Improved transdermal delivery of morin efficiently inhibits allergic contact dermatitis

The skin is an important site for local or systemic application of drugs. However, most of the drugs have poor permeability through the skin's outermost layer, stratum corneum. The aim of this study was to develop a method to enable transdermal delivery of morin (3, 5, 7, 2, 4-pentahydroxyflavone), which is a poorly water-soluble drug with anti-inflammatory properties obtained from natural products. Morin phospholipid complex (MPC) was prepared and then loaded in Carbopol 940 hydrogel (MPC-gel), which can significantly increase the transdermal flux of morin based on the in vitro skin penetration data presented in this paper. To further enhance permeation, different compositions of penetration enhancers were dispersed in the gel and screened. After applied onto the mouse skin, MPC-gel showed apparent reduction of ear swelling in 2, 4-dinitrofluorobenzene (DNFB)-induced allergic contact dermatitis (ACD). Further determination of cytokines levels, histopathological analysis and T lymphocytes proliferation indicates that the MPC-gel is potent enough to reduce the inflammatory response mediated by the DNFB in ACD mice model. Collectively, we anticipate that such an approach may provide a new treatment for topical ACD.