Abstract
Indian Propolis, a resin-like substance obtained from plants and modified by bees is a blend of various natural components and a potential candidate for topical application for chemoprevention of skin cancer. In the present study, the potential role of propolis loaded ethosomal transgel for the chemoprevention of skin cancer was investigated. Ethosomal vesicular systems were optimized by varying the proportions of lecithin and ethanol taking vesicle size, polydispersity index (PDI) and entrapment efficiency as dependent variables. The vesicles were found to be unilamellar spherical shaped entities with size varying from 100 nm to 300 nm and entrapment efficiency in a range of 48% to 84%. The permeation and extent of penetration of the optimized formulation were evaluated by Franz diffusion cell and Confocal scanning laser microscopy (CSLM) respectively. It showed a sustained mode of release and remarkable penetration capacity of vesicles (133µm) as compared to hydroethanolic solution of the drug. Histopathological evaluation of the formulation treated skin revealed the interaction of vesicles with the skin which was further supported by FTIR analysis reflecting the mechanism of vesicle permeation via skin. Propolis loaded ethosomal vesicles were then incorporated into carbopol gel and characterized using a texture profile analyzer. The optimized gel so obtained was then finally evaluated for its chemo preventive activity by exposing Swiss albino mice to UVB radiation. The study indicated the possible use of propolis for the prevention of skin cancer through a deep-rooted delivery via ethosomal system eventually circumventing the problem of poor penetrability of topical preparations.
Keywords: cancer chemoprevention, ethosomes, propolis, gel, reactive oxygen species, transdermal, UVB.