Molecular interactions studies of doxycycline hyclate in water, aqueous L-phenylalanine and glycyl glycine at different temperatures by using volumetric, ultrasonic and viscometric parameters

摘要

The density, sound velocity and viscosity of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine have been determined at different temperatures (305.15, 310.15, 315.15 and 320.15) K. The calculated values of partial molar volume (V-phi(o)) standard partial molar volume of transfer (Delta V-tr(phi)o) partial molar adiabatic compressibility (kappa(o)(phi,s)) and partial molar adiabatic compressibility of transfer (Delta(tr)kappa(o)(phi,s)) for doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine infer the dominance of ion-hydrophilic interactions over hydrophobic-hydrophobic interactions. The Jones-Dole viscosity B-coefficient, viscosity B-coefficient of transfer (Delta trB), free energy of activation of viscous flow per mole of pure solvent (Delta mu(o)(1)*) and solute (Delta mu(o)(2)*) respectively, activation entropy (Delta S-2(o)*) and activation enthalpy (Delta H-2(o)*) of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine also have been calculated using viscosity data. The structure making and breaking behaviour of doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl cm glycine are obtained from the values of Hepler's constant i.e. (delta V-2(phi)o/delta T-2) and (DB/DT). The presence and absence of caging effect has been studied with the help of partial molar adiabatic expansibility (E-phi(o)). The isobaric thermal expansion coefficient (alpha(o) = E-phi(o)/V-phi(o) ), intermolecular free length and acoustic impedance for doxycycline hyclate in water, aqueous solution of L-phenylalanine and aqueous solution of glycyl glycine also have been determined.