Densities and ultrasonic velocities of promethazine hydrochloride drug were measured in aqueous and aqueous-glycine/L-proline solutions at (303.15, 308.15, 313.15) K and 0.1 MPa. Apparent molar volumes and compressibilities, isentropic compressibilities, specific acoustic impedance and relative association of drug in studied solutions were calculated. The linear dependence of apparent volumes and molar isentropic compressibilities over the drug concentration has been utilized to determine its limiting partial molar volumes and compressibilities in different aqueous media.Standard transfer volumes and compressibilities from water to aqueous-amino acid solutions were calculated. Results of standard transfer volumes and compressibilities indicated drug-amino acidsinteractions.These interactions are found to be stronger in aqueous 0.05 mol·kg -1 Gly/Pro solutions in molecular monomer and micellar form of the drug. Enhanced volumes and compressibilities with temperature confirmed loosened hydration sphere of drugs due to weak drug-water interactions.
Pawar et al. (Fri,) studied this question.