Context: Transdermal delivery of hydrocortisone by phonophoresis is used for the treatment of musculoskeletal conditions. Research shows hydrocortisone and other white or opaque topical preparations transmit ultrasound energy poorly. Effective transmission of ultrasound is important in phonophoresis. Main Outcome measured: Samples of subcutaneous interstitial fluid were collected during and for 20 minutes following phonophoresis treatment. Cortisol concentrations were analyzed by an enzyme linked immune-assay (ELISA) test. Objective: Determine the subcutaneous cortisol concentration after two different phonophoresis treatments using a 2.5% hydrocortisone preparation. Design: Randomized design in which 22 healthy participants were assigned to receive a phonophoresis treatment where: 1) hydrocortisone cream was rubbed in completely prior to phonophoresis or 2) hydrocortisone powder was compounded with an ultrasound coupling gel. Test Subjects: 22 healthy individuals were recruited: 13 females with a mean age of 21 years and 9 males with a mean age of 21.8 years. Intervention: Phonophoresis consisted of pulsed ultrasound at 1 MHz, 1.0 w/cm2, and a 50% duty cycle. The treatment duration was 10 minutes and was localized over the distal gastrocnemius muscle. Results: We observed no significant difference in subcutaneous cortisol concentration between the two phonophoresis treatments (p=0.05). Also no significant difference was detected between pre and post-treatment cortisol levels within each individual treatment group. Conclusions: Our data indicates that completely rubbing a topical hydrocortisone application into the skin prior to placement of ultrasound gel does not result in increased transdermal delivery of cortisol when compared with the use of a compound of ultrasound gel and hydrocortisone powder applied topically to the skin.



College and Department

Life Sciences; Exercise Sciences



Date Submitted


Document Type





phonophoresis, hydrocortisone, microdialysis