Painless Drug Delivery Replaces Needles

The system was described in the April 18, 2004, issue of BMC Medicine, the online journal of Biomed Central.

The technique, called microscission, uses a stream of gas to bombard small areas of the skin with tiny crystals of inert aluminum oxide. These particles remove the rough surface layer of the skin and create microconduits in the underlying layers. The crystals and loosened skin are removed by the gas flow. The entire process takes less than 20 seconds. Volunteers reported feeling a gentle stream of air against the skin.

The microconduits formed are invisible to the eye. Their width is defined by the size of the holes punched in a mask made from polyimide film, which is placed over the skin. The researchers used the system to administer a local anesthetic to volunteers. After employing microscission to create four microconduits within a small area, they applied a pad soaked with lidocaine to the region. Within two minutes, the patch of skin was anesthetized and the volunteers experienced a loss of feeling at the site, showing the drug had been successfully delivered.

"The onset of anesthesia takes longer in microconduits deep enough to yield blood than in shallower, nonblood-producing microconduits. Possibly the blood outflow impedes inflow of the externally applied lidocaine, or the clotting blood partially obstructs the microconduit,” noted lead researcher Dr. James Weaver, from the Harvard-MIT Division of Health Sciences and Technology (Boston, MA, USA; www.hst.mit.edu).

However, deeper microconduits that yield spots of blood would be useful to patients with diabetes, who have to regularly check the glucose level of their blood. Currently, they must suffer the pain of pricking their finger with a needle so that a small amount of blood can be used to test for glucose.





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Harvard-MIT Div. of Health Sciences and Tech.
Biomed Central