The key to turning the chemical compound polyvinyl-alcohol (PVA) into a viable material to aid the delivery of drugs is its compatibility with the human body. Previous studies have demonstrated its suitability as a material for drug delivery due to its biocompatibility and hydrophilic nature.
Biological barriers
If successful, the recycling of what would normally be waste material could create the prospect of new drug delivery vehicle housed by a PVA-derived polymer that could cross the biological barriers in the body and reach their target.
The researchers from the University of York describe a method in which the PVA is first heated then cooled to a certain temperature. By dehydrating it with ethanol the researchers produce a high surface area mesoporous material that could well have potential for biomedicinal uses.
“Now we have gone a step further by enhancing its anti-microbial properties through the addition of silver nanoparticles,” said Dr Andrew Hunt, of the York Green Chemistry Centre of Excellence.
“The result being that it can destroy bacterial infections such as E.coli. Potentially, it could be used in hospital cleaning products to help to reduce infections.”
Since the major source of PVA is liquid crystal display (LCD) technology, 2.5bn LCD televisions currently discarded by consumers worldwide can be reused in a medicinal role, potentially with life saving benefits.
The researchers also commented that the next steps would be to test the PVA-based substance against commercial compounds to determine relative effectiveness.
The way forward would be to secure approval from regulatory agencies regarding the suitability of silver nanoparticles for human health applications, according to the team.
On its own PVA exhibits poor water resistance and insufficient mechanical strength, which has limited its application. Normally, pharmaceutical manufacturers combine PVA with excipients such as ethylcellulose, hydroxymethyl-cellulose, xanthan gum, chitosan, polyethylene oxide, and wax to improve its properties.
More recently, PVA has been the intense focus in ocular drug delivery where polymeric inserts and discs have been developed to target the permeability of the eye to deliver therapies that treat conditions such as Age-related Macular Degeneration (AMD).
Systemic side effects
These inserts allow for accurate dosing, reduced systemic absorption and better patient compliance resulting from reduced frequency of administration and lower incidence of systemic side effects.
Considering the dearth of suitable drug delivery options currently available companies in this sector are keen to get their products into the market which is worth $6bn, according to biotech company QLT.
Biotechnology companies that are currently developing ocular drug delivery technologies include pSivida and Iris Pharma, a Contract Research Organisation (CRO) for drug development in ophthalmology.
The research will be presented by Dr Andrew Hunt at the 14th Annual Green Chemistry and Engineering Conference in Washington DC, US on 23 June.