A nanoformulation that includes loaded nanoparticles. Each nanoparticle includes a modified chitosan polymer encapsulating at least one vitamin D derivative, at least one vitamin D metabolite, or combinations thereof. The modified chitosan polymer includes chitosan covalently linked to at least one entity selected from the group consisting of fatty acids (omega-3-fattay acids), amino acids, deoxycholic acid, alginate, arginine-alginate, hyaluronic acid, collagen, collagen-hydroxyapatite, poly(lactic-co-glycolic acid) (PLGA), and combinations thereof. A structure includes a medium and the nanoformulation, wherein the nanoparticles are dispersed in the medium. A method of using the nanoformulation to treat a disorder and improve efficacy of current therapies where resistance develop in a patient includes administering to the patient a therapeutically effective amount of the nanoformulation for treating the disorder. A nano-cosmetic formulation, comprising a cosmetic includes the nanoformulation, wherein the modified chitosan polymer encapsulates the at least one vitamin D derivative, and wherein the at least one vitamin D derivative encompasses 0.1 to 20.0 wt % of the nano-cosmetic formulation's total weight.