The efficacy profile of PENNSAID Gel is based on the known efficacy profile of PENNSAID solution. Support for the BID dosing regimen includes the higher concentration of diclofenac sodium in PENNSAID Gel (2.0%) compared to PENNSAID solution (1.5%). In addition, compared to PENNSAID solution, PENNSAID Gel is designed to have better penetration of diclofenac to allow for a reduction in the number of applications per day from four to two while maintaining effectiveness.