# Sustained acoustic medicine increases local circulation with a diclofenac delivery patch: a randomized placebo controlled study

## TL;DR

A wearable ultrasound device called SAM boosts local blood flow and temperature, and combining it with a diclofenac patch doesn't reduce its effectiveness.

## Contribution

This study demonstrates that SAM's diathermic effects are sustained and not hindered by diclofenac gel, while enhancing drug delivery through sonophoresis.

## Key findings

- SAM increased blood flow by 19.2 PU and temperature by 2.4°C compared to placebo.
- Diclofenac gel did not affect SAM's biological effects on circulation or temperature.
- SAM's effects on blood flow and temperature were sustained for 60 minutes.

## Abstract

Sustained Acoustic Medicine (SAM) is a non-invasive long-term wearable device that delivers localized long duration high-frequency continuous ultrasound. SAM's biomechanical and diathermic stimuli enhance local circulation and oxygenation, accelerate tissue healing, and alleviate pain. The sonophoresis effects of SAM further improve transdermal drug delivery. Diclofenac is a topical Nonsteroidal anti-inflammatory drug for treating localized musculoskeletal (MSK) pain. Its efficacy is significantly dependent on skin porosity. This study aims to determine the diathermic effects of SAM and diclofenac on localized blood circulation.

Sixty-four healthy participants were randomly assigned to four groups (Active SAM group: n = 32, Placebo SAM group: n = 32): (A) Coupling gel + placebo SAM), (B) Coupling gel + active SAM, (C) 2.5% Diclofenac gel + placebo SAM, and (D) 2.5% Diclofenac gel + active SAM. Both forearms were treated with a placebo and active SAM devices for 1 h. The blood flux (perfusion units, PU) and temperature (degrees centigrade) change were recorded at 10 min intervals for 60 min using high-laser-power Doppler flowmetry. Blood circulation and temperature were recorded and reported (Clinical trial Identifier: NCT06510062).

SAM increased blood flow significantly over 60 min by 19.2 PU (p < 0.0001) with coupling patch and 18.6 PU with 2.5% diclofenac patch (p < 0.0001) vs. placebo. Surface level tissue temperature increased by Δ2.4°C (p < 0.0001) with gel coupling patch and Δ2.2°C (p < 0.0001) with 2.5% diclofenac patch vs. placebo ultrasound treatment (p < 0.0001). There was no significant difference between standard coupling ultrasound gel and 2.5% diclofenac gel in blood flow and temperature. SAM provided a significant temperature increase at 20 min and a circulation increase at 10 min, which remained for the duration of the 60 min. All participants completed the study with no adverse events.

SAM treatment significantly increases local blood circulation after 10 min, increases temperature after 20 min, and sustains the effects of SAM's stimulation. The 2.5% diclofenac gel does not affect SAM's biological effects to increase local circulation. The study concludes that the application of diclofenac does not affect the diathermic properties of SAM exposure while enhancing the efficacy of diclofenac delivery through sonophoresis.

identifier NCT06510062.