The investigators hypothesize that a technique called microdialysis can be used to measure
the amount of the drug diclofenac which penetrates (enters) the fatty tissue under the skin.
Microdialysis uses a small device called a 'probe' to determine the amount of drug which
enters a body tissue. The small device is placed directly in the fatty tissue and samples are
taken at specific times. The investigators will determine whether site of application affects
the availability of the drug.