ABSTRACT
Objective To study the interaction of γ-cyclodextrin (-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 and1HNMR. 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) X 107 L/mol, HS-7 and vecuronium being (5. 80 + 1. 83) X 106 L/mol, Sugammadex and rocuronium being (1. 04+0. 34) X 107 L/mol, Sugammadex and vecuronium being (2. 53 + 1. 07) X 106 L/mol, and γ-CD and rocuronium being (2. 84 + 3. 41) X 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 y-CD and rocuronium being 6. 93 X 104 L/mol, and of γ-CD and vecuronium being 5. 17 X 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.