Yeast could deliver insulin as a spray
insulin via a nasal spray using yeast, which would open up the way
for a spray to be developed to replace injections.
The discovery is good news for patients that dislike the rigmarole of injections that form the basis of diabetes control and therapy. While non-injectable insulin has been hailed as the future, there are still manufacturing issues that prevent this method of drug delivery from becoming the preferred one.
Researchers from Leeds University have found that the fungus, which is normally used to make beer and bread, opened a person's nasal cells to allow insulin to pass through nose tissue.
Subsequent results showed that yeast cells successfully enhanced the penetration of insulin. Preliminary research found that the yeast, which is non-toxic, opened up the tight junctions between nasal cells.
Getting insulin into the bloodstream through the nose is tricky because the layers of tissue lining the nose, known as the nasal mucosa, can block the molecule.
The researchers thought that the yeast's properties would make it a suitable drug delivery system with the possibility of encapsulating active drugs inside yeast cells to protect them until they get to the site of action.
In the UK, there are around 700,000 people with diabetes whose only treatment option is daily insulin injections with more than 1.7m people in England have diabetes
The team, which presented its findings at the British Pharmaceutical Conference in Manchester, were quick to point out that despite the excitement over this discovery more research was needed.
Current market potential of a new non-injectable insulin product such as Exubera is as high as $1.5 billion (€1.3 billion) a year. However, non-injectable insulin have some inherent disadvantages, in particular increased costs and a loss in accuracy of the insulin dosage due to the external mode of delivery
Another major hurdle that these products need to overcome is the increased cost - expected to be at least double that of injectable insulin.
This may be because non-injectible insulin is less effective than an injection at delivering a precise insulin dose, as only a small percentage the insulin that is inhaled actually reaches the bloodstream, so patients have to inhale a lot of insulin to get the amount their body needs, "wasting" a lot in the process.
