The market for drug-delivery systems has received a major boost following a breakthrough by researchers that could see syringes and needles become a thing of the past in vaccine administration.
A team of researchers at King's College London has tested the impact of metal-free microneedles for the delivery of a freeze-dried vaccine attached to glucose spikes.
Infection with HIV, malaria and tuberculosis represents a global public health challenge
The breakthrough has the ability to deliver a dried live vaccine to the skin without the need for a traditional needle and would still be powerful enough to enable specialised immune cells in the skin to kick-start the immunising properties of the vaccine.
It will help to address the problem of fragile vaccines that have to be kept at an uninterrupted refrigerated condition spoiling or becoming ineffective, particularly when used in resource-limited settings, such as in Third World countries.
The method would also require less training to administer and would help to reduce needlestick injuries, which are a significant hazard among healthcare workers administering vaccines to infected patients. In addition, it could also be used for patients suffering from a fear of needles, known as trypanophobia.
Early tests of an experimental HIV vaccine on mice have found the method to be as effective as the conventional liquid version injected more deeply by needle. However, while the injectable liquid equivalent would have to be preserved at a constant temperature of -80 degrees Celcius, the dried microneedle vaccine can be stored and transported at room temperature.
The latest development in an ongoing search for a ‘needleless’ syringe, the research heralds a new approach to the treatment of infections such as HIV, tuberculosis and malaria.
Lead researcher, Linda Klavinskis, said: “This work opens up the exciting possibility of being able to deliver live vaccines in a global context without the need for refrigeration.”
This work opens up the exciting possibility of being able to deliver live vaccines in a global context without the need for refrigeration
The research team used a silicone mould developed by US-based biotech company, TheraJect, to create a tiny microneedle array – a small disc with several small ‘microneedles’ made of sugar, which dissolve when inserted into the skin. Once applied, the pressure is enough to open the surface layer and allow the vaccine to penetrate the skin.
The company has already licensed the technology for anti-wrinkle treatments and is developing applications for migraine and pain remedies. If proven to work for vaccines, it intends to offer the technology to Africa at no profit.
It is a step forward for current drug delivery systems that use patches and nasal sprays to administer medicines such as nicotine replacement therapy. These methods have limits as far as vaccines are concerned and are usually restricted to non-live vaccine platforms.
The study says: “Infection with HIV, malaria and tuberculosis represents a global public health challenge.
“Developments in microfabrication technology have enabled ultrasharp, micrometer-scale projections to penetrate the skin, containing lyophilised vaccine coated on metallic structures or encapsulated with dissolvable polymers. Designs under evaluation, however, have largely been restricted to non-live vaccine platforms.
“We have made an important technical advance to enable the possibility of live vector stability and delivery in a global context
“The capacity of this new generation of live recombinant vaccines to prime cells as dried microneedle arrays (MAs) via the skin has been largely unexplored.”
The research concludes: “[We have made] an important technical advance to enable the possibility of live vector stability and delivery in a global context. This data may have important implications for recombinant viral vaccine vectors advancing to the clinic and shed light on the early events after MA delivery.”
The study was funded by the Bill & Melinda Gates Foundation and was published in Proceedings of the National Academy of Sciences. If developed, there are indications it could also be used in the ongoing management of autoimmune and inflammatory conditions such as diabetes.
Click here to read the research.
