Interaction between naproxen and chemically modified beta-cyclodextrins in the liquid and solid state

The complexation between naproxen and some chemically modified beta-cyclodextrins (hydroxyethyl beta-cyclodextrin with average substitution degree per anhydroglucose unit 0.6, 1.0 and 1.6; hydroxyproyl beta-cyclodextrin with average substitution degree per anhydroglucose unit 0.6 and 0.9) was studied using phase-solubility analysis and molecular modelling. The amorphous carriers exhibit similar solubilizing effects and complexing abilities, which are reflected by a comparable increase in drug dissolution rate to about the same extent from equimolar blends with each chemically modified beta-cyclodextrin. X-ray diffractometry and differential scanning calorimetry data indicate a role of the degree of substitution of the carrier in the decrease in crystallinity of naproxen in equimolar blends with chemically modified beta-cyclodextrins.