Scalable high-power ultrasonic technology for the production of translucent nanoemulsions

Oil-in-water nanoemulsions are widely used in cosmetics, pharmaceutical, food, agricultural and other industries as delivery systems for active lipophilic compounds and drugs. Translucent nanoemulsions are especially attractive because their extremely small droplet sizes lead to long-term stability, improve absorption by the skin and enable the delivery of exceptionally high concentrations of active substances. High-power ultrasound has previously been successfully used to produce translucent nanoemulsions on laboratory scale. However, due to limitations of conventional ultrasonic liquid processing technology, scaling up has not been possible, restricting industrial implementation of this process. In this study, ultrasonic production of translucent oil-in-water nanoemulsions was optimized on a laboratory scale and then directly scaled up. The ultrasonic amplitude played a significant role in this process, and was determined to be optimal near 90 μm peak-to-peak. Barbell Horn Ultrasonic Technology was employed to scale up the process by a factor of 10 without reducing the ultrasonic amplitude or compromising the product quality. The scale-up procedure is described in detail. Further scale-up by a factor of five is theoretically shown to be possible, potentially making high-power ultrasound an important industrial method for producing nanoemulsions.