Sonophoresis therapeutic

Various ultrasound intensities in the range of 0.1-2W/cm have been used for sonophoresis. In most cases, use of higher ultrasound intensities is limited by thermal effects. Several investigations have been performed to assess the dependence of sonophoretic enhancement on ultrasound intensity. Miyazaki, Mizuoka, and Takada. foimd a relationship between the plasma concentrations of indomethacin transported across the hairless rat skin by sonophoresis (therapeutic conditions) and the ultrasoimd intensity used for this purpose. Specifically, the plasma indomethacin concentration at the end of three hours after sonophoresis (0.25 W/cm ) was about 3-fold higher than controls at the same time. However, increasing intensity by 3-fold (to 0.75 W/cm ) further increased sonophoretic enhancement only by 33%. Mortimer, Trollope, and Roy found that application of ultrasoimd at IW/cm increased transdermal oxygen transport by 40%i while that at 1.5 W/cm and 2 W/cm induced an enhancement by 50%i and 55 /o, respectively. 

Power ultrasound, Sonophoresis, Therapeutic ultrasound. Nondestructive ultrasound. 

Sonophoresis has employed three distinct categories of US high-frequency or diagnostic US (2-10 MHz), mid-frequency or therapeutic US (0.7-3 MHz), and low-frequency US (5-100 kHz). It appears, from a general overview of the literature, that the efficiency of US-mediated drug delivery depends on several factors, including US frequency, intensity (i.e., power per unit area), continuous versus pulsed mode, duty cycle, duration, coupling medium, and so on. The fact that very few studies have used common values for some or any of these parameters almost certainly accounts for the different and sometimes contradictory results in the public domain. 

Ultrasound at various frequencies in the range of 20 kHz to 16 MHz has been used for sonophoresis. These studies of sonophoresis can be classified into three categories based on the ultrasound frequency used, i.e., therapeutic, high-frequency, and low-frequency ultrasound. 

Numerous attempts of sonophoresis have been performed over the last 40 years. As described earlier, these attempts can be classified into three categories therapeutic frequency, high-frequency and low-frequency ultrasound. 

Power ultrasound (20-100 kHz) Sonophoresis (20 kHz, low power) Therapeutic ultrasoimd (1 MHz, high power) Nondestructive ultrasound (> 2 MHz, low power)... 

---