Bioadhesive dermal patch as promising approach for improved antibacterial activity of bioactive compound of Zingiber cassumunar Roxb in ex vivo Staphylococcus aureus skin infection model

Infected burn injury has become a significant challenge among skin health problems. Recently, the use of a natural product, as an antibacterial alternative, has increased, particularly in the management of skin infections.Zingiber cassumunar Roxb. has been reported to possess a high amount of curcumin, showing an excellent anti- bacterial activity against Staphylococcus aureus, a bacterium associated with skin infections. With respect to the selection of drug dosage form, the use of a bioadhesive patch could be beneficial as this system can easily adhere to the infected site in the skin. Here, we present the development of bioadhesive patches containing Zingiber cassumunar Roxb. extract with different types of bioadhesive polymers, namely HPMC, NaCMC, chitosan and Carbopol. The characterization results indicated that the patches were uniform in their drug content, weight and thickness, indicating the reproducibility of the method used. Importantly, the patches were found to have excellent folding endurance values, which were more than 300 times, with surface pH values close to skin pH. The ex vivo dermal delivery showed that among the four bioadhesive polymers studied, HPMC and NaCMC were 1.3–2 times better than chitosan and Carbopol in terms of delivery of curcumin. Essentially, more than 80% of bacterial burdens were killed following the application of HPMC and NaCMC patches in an ex vivo Staphylococcus aureus infection model in rat skin. However, considering that HPMC patches showed lowest bioadhesion prop- erty, patches prepared from NaCMC were considered as the optimized formulation. To conclude, this work shows a promising delivery approach for a natural product in the treatment of the skin infections.