Topical application of ketoprofen improves gait disturbance in rat models of acute inflammation.

Arthritis is a disabling health problem and commonly develops in the late stages of life; the condition is typically accompanied by chronic pain. For the assessment of pain severity and therapeutic effects of analgesic drugs, we recently developed a gait analysis system, which provides an index of pain severity based on walking stride disturbance. Using this system, we evaluated the therapeutic effect of topical nonsteroidal anti-inflammatory drugs (NSAIDs) in rat models of acute inflammation. We found that the gait analysis system is more sensitive than conventional evaluation methods, such as measurement of swelling or analgesia, which indicated the superiority of our system for drug screening. The approach also indicated that ketoprofen is superior to other NSAIDs for providing pain relief because of its higher skin permeability. To the best of our knowledge, this is the first report demonstrating the effectiveness of topical NSAIDs in experimental animal models of acute inflammation.