The team from Queen’s University Belfast, the University of Strathclyde, and the University of Glasgow found that the foam, found in frogs nests, has the potential to offer benefits to topical, vaginal and rectal drug delivery. It provides a controlled -release delivery, which minimises risk of infection and antimicrobial resistance, while the organic form also reduces risk of allergy.  

Industrial foams have long been used for the delivery of cosmetics and medications, however there is high variability in the foamability and long-terms stability of synthetic foams.  

The researchers collected foam from wild túngara frogs, which protects this species from the elements in its native Trinidad, including extreme temperatures as well as harmful bacteria. 

As the foam offered protection in these extreme conditions, the researchers hypothesised that it could offer a more durable system for drug delivery. They carried out laboratory tests to assess its structure and composition. The researchers also made nanoparticles to deliver drugs through the foam and found that the foam released the compounds slowly while the structure held together.  

The research has been published in the Royal Society Open Science. 

Dr Dimitrios Lamprou, from the School of Pharmacy at Queen’s University Belfast, explains: “In testing the foam in our labs, we analysed the properties of the foam and were impressed that not only was it strong and durable, but when we administered drugs, they were released over a long period of time. This controlled release and stable compounds has huge implications for drug delivery.  

“One practical example could be with burn treatment whereby the foam would enable the drugs to be delivered under the bandage over a longer period, without needed to remove the bandages frequently, which would reduce the chance of infection. Organic structures are also less irritable and less likely to cause allergies to human skin. Further testing is needed, but we are excited about the prospect of this novel drug delivery which could be used for proteins or siRNA.” 

The team have successfully produced the foam’s proteins in a laboratory using bacteria, acknowledging that the frogs won’t be able to produce enough foam to meet manufacturing demands. The next stage of the research will focus on the ability to scale up the reproduction of the exact foam properties in a laboratory setting.  

Dr Paul Hoskisson at the University of Strathclyde and researcher on the study, added: “This is the first time an amphibian foam has been used for drug delivery. It should give us a nice, safe delivery vehicle that can be administered to patients without any fear of making them sick, unlike many of the other synthetic delivery vehicles. We are now looking at reproducing the exact foam as well as more focus on analysing more drugs to see which drugs lend themselves better to this type of drug delivery.”