Thermodynamic and spectroscopic investigation of the molecular interactions among vitamin B5, calcium salt, and cyclodextrins in aqueous media

The pharmaceutical industry aims to enhance drug development processes by gaining a deeper understanding of the physiochemical properties of drug molecules. This study provides a comprehensive analysis of the volumetric and compressibility properties of the drug, calcium-D-pantothenate (CDP) in aqueous solutions of cyclodextrins (beta-CD/HP-beta-CD). By measuring the density and speed of sound, we have evaluated various parameters, including apparent molar volume, compressibility, and their corresponding infinite dilution parameters. In addition to this, positive transfer parameters such as Delta trVos,phi and Delta trKos,phi of solute provide insights into solute-co-solute and solute-solvent interactions. Also, Hepler's constant offers valuable information on the structure-breaking characteristics of the studied drug in cyclodextrin medium. The decrease in molar conductance of the binary system after adding cyclodextrin supports our theoretical observation from volumetric and compressibility studies. Positive values of activation energy favor spontaneity and the solubilization process. Furthermore, the 1H NMR study demonstrates that the beta-CD molecule interacts more strongly with CDP molecules as compared to HP-beta-CD.