Single flexible ultrasound transducer for enhancement of permeability of silicone membrane

A flexible ultrasound transducer has been proposed for sonophoresis application. In order to explore the feasibility of using this newly developed transducer for drug delivery application, a series of experiments was conducted with silicone membranes and over-saturated lidocaine solution. The device was mounted in a vertical Franz diffusion cell and it was operated at a frequency of 17.47 kHz. The permeability of the silicone membrane was enhanced by 2.81 ± 0.73-fold with ultrasonic irradiation. The enhanced permeability increased with the increase of irradiation time and acoustic intensity. In order to find out whether the surface morphology was changed by cavitation. The surface morphology of the sonicated silicone membranes was checked using the scanning electron microscope (SEM). The observation did not reveal any micro holes or cracks. However, diffusive experiments revealed the permeability of the sonicated silicone membrane is about 3.9-34.1% higher than that of non-irradiated membrane. It was shown that the permeability of the silicone membrane recovered partially. It is also confirmed that the structure of the sonicated silicone membrane was damaged permanently. The modifications of the silicone membranes may be in the molecular scale, which could not be identified by the limited resolution SEM used in this study.