Rationale and evidence for the incorporation of heparin to the diclofenac epolamine medicated plaster

The nonsteroidal anti-inflammatory drug (NSAID) diclofenac epolamine (DHEP) formulated as a topical patch has demonstrated efficacy and safety in the localized treatment of acute pain from minor strains, sprains, and contusions, and for epicondylitis and knee osteoarthritis. The glycosaminoglycan heparin enhances the activity of topical NSAIDs formulated as a medicated plaster, even in the absence of any significant release of heparin. Therefore, DHEP Plus, a new formulation of the DHEP medicated plaster containing a small amount of heparin sodium as excipient has been developed. Methods: We reviewed the pivotal and supportive studies of the clinical development program of the new patch and evaluated the role of heparin as an enhancer in the treatment of localized pain/inflammation of musculoskeletal structures, associated with post-traumatic and/or rheumatic conditions. Results: The data were consistent with the concept that heparin increased the clinical activity of the DHEP Plus medicated plaster versus the reference DHEP medicated plaster through improved bioavailability due to enhanced movement of diclofenac from the plaster. Both DHEP formulations have the same dissolution profile, indicating that heparin does not change the physical and chemical characteristics of the plaster. Permeation testing showed that heparin is not released from the DHEP Plus medicated plaster. Efficacy studies showed that the DHEP Plus medicated plaster was significantly more effective in reducing pain than the reference marketed DHEP medicated plaster. Conclusions: The benefit/risk assessment of DHEP Plus 180 mg medicated plaster is favorable, with a safety profile equal to placebo and improved efficacy over the reference marketed DHEP medicated plaster.