ABSTRACT
Sonophoresis is shown to enhance transdermal drug transport by Fellinger and Schmidt who showed that application of ultrasound increases transport of hydrocortisone across the skin. For sonophoretic delivery, the desired drug is dissolved in a solvent and applied on the skin. A coupling medium is appropriate for sonophoresis if its acoustic impedance is comparable to that of skin. Proper selection of ultrasound parameters is required to ensure safe and efficacious sonophoresis. Ultrasound at various frequencies in the range of 20 kHz to 16 MHz has been used for sonophoresis. Among all the drugs that have been used for sonophoresis, much attention has been focused on anti-inflammatory drugs. In order to understand the mechanisms of sonophoresis, it is important to identify various effects of ultrasound exposure on the human tissue since one or more of these effects may contribute to the mechanism of sonophoresis.
