| abstract |
Methods for enhanced transdermal transport wherein the application of ultrasound is required only once for repeated or sustained transdermal extraction or delivery, over a period of time, rather than prior to each extraction or delivery. The method is applicable to analyte extraction, as well as for drug delivery. The method involves the initial application of an amount of low frequency ultrasound effective to permeabilize the skin or membrane followed by analyte extraction or drug delivery over a period of time. The initial application of ultrasound is effective to permeabilize the skin or membrane for at least about 30 minutes, preferably at least one to two hours, and more preferably up to four to ten hours. The ultrasound is preferably low frequency ultrasound, less than 2.5 MHz, more preferably less than 1 MHz. The transdermal transport can be enhanced by the application of a secondary driving force such as suction, osmotic pressure gradient, concentration gradient, iontophoresis, electroporation, magnetic field, additional ultrasound, or mechanical pressure. |