Volumetric and ultraacoustic properties of sodium salts of ibuprofen/diclofenac drugs in aqueous and aqueous-β-cyclodextrin solution

Abstract

Present paper reports the study of inclusion complex formation between two non-steroidal anti-inflammatory drugs namely sodium ibuprofen and diclofenac sodium in water and aqueous-β-cyclodextrin solutions through thermodynamic properties like the standard partial molar volumes and the standard partial molar compressibility at 303.15, 308.15 and 313.15 K and at atmospheric pressure. For this, the densities and ultrasonic velocities of ternary sodium ibuprofen/diclofenac-β-cyclodextrin-water mixtures were measured and used for the calculation of apparent molar volume (V2,ϕ) and apparent molar compressibility (κs,2,ϕ). The concentration dependence of apparent properties has been fitted to standard relations and corresponding the standard partial molar volume (V2o) and the standard partial molar compressibility (κs,2o) and respective solute-solute interaction parameters Sv and Sk were graphically determined. The standard transfer volumes (ΔtrV2o) and standard transfer compressibility (Δtrκs,2o) were also computed and these properties have been interpreted in terms of drug hydration, inclusion complex formation, and different interactions involved. The sign of Sv and Sk revealed the weakening of solute–solute interactions in presence of cosolute β-cyclodextrin. Solubilization of hydrophobic parts, expulsion of water from hydrophobic cavity of β-cyclodextrin and inclusion complex formation of these drugs with β-cyclodextrin has been confirmed from partial molar volume and transfer properties.