Diclofenac phonophoresis in human volunteers

A quantitative study of sodium diclofenac (Voltaren Emulgel (R), Novartis) phonophoresis was undertaken in humans. Fourteen healthy human volunteers were submitted to ultrasound irradiation on two 225-cm(2) areas on the dorsum (group A), followed by the application of the medication gel, and the plasma diclofenac mass was measured at 1, 2 and 3 h later by high performance liquid chromatography. The same procedure was repeated one month later with the same volunteers but with the ultrasound equipment switched off for the control group (group B). The plasma diclofenac mass was significantly higher in group A than in group B at 1 h (0.0987 mu g/mL as opposed to 0.0389 mu g/mL; p = 0.01) and 2 h (0.0724 mu g/mL as opposed to 0.0529 mu g/mL; p = 0.01), but not at 3 h (0.0864 mu g/mL as opposed to 0.0683 mu g/mL; p = 0.16). The authors conclude that previously applied therapeutic ultrasound irradiation enhances the percutaneous penetration of the topical diclofenac gel, although the mechanism remains unclear. (c) 2005 World Federation for Ultrasound in Medicine & Biology.