Interactions of Drug Doxycycline Hyclate with Galactitol in Aqueous Solutions at Different Temperatures by Volumetric and Acoustic Methods

Abstract

Abstract The experimental values of density, ρ and speed of sound, u of doxycycline hyclate drug (0.002–0.014) mol kg−1 in water and (0.1, 0.2 and 0.4) mol kg−1 of aqueous galactitol solutions at temperatures T = (303.15, 308.15 and 313.15) K and at atmospheric pressure have been reported in the present communication. From the experimental values, various derived parameters such as apparent molar volume (Φ V), apparent molar isentropic compression (Φ K), limiting apparent molar volume ( Φ v o $\phi_{\text{v}}^{\text{o}}$ ), limiting apparent molar isentropic compression ( Φ K o $\phi_{\text{K}}^{\text{o}}$ ), limiting apparent molar volume of transfer (Δ Φ V O $\phi_{\text{V}}^{\text{O}}$ ), limiting apparent molar isentropic compression of transfer (Δ Φ K O $\phi_{\text{K}}^{\text{O}}$ ), limiting apparent molar expansibility ( Φ E o $\phi_{\text{E}}^{\text{o}}$ ), thermal expansion coefficient (α) and acoustic parameters like isentropic compressibility ( κ S ) $({{\kappa}_{\text{S}}})$ , intermolecular free length (Lf), and specific acoustic impedance (Z) were calculated. The structure-making behaviour of DH in aqueous galactitol solution was determined on the basis of Hepler’s Equation i.e. on the basis of sign of ( d 2 Φ V O d T 2 ) P ${\left({\frac{{{{\text{d}}^{2}}\phi_{\text{V}}^{\text{O}}}}{{{\text{d}}{{\text{T}}^{2}}}}}\right)_{\text{P}}}$ . The various derived parameters were utilised to interpret the molecular interactions i.e. solute–solute and solute–solvent existing in the studied system.