Oscillatory system to deliver drugs

Future drug delivery devices could use microscopic chemical reactions to release medication at target areas in the body.

The technology could be the result of a five-year Newcastle University research project that will attempt to develop applications for oscillatory chemistry.

Oscillatory chemistry, first discovered in the 1950s, is more visually distinctive than most chemical reactions.

Scientists found that mixing certain compounds together will create rings that move in rhythmic wave patterns and oscillate back and forth between coloured states.

Katarina Novakovic, the leader of the Newcastle research, said that a couple of years ago it was discovered that oscillations could be instigated by subjecting a chemical reaction to a specific pH level or temperature.

The Newcastle researchers have re-demonstrated this with an oscillatory system that includes a palladium iodide catalyst, potassium iodide, oxygen, sodium acetate, methanol and phenylacetylene.

The team believes that such an oscillatory system could be chemically bonded onto a smart polymer gel and used for drug delivery devices.

Novakovic said that, ideally, the polymer would contract and release medicine when in the presence of a certain pH level in the body. She added that this would be helpful when trying to reach tumours, because those cells are known to decrease the pH level of their surrounding area.

‘When the device reaches the cells affecting local pH levels, its gel layer will start to contract and expand and release small pulses of drug,’ said Novakovic. ‘Once those cells are removed and pH levels go up, the delivery will stop.’

She added that she will also be reviewing the possibility of using oscillatory chemical reactions to fuel and propel nano-devices.

The biggest challenge, according to Novakovic, will be to gain a better understanding of how the reactions work. Only then, she added, will they be able to produce predictable results.

‘We need to develop predictive physical chemical models of this system so we can understand how this system achieves oscillations,’ said Novakovic.

She expects to have developed these models by 2014 when the project is expected to end.