Spectroscopy study on the interaction of γ-cyclodextrin and its two derivatives with rocuronium and vecuronium

Objective To study the interaction of γ-cyclodextrin(γ-CD) and its two derivatives with rocuronium and vecuronium.Methods The interactions of γ-CD and its two derivatives HS-7,Sugammadex with rocuronium and vecuronium were characterized by Isothermal Titration Calorimetry(ITC),and the thermodynamic constant and the binding constant was determined.The binding constant and inclusion ratio of γ-CD with rocuronium and vecuronium was observed by ultraviolet-visible spectrophotometry; the binding ability of three cyclodextrins with rocuronium and vecuronium was analyzed by nuclear magnetic resonance spectroscopy COSY and1 HNMR.Results The results of ITC showed that HS-7,Sugammadex combined with rocuronium and vecuronium in a 1∶ 1 molar ratio,and γ-CDs combined with rocuronium in a 2∶ 1 molar ratio,with the binding constant of HS-7 and rocuronium being(3.44 ± 2.18) × 107 L / mol,HS-7 and vecuronium being(5.80 ± 1.83) × 106 L / mol,Sugammadex and rocuronium being(1.04 ± 0.34) ×107L / mol,Sugammadex and vecuronium being(2.53 ± 1.07) × 106 L / mol,and γ-CD and rocuronium being(2.84 ± 3.41) × 104 L /mol.The results of ultraviolet-visible spectrophotometry revealed that γ-CDs combined with rocuronium and vecuronium in a 2∶ 1 molar ratio,with the binding constant of γ-CD and rocuronium being 6.93 × 104 L / mol,and of γ-CD and vecuronium being 5.17 × 104 L /mol.The results of nuclear magnetic resonance spectroscopy suggested that the binding ability of HS-7 with rocuronium and vecuronium was stronger than that of Sugammadex and γ-CD.Conclusion The binding ability of HS-7 with rocuronium and vecuronium is stronger than that of Sugammadex and γ-CD,and the three methods used in this study(ITC,ultraviolet-visible spectrophotometry and nuclear magnetic resonance spectroscopy) can characterize the inclusion complex from different perspectives.