Inclusion complex of antiasthmatic compound with 2-hydroxypropyl-β-cyclodextrin: Preparation and physicochemical properties

This work aims at obtaining 2-hydroxypropyl-β-cyclodextrin inclusion complex with an original antiasthmatic compound in buffer solution and solid state with higher solubility and, hence, bioavailability. The compound solubility with different 2-hydroxypropyl-β-cyclodextrin concentrations has been studied by the phase solubility method. The linearity of the phase solubility diagrams is classified as an AL type and indicates the formation of inclusion complexes with 1:1 stoichiometry. The complex stoichiometry has been confirmed by the Job's method. The solubility of the studied compound in buffer has been considerably increased by complexation with 2-hydroxypropyl-β-cyclodextrin. Complexation stability constants and thermodynamic parameters have been calculated. The obtained inclusion complexes in solid state have been studied by the differential scanning calorimetry, Fourier transform infrared spectroscopy and X-ray powder diffraction. The kinetic characteristics of dissolution for the supramolecular complex have been obtained.