Effect of β-cyclodextrin on the transfer of N¹-substituted sulfonamides from water to chloroform

Abstract

Solubility data for several A"-substituted sulfonamides in water and in chloroform at 298.15 K and derived Gibbs energies of transfer of these drugs from water to chloroform are reported. Stability constants, derived Gibbs energies, enthalpies and entropies of complexation of these drugs with P-cyclodextrin as obtained by titration microcalorimetry in water are given.Gibbs energy data are used to evaluate the effect of P-cyclodextrin on the transfer of the drug from water to chloroform. It is concluded that the process of transfer of the drug in this solvent system is thermodynamically more favoured in the absence of cyclodextrin.

Solvent and Guest Isotope Effects on Complexation Thermodynamics of α-, β-, and 6-Amino-6-deoxy-β-cyclodextrins

“…Nevertheless, the compensatory enthalpy−entropy relationship has often been observed in both activation and thermodynamic quantities determined for a very wide variety of reactions and equilibria, as pointed out by Leffler half a century ago . Further exemplification and more thorough and critical analyses have been carried out by Leffler and Grunwald, Grunwald and Steel, Exner, Chen, Danil de Namor et al, and Linert et al . It is clear from the original and review articles that widely observed compensatory enthalpy−entropy relationship is a powerful tool to understand and even to predict thermodynamic behavior on the basis of the experimental data already available.…”

Complexation Thermodynamics of Cyclodextrins

“…This extrathermodynamic relationship between Δ H and Δ S was first extensively analyzed and proposed as an empirical rule by Leffler . Further exemplification and more thorough and critical analyses have been carried out by Leffler and Grunwald,215a Grunwald and Steel,215b Exner, Chen, Danil de Namor et al, and Linert et al…”

“…All of the experimental methods mentioned above should be used with the proper precautions and with appropriate skills of the investigator to obtain reliable thermodynamic data. It should be noted that, even within the same article, the equilibrium constants determined by different experimental methods for the same reaction can significantly deviate from one another. , …”

“…Several classes of compounds which can be included in natural α-, β-, and γ-cyclodextrins have been subjected to systematic thermodynamic studies. These cover almost every class of compound such as hydrocarbons, , aliphatic alcohols, ,,,− diols, , amines and acids, cyclohexane derivatives, amino acids, , origopeptides, sugars, phenols, − aromatic amines, azo compounds, − naphthalene derivatives and other aromatic compounds, ,− and various drugs. − However, only a limited number of systematic thermodynamic studies using modified cyclodextrins have been reported. − …”

Pillar[n]arenes and Other Cavitands: Aspects of Complex Thermodynamics

“…[38] The empirical relationship was proposed and analyzed by Leffler and others. [57][58][59][60] A number of experiments led to the derivatization of Eq. 4 from the linear ΔH-ΔS relationship, where β is the isokinetic or isoequilibrium constant.…”