Diclofenac transdermal patch versus the sustained release tablet: A randomized clinical trial in rheumatoid arthritic patients

Purpose: To prepare and characterize transdermal films of diclofenac diethanolamine as a safer and more effective alternative than the sustained release (SR) tablet equivalent for prolonged relief from pain and inflammation in arthritis.
Methods: Transdermal films of diclofenac were prepared using sodium carboxymethyl cellulose and polyvinyl pyrrolidone K30, with turpentine oil and sesame oil as penetration enhancers. The films were characterized for physicochemical properties and for ex vivo permeation in a randomized clinical trial (RCT) for analgesic activities in arthritic patients.
Results: The transdermal films were uniform in weight and thickness, flat, with high drug content (94.40 ± 1.04 to 98.62 ± 1.08 %) and with high folding endurance (149 ± 9.09 to 192 ± 10.12). Drug permeation through excised rat abdominal skin was prolonged. Films containing penetration enhancers showed higher ex vivo drug permeation than those without the enhancer; furthermore, drug permeation increased with increase in the concentration of enhancer. The films were non-irritating to the skin. In RCT, F3 (containing turpentine oil, 1 %v/w) decreased the pain score from 9.87 ± 1.14 to 4.94 ± 0.78 units, compared with the SR tablet (once daily) which decreased pain from 9.59 ± 0.42 to 6.49 ± 1.20 units, 48 h post-administration. Turpentine oil showed better permeation enhancement than sesame oil in the transdermal films.
Conclusion: Transdermal films of diclofenac, formulated with permeation enhancers, may have greater therapeutic advantages over conventional oral tablets in terms of prolonged release and improvement of patient compliance in rheumatoid arthritis.

Keywords
Analgesic activity; Diclofenac; Permeation enhancer; Rheumatoid arthritis; Transdermal films