title: Thermodynamics of binding of neutral molecules to sulfobutyl ether beta-cyclodextrins (SBE-beta-CDs): the effect of total degree of substitution.
abstract: OBJECTIVE
  To understand the role of degree of substitution on binding of molecules to beta-Cyclodextrins (beta-CDs) with varying degrees of sulfobutyl ether (SBE) substitution.
  
  
  METHODS
  Using UV spectroscopy, complexation constants of molecules to SBE-beta-CDs were estimated as a function of temperature, allowing for calculation of thermodynamic parameters, including the enthalpy and entropy of binding.
  
  
  RESULTS
  Binding constants of various molecules to SBE-beta-CDs did not show a uniform trend to total degree of SBE substitution. However, a distinct pattern was observed with the enthalpy and entropy of complexation. The results showed the complexation of substrates to SBE-beta-CDs to be more entropy-favored as the number of SBE groups increased. This favorable entropy of interaction was compensated by a less favorable enthalpy of interaction.
  
  
  CONCLUSIONS
  Enthalpy and entropy of complexation provided additional insight into the role that the alkylsulfonate groups may play in the complexation of molecules with SBE-beta-CDs.
authors.affiliation: Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence 66047, USA.
authors.forename: V
authors.initials: V
authors.lastname: Zia
authors.forename: R A
authors.initials: RA
authors.lastname: Rajewski
authors.forename: V J
authors.initials: VJ
authors.lastname: Stella
mesh_terms: D003505:Cyclodextrins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics; D047392:beta-Cyclodextrins
chemical_list: D003505:Cyclodextrins; D047392:beta-Cyclodextrins; C093196:SBE4-beta-cyclodextrin