Diclofenac non-steroidal anti-inflammatory agent (NSAID) with antipyretic and analgesic actions. It is used to relieve pain, swelling (inflammation), and joint stiffness. As side effects, it can cause nausea, heartburn, constipation, headache, drowsiness, and dizziness. Primesep 200, a reverse phase column, contains embedded acidic ionizable groups and can retain Diclofenac. The method is UV compatible and can be used as a general approach for analyzing similar compounds.