Ratio of area under the plasma concentration time curve from 48-72 hrs (AUC48-72 hrs) of Diclofenac gel in tube and AUC48-72 hrs of oral Diclofenac during the final 24 hours of dosing at steady state will assess systemic exposure to Diclofenac from gel as compared to that from oral Diclofenac

Ratio of maximum plasma concentration (Cmax) of Diclofenac gel in tube and Cmax of oral Diclofenac during the final 24 hours of dosing at steady state will assess systemic exposure to Diclofenac from gel as compared to that from oral Diclofenac

Ratio of AUC48-72 hrs of Diclofenac gel in roll-on device and AUC48-72 hrs of oral Diclofenac during the final 24 hours of dosing at steady state will assess systemic exposure to Diclofenac from roll-on device as compared to that from oral Diclofenac

Ratio of Cmax of Diclofenac gel in roll-on device and Cmax of oral Diclofenac during the final 24 hours of dosing at steady state will assess systemic exposure to Diclofenac from roll-on device as compared to that from oral Diclofenac

During the Induction Phase, the test article and three controls will be applied to adjacent treatment sites on the infrascapular area of the back for nine 48-hour patch applications. Evaluation of dermal reactions at the application sites will be conducted clinically using a visual scale that rates the degree of erythema, edema, and other signs of cutaneous irritation at nine intervals spaced approximately 48-72 hours apart. Following the Induction Phase participants will return to the clinic to begin the Challenge Phase after 12 to 14- day rest phase. The Challenge Phase will consist of one 48-hour patch application to a naive site on the opposite side of the back. Evaluations of dermal reactions at the application sites will be conducted clinically during the Challenge Phase using the same visual scale at 30 minutes, 24 hours, 48 hours, and 72 hours after removal of the challenge patch.