Density (rho) and viscosity (eta) measurements were carried out for 4-aminobutyric acid in 0.0041, 0.0125 and 0.0207 mol.L-1 aqueous salbutamol sulphate at T = 308.15, 313.15 and 318.15 K. The measured values of density and viscosity were used to estimate some important parameters such as apparent molar volume V-phi, limiting apparent molar volume V-phi(0) transfer volume Delta V-phi(0), hydration number n(H), second derivative of infinite dilution of partial molar volume with temperature partial derivative V-2(phi)0/partial derivative T-2, viscosity B-coefficients, variation of B with temperature dB/dT, free energy of activation per mote of solvent Delta mu(0)(1)* and solute Delta mu(0)(2)*, activation entropy Delta S-2(0)* and activation enthalpy Delta H-2(0)* of the amino acids. These parameters have been interpreted in terms of solute-solute and solute-solvent interactions and structure making/breaking ability of solutes in the given solution.