Solute-solvent and solute-solute interactions of ibuprofen in aqueous and in aqueous solutions of urea, sodium salicylate and nicotinamide by volumetric and interferometric techniques

Abstract

Solubility of drugs in aqueous media is a real issue for scientists and a lot of work is going on to resolve the issue. The same is the case for ibuprofen, which is a derivative of propionic acid and belongs to the NSAIDs family having low solubility in pure water. Therefore, its solubility has been investigated in the presence of hydrotropic agents like urea, sodium salicylate and nicotinamide at four different temperatures ranging from 298.15K to 313.15K at 5K interval. The values of density (d) and sound velocity (U) have been measured in aqueous ibuprofen and ibuprofen + aqueous solution of urea, sodium salicylate and nicotinamide separately in five different concentrations. Densities of these solutions were measured at the above said four temperatures. The ultrasonic velocities (U) have been measured at 298.15K only. Experimental density data have been used to estimate various important parameters, such as apparent molar volume(Vɸ), limiting apparent molar volumeVɸ0, apparent molar expansibility (Eɸ) and limiting apparent molar expansibility (Eɸ0). Further, from the ultrasonic data, different thermo-acoustical parameters, such as isentropic compressibility (KS), apparent molar isentropic compressibility (Ks,ɸ) and acoustic impedance (Z), have been evaluated, and discussed in the light of solute-solute and solute-solvent interactions. Solubility parameters were found to be useful for selecting a suitable hydrotropic agent in drug dissolution.