Diathermic Evaluation of Sustained Acoustic Medicine with Cannabidiol Coupling Gel

Musculoskeletal (MSK) pain is a prevalent clinical condition that significantly impairs quality of life, and current treatment options are not effective on all patients or have severe, long-term side effects. Sustained Acoustic Medicine (SAM) delivers therapeutic ultrasound, providing diathermic and mechanical stimulation to local tissue and facilitating healing. Additionally, therapeutic ultrasound has been shown to enhance transdermal drug delivery via sonophoresis. Cannabidiol (CBD) is a small molecule that has been shown to have anti-inflammatory effects drug delivery. However, CBD has never been studied in conjunction with therapeutic ultrasound, and its potential effects on ultrasound efficacy are unknown. Therefore, this study compares standard high viscosity ultrasound (US) gel and commercially available CBD gel both in terms of acoustic properties and in an ex vivo bovine muscle model with SAM treatment. The acoustic properties of CBD & US gels were measured using a hydrophone, an oscilloscope and a function generator. The function generator propagated a pulsed wave through each gel, and the time between the original and reflected waves was used to determine the acoustic coefficients. Then, a SAM transducer was positioned and placed into the coupling bandage and gel depot on the bovine muscle with 3 mL of US gel or CBD gel. Tissue was stimulated by SAM for 240 min with a 60-min cooldown, and internal muscle temperatures at 1 cm, 2 cm, and 5 cm were continuously monitored. US gel and CBD had no significant differences in their acoustic properties. There were no significant differences in the change in temperature for SAM treatment with CBD gel compared to SAM treatment with US gel at 1 cm (Δ12.06 ± 1.04 °C vs. Δ12.52 ± 1.84 °C, p > 0.05), 2 cm (Δ8.13 ± 1.01 °C vs. Δ8.97 ± 1.04 °C, p > 0.05), and 5 cm (Δ4.83 ± 0.91 °C vs. Δ3.83 ± 0.66 °C, p > 0.05). CBD gel does not compromise SAM’s ultrasonic delivery and diathermic efficacy, making this combination a novel option for musculoskeletal rehabilitation. Future studies could explore changes in transdermal CBD delivery with SAM treatment for deep tissue delivery.