Ultrasonically mediated solute permeation through polymer barriers.

The effects of ultrasound on the permeation of benzoic acid through polydimethylsiloxane, and hydrocortisone through cellulose was investigated. Ultrasonic irradiation resulted in a 23% increase in the permeability coefficient of hydrocortisone in a cellulose film. A 14% increase in permeability coefficient was observed for benzoic acid in a polydimethylsiloxane film. The effects of ultrasound on stagnant aqueous diffusion layers, membrane-solution interfacial temperature, membrane integrity, and diffusant stability were investigated. These factors were not responsible for the observed increases in permeability.