment the particles are under test using less toxic anti-inflammatory drugs also given to cancer patients.

It is hoped that soon their reliability can be proved so cancer drugs can be given directly in this way.