The article "Ultrasound-Mediated Transdermal Protein Delivery" was
published in SCIENCE, vol. 269, August 11, 1995, pp. 850-853.  There
was also an article summarizing the procedure (obviously much
simplified from the SCIENCE publication) in the New York Times Science
section on Tues., Aug. 15, 1995.  Here are exerpts:

        In a step that may one day free diabetics from painful needles,
researchers at M.I.T. have shown that pulses of ultrasound can inject
drugs like insulin through the skin.
        The skin…is highly impermeable, so only a few small molecule
drugs…can now be administered through the skin with skin patches.
        Dr.’s Langer and  Blankschtein and doctoral student Mitragotri, of the
school’s chemical engineering department, found that pulses of
low-frequency ultrasound significantly increased the skin’s
permeability, allowing insulin…to be delivered from a skin patch.
        "You always have dissolved gases in any tissue," (Dr. Langer) "and
when you apply the ultrasound you could view it as removing the cork
from a champagne bottle: these dissolved gases start to move."
        This phenomenon ("cavitation") causes pathways to develop in the
outermost skin layer…these pathways allow the drugs to pass into the
body.  When the ultra-sound is removed, the lipids quickly reorder
themselves and restore the skin’s impermeability.  
        Dr. Paul Coates, a diabetes program director with the NIDDK, said the
work showed the promise of efforts now under way to develop "A
closed-loop system where you can have glucose-sensing associated with
an insulin delivery system.  …this is a potentially very valuable
method for insulin delivery in diabetes…"
        The tests [were] conducted on human cadavers and live laboratory
mice…Transdermal drug delivery could have several advantages…For
example, patches could reduce needle-transmitted infections.  The
method might more effectively deliver therapeutic proteins that might
be broken down by the digestive system if taken orally….
        Many questions remain to be answered before ultrasound-aided drug
therapies are made available for human use…
        In vivo studies on the long-term effects of ultrasound on the skin’s
barrier properties…as well as tests to determine the optimum pulse
length, frequency and intensity of ultrasound, have yet to be done.
        Dr. Langer said he believed that clinical trials of ultrasound drug
delivery systems could begin within a year.  But he said wearable
devices that would moniter blood chemistry and deliver drugs when
needed were probably many years away.