Effect of presence of α-cyclodextrin and β-cyclodextrin on solution behavior of sulfathiazole at different temperatures: Thermodynamic and spectroscopic studies

Thermodynamic and spectroscopic properties of α-cyclodextrin and β-cyclodextrin in aqueous solution sulfathiazole have been investigated by volumetric, ultrasonic measurements at T = (288.15-308.15 K) along with absorption spectra and fluorescence studies. The apparent molar volumes at infinite dilution, Vϕ0 and the apparent molar isentropic compression at infinite dilution Kϕ,S0, have been calculated from density and speed of sound data. Furthermore, partial molar volumes of transfer, ΔtrVϕ0, partial molar isentropic compression of transfer, ΔtrKϕ,S0, apparent molar expansivity, Eϕ0, Hepler's constant values, ∂Eϕ0∂TP and thermal expansion coefficient, α have also been evaluated to support the conclusions obtained from the volumetric and acoustic studies. These parameters are helpful to study the solvation behavior and various interactions present in the ternary solutions of (α-cyclodextrin/β-cyclodextrin + sulfathiazole + water). Further, absorption and emission spectra has been recorded for aqueous sulfathiazole solution in α-cyclodextrin to analyze the host-guest interactions. The inclusion complex of sulfathiazole with α-cyclodextrin is investigated by UV-visible spectroscopy and fluorescence. The study indicates that sulpha drug forms 1:1 inclusion complexes with α-cyclodextrin.