Features of Complex Formation of Native and Polymeric β-Cyclodextrins with Sulfasalazine

The complex formation of sulfasalazine with native and polymeric β-cyclodextrins in buffer solutions with a physiological pH value was studied using isothermal saturation and 1 H NMR methods. It was found that sulfasalazine forms two types of complexes in reactions with above cyclodextrins, but only the formation of inclusion complexes determines the observed increase in drug solubility, which is more pronounced in the presence of polymeric β-cyclodextrin. The complex formation with β-cyclodextrin and its polymeric derivative leads to a decrease in the coefficients of sulfasalazine permeability through the model membrane, which is determined by both the stability constant of the complexes and their ability to pass through the membrane.