Researchers from MIT have discovered a method to make delivering drugs through skin easier, in doing this, noninvasive drug delivery and vaccines without needles may become possibilities.
Carl Schoellhammer, an MIT graduate student in chemical engineering and one of the lead authors of a new paper concerning the new method, commented:
“This could be used for topical drugs such as steroids – cortisol, for example- systematic drugs and proteins such as insulin, aswell as antigens for vaccination, among many other things.”
Ultrasounds, or waves of sound with frequencies higher than what the human ears can hear, work by making skin more permeable by means of painlessly removing the top layer of skin. The trial, which is published in the Journal of Controlled Release, revealed that when one low frequency ray of ultrasound waves and one with high frequency were applied, it made the skin more permeable than just using one beam of ultrasound waves.
When traveling through a fluid, ultrasound waves make small bubbles that move around in a state of confusion. The bubbles become unsteady when they reach a certain size causing them to collapse inward. The fluid around them fills the empty spaces, which results in fast-moving “microjets” of liquid which makes tiny cuts on the skin’s surface. For this study, the fluid may either be water or some type of fluid which consists of the drugs being delivered.
Usually, scientists who are trying to make transdermal drug delivery more efficient stay away from using high-frequency ultrasounds because they don’t contain the amount of energy needed to pop the bubbles, therefore, they tend to use the low-frequency ultrasounds. However, these systems often result in many scrapes or cuts on the skin in random places.
Samir Mitragotri, a chemical engineering professor at the University of California at Santa Barbara, said: “It’s a very innovative way to improve the technology, increasing the amount of drug that can be delivered through the skin and expanding the types of drugs that cold be delivered this way.”
To determine if their new method worked, the experts experimented on pig skin. They discovered that it enhanced the permeability of the skin much more than a single wave would have. To test it, they transported the ultrasound waves to their destinations, then worked in the inulin (a carbohydrate) or glucose.
They found that inulin was absorbed 4 times better than before they utilized the two frequency methods, and glucose 10 times better.
“We think we can increase the enhancement of delivery even more by tweaking a few other things,” said Schoellhammer.
According to the report, any type of drug that is normally in capsule form could be delivered by using this kind of system, which would increase the allowed dosage being given.
Acne and psoriasis drugs could be delivered more efficiently. Individuals who wear nicotine patches could benefit greatly from such a system, and they would not have to wear the uncomfortable patch any longer. Diabetics would be able to receive their medication easier, therefore controlling their glucose levels without painful pinches.
The researchers say that after an ultrasound therapy, the enhanced permeability may stay for up to 24 hours, which would make way for drugs such as insulin to be delivered for a long period of time.
Administering vaccines could be made easier, for the patient and doctor, with this type of system. And developing countries may benefit from the ultrasound therapy because the training would not be as intense for teaching new doctors to give injections for vaccines ect.
The U.S. Food and Drug Administration (FDA) has approved single-frequency ultrasound transdermal systems in the past, and the researchers are optimistic that this system will be approved as well.
Written by Christine Kearney