University of South Florida

Michael VanAuker

Joel A Strom

Elizabeth Hood

A method of targeted drug delivery and imaging using nonionic surfactant vesicles (niosomes) in combination with ultrasound is presented. Niosomes have potential applications in targeted drug delivery and imaging because of their ability to encapsulate therapeutic agents and their enhanced uptake by physiological membranes. The niosomes may be administered to the subject via catheter. Ultrasound may be used to mediate delivery non-invasively by altering the niosome membrane structure. Niosomes composed of polyoxyethylene sorbitan monostearate (Tween 61), cholesterol, and dicetyl phosphate were synthesized via a thin film hydration technique and used for encapsulation studies. Carboxyfluorescein dye (CF) was used as a drug model to demonstrate delivery. The amount of dye in the niosomes, the concentration of the vesicles, and their mean particle size after each 5 minute incremental exposure to ultrasound was monitored. It was found that ultrasound at specific frequencies can reversibly permeabilize the lipid membrane of niosomes to allow the controlled release of a compound without destroying the niosome structure.

Ultrasound enhancement of drug release across non-ionic surfactant membranes

A method of targeted drug delivery and imaging using nonionic surfactant vesicles (niosomes) in combination with ultrasound. Niosomes have potential applications in targeted drug delivery and imaging because of their ability to encapsulate therapeutic agents and their enhanced uptake by physiological membranes. Ultrasound may be used to mediate delivery non-invasively by altering the niosome membrane structure. Niosomes composed of polyoxyethylene sorbitan monostearate (Tween 61), cholesterol, and dicetyl phosphate were synthesized via a thin film hydration technique and used for encapsulation studies. Carboxyfluorescein dye (CF) was used as a drug model to demonstrate delivery. The amount of dye in the niosomes, the concentration of the vesicles, and their mean particle size after each 5 minute incremental exposure to ultrasound was monitored. Dye concentration in niosome samples decreased while the population and size distribution of the niosome remained largely unchanged. Ultrasound is demonstrated to enhance the rate of dye diffusion across the niosome membrane non-destructively.

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Santa Clara, CA, United States of America

Michael VanAuker