Iontophoresis and phonophoresis for targeted transdermal drug delivery systems have been widely used and are well-accepted physical therapy modalities. The mechanisms and techniques used to deliver drugs to the soft tissues of the musculoskeletal system must be well understood to ensure efficacious and safe treatment. Not all drug agents can be used in conjunction with these technologies – the use of certain drug agents would not result in adequate permeation across the stratum corneum in quantities sufficient to bring about a positive therapeutic outcome. Furthermore, the differential diagnosis and causative factors at a physiological level must be taken into account to ensure correct drug selection.

In recent years, the diagnostic use of ultrasound has proven instrumental in understanding the effects of drug agents on soft tissue. Ultrasound-guided treatment has also improved the efficacy of invasive therapeutic interventions. The correct technology settings and conductive properties of the carrier and transport systems must be properly matched to the physicochemical properties of the drug agent such that appropriate drug penetration, partitioning, diffusion, and permeation is achieved. The use of drug-free microneedle systems, figuratively and literally, paves the way for the enhancement of targeted transdermal drug delivery.