Tuesday, September 18, 2012

Ultrasound Enhances Transdermal Drug Delivery

Most medical drugs are administered as an injection or are taken orally as pills or liquids.  Both drug delivery methods have their drawbacks; injection requires at least some technical expertise and the availability of sterile syringes and needles and also involves some pain.   Oral ingestion is not very effective for proteins and other macromolecules that are easily degraded by the digestive system.

The idea that ultrasound could be used to enhance the delivery of drugs directly across the skin (transdermal delivery) has been around for many years.  Progress was slow until about two decades ago, when it was discovered that low-frequency sound waves (20-100 kHz) were more effective than the higher frequencies (700 kHz and above) being used at the time.  If you’re interested, see the review on this subject published in 2010.

A potential breakthrough in the field came this month when the same authors who wrote the 2010 review published new data showing that using both low- and high-frequency ultrasound together caused better drug absorption across the skin than using either frequency alone.   A proposed mechanism for the enhancement is described in the paper, reviewed this week by ScienceDaily.

A lot of work still needs to be done (including safety and effectiveness studies and finally FDA approval) before ultrasound-enhanced drug delivery becomes commonplace.  But its likely that in your lifetime, you’ll be prescribed a therapeutic drug in a cream or ointment form and given a small hand-held ultrasound device to enhance its absorption through the skin.

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