Phonophoresis in Physiotherapy: Mechanisms, Applications, and Emerging Trends for Enhanced Drug Delivery and Therapeutic Efficacy

Abstract

Phonophoresis, a widely utilized treatment in physiotherapy, combines topically applied gel or cream-based medications with ultrasonic therapy to enhance percutaneous absorption of pharmacological agents. The procedure employs ultrasound frequencies of 0.7 to 1.1 MHz with intensities ranging from 0.0 to 3.0 Watts per cm². Indications for phonophoresis span various inflammatory, deformative, dermatological, and rheumatic/neurological conditions. Recent studies suggest its clinical efficacy in pain relief and improved function, especially in conditions like lateral epicondylitis and osteoarthritis. The mechanism of action involves both thermal and non-thermal effects, with cavitation playing a key role in enhancing transdermal transport. Phonophoresis offers a non-invasive alternative for drug delivery, bypassing hepatic metabolism and minimizing systemic side effects. Various medicinal gels, particularly diclofenac, are used for transdermal drug delivery through phonophoresis. Low frequency phonophoresis has gained attention for enhancing transdermal transport, especially for macromolecules. Its applications extend beyond physiotherapy to include ocular drug delivery, nail therapy, gene therapy, and sports sciences. Clinical studies demonstrate the effectiveness of phonophoresis in conditions like anterior knee pain, tuberculous lymphadenitis, acute low back pain, and latent myofascial trigger points. Dosage considerations emphasize optimizing thermal effects without causing tissue damage. Studies highlight the potential of phonophoresis in relieving pain and improving function, particularly in knee osteoarthritis. Additionally, phonophoresis with Phyllanthus amarus nanoparticle gel shows promise in reducing pain and enhancing functional capacity in symptomatic knee osteoarthritis. In summary, phonophoresis stands as a valuable modality in physiotherapy, showcasing diverse applications and demonstrating clinical efficacy in various musculoskeletal and inflammatory conditions. Further research is warranted to explore its full potential and optimize treatment protocols.