Fructose Chitosan Based Self- Assembled Nanoparticles for Sustained Release of Vitamins and Steroids

Synthetic fructose chitosan (FC) was linked to DL-a-tocopherol, ergocalciferol, diosgenin and two synthetic analogues of brassinosteroids via a succinate linker by carbodiimide coupling in solution. Conjugates with substitution degrees of 5.5 to 39.0% were obtained and used for the sustained release of agrochemicals and potential anticancer drugs. FTIR and proton NMR spectroscopies confirmed the hydrophobic modification of fructose chitosan. Differential scanning calorimetry and wide-angle X-ray diffraction studies of prepared FC conjugates are also presented. The amphiphilic FC-vitamin and FC-steroid conjugates self-assembled in aqueous medium as stable and positively charged nanoparticles of 165 to 213 nm with +30 to +54.2 mV, as revealed using dynamic light scattering. Almost spherical nanoparticles of 40 to 65 nm in dried state were observed by SEM and TEM. Sustained release of linked vitamins and steroids in phosphate buffer saline solution at pH 6.0 was observed over 96 h, while almost constant release rates were perceived during the first 7 to 8 h. Brassinosteroid-N-modified fructose chitosan nanoparticles showed good agrochemical activity. These results indicated that the obtained nanoparticles might be potential drug delivery system of vitamins and steroids for anticancer and agrochemical applications.