The effect of 1-hexyl-3-methylimidazolium salicylate, [HMIm] [Sal] as an ionic liquid form of active pharmaceutical ingredient (API-IL) on the thermodynamic behavior of two simple amino acids, glycine and L-alanine have been investigated. The densities, speeds of sound, viscosities, and refractive indices of the amino acids in the mixtures of ([HMIm][Sal] + water) have been determined at T = 298.15 K. Moreover, the electrical conductivities of the studied API-IL in water and aqueous mixtures of the amino acids have been calculated using the measured specific conductivities. The measured data were utilized to compute the partial molar volume of transfer (Delta V-tra(phi)0), partial molar isentropic compressibility of transfer (Delta(tra)kappa(0)(phi)), viscosity B-coefficient of transfer (Delta B-tra), ion association constant (K-A), and molar refraction (R-D) quantities. The increase in the positive values of Delta V-tra(phi)0 Delta(tra)kappa(0)(phi) and Delta B-tra with an increase in the API-IL concentration indicates that the ion-polar and polar-polar interactions between the API-IL and amino acid are dominant. Besides, the decrease in the K-A values of [HMIm] [Sal] with the addition of amino acid concentration suggests that the formation of ion pair does not proceed spontaneously due to the ions solvated by the zwitterions of amino acid.