Ultrasound-Enhanced Ciclopirox Delivery for Treatment of Onychomycosis.

The study aim was to determine ultrasound's efficacy in increasing the permeability of the nail in order to improve treatment outcomes in onychomycosis. Three sets of ultrasound experiments were performed - the luminosity experiment and two sets of diffusion cell experiments. The luminosity experiments assessed dye levels inside the nail after ultrasound application as compared to sham treatments, and the diffusion cell experiments compared changes in nail permeability due to the application of ultrasound. All in vitro experiments used planar ultrasound transducers, frequencies of 400 kHz, 600 kHz, 800 kHz, and 1 MHz, an intensity of 1 W/$cm^{2}$ and a duration of 5 min in a continuous mode. The safety of applying ultrasound to the toe was assessed by performing modeling studies. It was found that application of ultrasound at higher frequencies (800 kHz and 1 MHz) resulted in more (and statistically significant) permeation of the nail, as compared to the control trials.