Complexation of sodium picosulphate with beta cyclodextrin: NMR spectroscopic study in solution

Sodium Picosulphate (SPL) is a synthetic drug, widely used for thorough evacuation of the bowel, usually for patients who are preparing to undergo a colonoscopy. Cyclodextrins (CDs) are chiral, truncated cone shaped, cyclic oligosaccharides that can encapsulate a variety of drug molecules into inclusion complexes, thereby increasing their stability and solubility. ¹H NMR spectroscopic studies showed the inclusion complexation between β-CD and SPL, based on the upfield shift changes in the β-CD cavity protons (H-3′ and H-5′) and downfield shift changes in the guest (SPL) protons. The structure of inclusion complexes was determined by 2D ROESY spectral data. The 1:1 stoichiometry and overall association constant (Ka) were determined by using Scott’s plot method to be 450 M^?1.