Traditionally yeast has been used for making beer and bread. But researchers at Leeds University have found that it may be crucial in helping diabetic patients to deliver insulin – up the nose.
The preliminary research, reported at the British Pharmaceutical Conference today ( 26 th September ), found that specially treated yeast might help to deliver insulin through the nasal mucosa ( the layer of tissue lining the nose ). A nasal spray formulation would avoid the need for regular insulin injections for patients with diabetes.
Getting insulin into the bloodstream via the nasal mucosa is tricky. The molecule is too large to readily penetrate through the nasal tissue and some sort of penetration enhancer is needed.
Emily Fuller, from the School of Biochemistry and Microbiology at Leeds University , has been investigating the properties of yeast as a penetration enhancer. She explained: “Transport of large molecules, such as insulin, through the nasal mucosa is limited because of the tight structure of the cell layer which forms an impenetrable barrier. Penetration enhancers work by opening this barrier.”
Ms Fuller says: “Our laboratory results show that yeast cells successfully enhanced the penetration of insulin. Yeast is beneficial as a penetration enhancer because it shows reversible effects, is non-toxic and is readily available.”
Yeast has structural similarities to chitosan, an established penetration enhancer, but the mechanism of how yeast opens the tight junctions between nasal cells is not yet clear. Further studies to investigate this are underway.
Another strand of the Leeds research is to investigate the use of yeast as a drug delivery system. The idea here is that it might be possible to encapsulate active drugs inside the yeast cell, to protect the drugs until they get to their site of action as well as acting as a penetration enhancer.
Ms Fuller’s research is part funded by Micap Plc, a company that specialises in microencapsulation and delivery of active agents using yeast cells, and the Biotechnology and Biological Sciences Research Council. (BBSRC)
