Development of thiolated xanthan gum-stearylamine conjugate based mucoadhesive system for the delivery of biochanin-A to melanoma cells

Recently, instead of creating new active compounds, scientists have been working to increase the bioavailability and residence time of existing drugs by modifying the characteristics of the delivery systems. In the present study, a novel mucoadhesive bioconjugate (SN-XG-SH) was synthesized by functionalizing a polysaccharide xanthan gum (XG) with cysteamine hydrochloride (CYS) and a lipid stearylamine (SN). FTIR, CHNS and 1H NMR studies confirmed the successful synthesis of SN-XG-SH. Mucoadhesion of the thiolated XG was enhanced and evaluated by different methods. Disulfide bond formation between thiolated XG and skin mucus enhances mucoadhesive behavior. The mucoadhesive bioconjugate was used to prepare nanoparticles for the delivery of hydrophobic biochanin-A (Bio-A) for the treatment of melanoma. The thiolated xanthan gum nanoparticles also demonstrated high drug entrapment efficiency, sustained drug release, and high storage stability. The drug loaded nanoparticles (Bio-A@TXNPs) significantly improved the cytotoxicity of Bio-A against human epidermoid cancer cells (A431 cells) by inducing apoptosis and changing mitochondrial membrane potential. In conclusion, thiolation of XG improves its mucoadhesive properties and prolongs the release of Bio-A. Thus, thiolated XG conjugate has a high potential for use as a bioadhesive agent in controlled and localised delivery of drugs in different skin diseases including melanoma.