London: Scientists at Yonsei University in Seoul, South Korea, have suggested that a skin patch could soon provide efficient pain relief whenever you flex sore muscles.
The system would work by synchronising the release of drugs with movement of the underlying inflamed tissue.
Unyong Jeong`s team at Yonsei University covered a flexible rubber film with a sheet of corrugated microporous polystyrene, with gutters around 3 micrometres wide and 1 micrometre deep, reports New Scientist.
The gutters were then filled with a liquid and sealed with another rubber film. Finally, the first rubber film was peeled away to expose the underside of the liquid-filled polystyrene gutters.
Flexing the patch distorts the polystyrene tunnels enough to reduce their volume, squeezing the solution out through the pores in the plastic. Once the strain is removed, the tunnels spring back into shape, ready for the next use.
Jeong and his team demonstrated the mechanism with a dye solution, but they are now moving on to therapeutic applications.
He envisaged the first practical use will be skin patches for treating muscle pain and rheumatism.
"Current [skin patches] are designed to just continuously release the active agents," he said.
"If we can control the release rate responding to the motion of our muscles, it will make the patches more effective and prolong the time of use," he added.