Physicochemical Characterization of 2‑Hydroxybenzophenone with β‑Cyclodextrin in Solution and Solid State

M.I. SANCHO; M.G. RUSSO; M.S. MORENO; E. GASULL; S.E. BLANCO; G.E. NARDA

JOURNAL OF PHYSICAL CHEMISTRY B - (Print)

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 119 p. 5918 - 5925

1520-6106

The characterization of the inclusion complex between 2-hydroxybenzophenone (2OHBP) and β-cyclodextrin (βCD) in the solid state was performed using Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (PXRD), differential scanningcalorimetry (DSC), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The apparent formation constant of the complex was determined by phase solubility diagrams and liquid chromatography (HPLC) at different temperatures. The formation of the inclusion complex induced slight shifts in the FTIR spectrum while byPXRD a new crystalline phase was observed. TEM studies revealed that the complex forms aggregates of nanometric size. The inclusion complex showed a higher solubility in the tested dissolution media than free 2OHBP. Moreover, the freeze-dried solid complex exhibits a higher thermal stability than the solid free drug. The thermodynamic analysis allowed us to conclude that the encapsulation process is endothermic in water and exothermic in methanol−water.