DFT study of bismuth subsalicylate adsorption on bow-tie dendrimer nanocarrier as drug delivery agents

Ulcerative colitis is a subtype of inflammatory bowel disease with symptoms that progress from mild to severe. It has multiple treatment options, but requires effective monotherapy for its treatment. In this context, a theoretical study was conducted on the interaction of bismuth subsalicylate (BSS) with a bow-tie (DP) polyester dendrimer for use as a nanocarrier. The reactivity indices and frontier molecular orbitals indicate that these systems can interact. The complexes were formed through the interaction of the oxygens of the dendrimer with the bismuth of the BSS and also by hydrogen bonding. The Delta G values were > 0 kcal mol(-1), which indicated that the systems are not spontaneous, although the values of adsorption energies (E-ads) and enthalpy showed values < 0 kcal mol-1, showing that interactions can occur. Topological analyses based on the quantum theory of atoms in molecules allowed the characterization of molecular interactions. The interactions of Bi with O were partially covalent, and the hydrogen bonds (O...H) were classified as weak or moderate. Finally, the interactions between the nanocarrier and the drug had positive results, which can be attributed to the polyester dendrimer being a good nanocarrier for the release of BSS.