New research from the Massachusetts Institute of Technology has found that combining high- and low-frequency ultrasound waves can make skin more permeable to drugs. The finding increases the possibilities for delivering drugs without needles, according to an MIT announcement.
Ultrasound has been shown to increase permeability of skin by lightly removing the top layer, according to the announcement. It creates tiny bubbles in fluid, which pop when they reach a certain size. High-speed "microjets" of fluid--which could include the drug--then rush to fill the space.
Previous research has focused on low-frequency ultrasound, though. High-frequency waves don't contain enough energy to make the bubbles pop, and tend to make abrasions in scattered spots rather than in a single area.
The new research, published recently in The Journal of Controlled Release, finds that high- and low-frequency ultrasound waves can work together--the high-frequency waves produce more bubbles and also corral them to create a more uniform treatment area in which the low-frequency waves can pop them.
"This could be used for topical drugs such as steroids--cortisol, for example--systemic drugs and proteins such as insulin, as well as antigens for vaccination, among many other things," Carl Schoellhammer, an MIT graduate student in chemical engineering and one of the lead authors, said in the announcement.
Using the new method to deliver glucose and insulin on pig skin, the researchers found glucose was absorbed 10 times better than using low-frequency waves alone, and insulin was absorbed four times better. The improved permeability lasts up to 24 hours, offering the potential to administer insulin or other drugs over a significant period.
The researchers are working on a prototype handheld device that might enhance the effectiveness of drugs delivered though skin patches.
The U.S. Food and Drug Administration previously approved single-frequency ultrasound transdermal systems based on the research of two MIT professors who served as senior authors on this work, Daniel Blankschtein and Robert Langer.
Meanwhile, research from Seoul National University in South Korea published at Optics Letters proposed using back-to-back chambers of fluid--one of water, one of the drug--attached to laser pulses to create the bubbles and inject the medication, Popular Mechanics reports.
Diabetics especially are looking to eliminate their daily struggles with needles, with new technologies that include nanosensors that can take readings from fluids such as saliva or tears. German researchers have gone one step further, even, creating nanosensors whose results can be radioed to a mobile device.
And given the health risks that needles themselves pose, effective means to eliminate them can't come too soon.