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

Abstract

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<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>), standard partial molar volume of transfer (Δ_tr,V<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>), partial molar adiabatic compressibility (κ<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>,_s) and partial molar adiabatic compressibility of transfer (Δ_tr, κ<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>,_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 (ΔtrB), free energy of activation of viscous flow per mole of pure solvent (Δµ<img src='http://nopr.niscair.res.in/jinfo/oone.gif' border=0>) and solute (Δµ<img src='http://nopr.niscair.res.in/jinfo/oone.gif' border=0>^*) respectively, activation entropy (Δs<img src='http://nopr.niscair.res.in/jinfo/oone.gif' border=0>^*) and activation enthalpy (ΔH<img src='http://nopr.niscair.res.in/jinfo/oone.gif' border=0>^*) 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 glycine are obtained from the values of Hepler’s constant i.e. (δ²V<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>/δT²) and (dB/dT). The presence and absence of caging effect has been studied with the help of partial molar adiabatic expansibility (E<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>). The isobaric thermal expansion coefficient (α^o = E<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>/V<img src='http://nopr.niscair.res.in/jinfo/zerophi.gif' border=0>), 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.