The theoretical study of the host-guest complex formed by drug molecule, 4,4-diaminodiphenyl sulfone or dapsone (dap) and β-cyclodextrin(β-CD) was permformed in order to increase the solubility of the drug in question. We used the Density Functional Theory level of theory B3LYP method together with the base set 6-31g (d, p) for obtaining the interaction energies, the analysis of the IR graphs, and subsequent comparison with the experimental data, confirmed the effectiveness of the complexation and the consequent increase of the solubility; the evaluation of the magnetic dipole moment of dapsone before and after the complexation in β-CD was also used as confirmation parameter of the increase of the solubility, beides than, the DFT calculations with solvent effect show that the formation of inclusion is spontaneous and enthalpy driven.