Better than a spoonful of sugar
Despite advances in the development of drugs, the task of getting
them into the human body remains a major challenge to modern medicine.
Taking drugs orally – the most commonly used and accepted method of administration – does not work well for some drugs. Other forms of delivery present their own problems: nasal sprays and skin patches are often ineffective; people wince at the thought of injections; and there are forms of insertion that many people refuse to even speak of.
In response to this problem, researchers from UniSA’s Sansom Institute have developed a highly practical and effective way to self-administer medication. And it is as simple as a small adhesive patch that sticks to the inside of the mouth.
The patch, which looks like a circular bandaid, releases the drug into the body through the mouth’s mucosal tissue. Medicines absorbed through the buccal membrane have direct access to the bloodstream, making this a highly effective administration route.
UniSA researcher and PhD candidate Steven Edgecombe says that while one benefit of the patches is their non-invasive practicality, they have many more novel advantages.
“Many drugs taken orally are degraded before they reach the bloodstream, either in the stomach’s acidic environment or during their first passage through the liver. This means that only a small percentage of the ingested drug may reach the bloodstream intact,” Edgecombe said.
To compensate, some drugs have to be administered at doses much higher than would need to be injected so that the desired amount reaches the bloodstream. But this approach, Edgecombe said, can result in a more varied response in patient reactions.
“Everyone’s body is different, and they don’t absorb or metabolise drugs at the same rate. For drugs with a low oral bioavailability (the amount of drug reaching the bloodstream intact following oral administration), even a small difference between patients can result in a large difference in the actual dose received.
“For example, a drug bioavailability range of 0.8-1.2 per cent represents a difference in dose of 50 per cent between the lowest and highest values. For drugs with high bioavailabilities, small differences in bioavailability result in negligible differences between individuals in the amount reaching the bloodstream,” Edgecombe said.
“Compensating for low bioavailability can be expensive - as patients may be paying for a lot more of the drug than is being effectively used.”
By avoiding the stomach, the patches are expected to have a much higher bioavailability than oral administration and therefore are expected to provide a more consistent response.
Made of polymers, the patch, known as a “platform device”, is small and flexible, and stays firmly gripped to the buccal membrane.
“In the past muco-adhesive patches have been experimented with but with a certain drug incorporated. This patch is an entity in itself, so conceptually, we can put anything onto it,” Edgecombe said.
As a multi-purpose product, the patches will benefit many varied end-users.
“It will be handy in any situation where a small amount of a potent drug is needed but intravenous administration isn’t practical. For instance, it will be good for migraine sufferers, because the stomach often shuts down, meaning that tablets can’t be absorbed,” Edgecombe said.
The patches will also be especially valuable for treating nausea.
“The most common way of treating nausea is to swallow an anti-nausea tablet, but if people aren’t holding any food down, then it’s unlikely much will be absorbed into the bloodstream.”
The patches are also good for patients who have fallen unconscious, as there is no need to swallow. Another possible application could be for diabetes treatment.
“Currently, compliance with insulin therapy is a big challenge due to the pain and inconvenience associated with injecting, so this product could revolutionise diabetes treatment,” Edgecombe said.
The Director of the innovative research area, Professor Allan Evans, added:
“Buccal absorption has the potential to overcome a multitude of administration problems. It has remained an untapped resource until now, probably because issues were encountered in production. But we believe we have designed a delivery system that is eminently manufacturable, and so there should be a real future for this product in the market.”
The newly established Sansom Institute brings together internationally recognised research concentrations in quality use of medicines and pharmacy practice, pharmaceutical science and biomedical science. Offering a unique breadth of medicines related research, the Sansom provides a dynamic multidisciplinary environment, enabling world class research and research training in a collaborative and cooperative spirit. Housing state of the art laboratory and pharmacy research facilities, the Sansom Institute offers an outstanding research facility for postgraduate students and early career researchers.
The Institute’s three major research sectors are complemented by a commercial studies unit that provides services to the national and international biotechnology and pharmaceutical industries.