Apparent molar volume and adiabatic compressibility studies of aqueous solutions of some drug compounds at 25 °C

Abstract

MOHAMMAD IQBAL and R. E. VERRALL. Can. J. Chem. 67, 727 (1989). Apparent molar adiabatic compressibilities and volumes of aqueous solutions of the following drugs (sodium salicylate, methyl orange, L-tryptophan, phenol, and the hydrochloride salts of propranalol, procaine, pilocarpene, and ephedrine) have been calculated from high precision density and sound velocity measurements at 25°C. These drugs are considered important in several biochemical phenomena such as anomalous protein binding, anesthesia, or unique structure-activity relationship and this study is part of a comprehensive investigation of drug-protein interactions in biological systems. The data are qualitatively interpreted in terms of solute-solvent and solute-solute interactions. Some plausible modes of drug hydration are discussed with particular reference to the structure of the drug molecules. The adiabatic compressibility shows a strong correlation with the hydrational behaviour of the solute molecule and appears to be sensitive to the structural features of the solute, such as shape, size, branching, and presence of aromatic rings. It is argued that these aspects are important in terms of considering the geometrical fit of the solute into the ordered form of the aqueous solvent surrounding these solutes.Key words: apparent molar adiabatic compressibilities, apparent molar volumes, hydration of drugs.MOHAMMAD IQBAL et R. E. VERRALL. Can. J. Chem. 67, 727 (1989). Utilisant des mesures de haute prtcision de la densitt ainsi que de la vitesse du son, a 25"C, on a calculC les volumes et les compressibilitCs molaires apparentes de solutions aqueuses des drogues suivantes: salicylate de mCthyle, orange de mtthyle, L-tryptophane, phCnol ainsi que les chlorhydrates de la propanolamine, de la procaine, du piloc&ne et de 1'CphCdrine. Ces drogues sont souvent considCrtes comme importantes dans plusieurs phenomknes biochimiques tels que la liaison anormale des protkines, I'anesthCsie ou une relation structure-activitC particulikre; cette ttude a Ct C rCalisCe dans le cadre d'un examen gtntral des interactions drogues-protCines dans des systkmes biologiques. Qualitativement, on interprkte ces donnees en fonction d'interactions solute-solvant et solutC-solute. On discute de quelques modes plausibles pour l'hydratation des drogues et en particulier la structure des drogues. I1 existe une importante corrtlation entre les compressibilitCs adiabatiques et les possibilitts d'hydratation des moltcules en solution vis-a-vis de I'hydratation; de plus, elles semblent Stre sensibles aux caractkristiques structurales du solutt, comme la forme, la grosseur, les ramifications et la presence de noyaux aromatiques. On suggkre que ces aspects sont importants lorsqu'on veut insCrer ces solutCs dans la forme ordonnte du solvant aqueux qui entoure ces solutCs.

Partial molar volume of mefenamic acid in alcohol at temperatures between T=293.15 and T=313.15 K

“…The partial molar volume, pressure derivative of Gibbs energy, is a useful parameter for interpreting solute-solvent interactions. 5,6 Comparison of the volume of the system with those of its components can assess gross changes in the volume of the system because it is an additive property. In addition, volumetric data can also be interpreted in terms of molecular interactions within the system.…”

“…Various molecular processes in solutions such as electrostriction, 7 hydrophobic hydration, 8 micellization and co-sphere overlap during solute-solute interactions have been interpreted, to a large extent, from the partial molar volume data of many compounds including amino acids, peptides and also some drug compounds. 5 Mefenamic acid is known as an antipathologistic analgesic and provides relief of mild to moderate pain, especially pain after surgery and fever. Mefenamic acid is known to strongly bind to the plasma protein.…”

Volumetric and Acoustic Behavior of Sodium Cyclamate in Aqueous System from 293.15 K to 318.15 K

“…The greater the number of water molecules interacting with the solute molecules the greater will be the hydration number of the solute [30]. The compressibility hydration number indirectly represents the solution behavior.…”

Ultrasonic Speed, Density, Viscosity and Associated Acoustical Parameters of Chloroform Solutions of Symmetric Double Schiff Bases at 308.15K

“…ionic or covalent, charge-transfer, hydrogen bonding, ionic-dipole interaction, hydrophilic interaction. Density, viscosity and ultrasonic speed data are helpful in analyzing such physico-chemical molecular interactions [9].…”