Thermodynamic aspects of solubility, solvation and partitioning processes of some sulfonamides

摘要: Abstract The thermodynamic aspects of sublimation processes three sulfonamides with the general structures C6H5–SO2NH–C6H4–R (R = 4-NO2) and 4-NH2–C6H4–SO2NH–C6H4–R (R = 4-NO2; 4-CN) were studied by investigating temperature dependence vapor pressure using transpiration method. These data together those obtained earlier for (R = 4-Cl) (R = 4-Cl; 4-OMe; 4-C2H5) analyzed compared. A correlation was derived between Gibbs free energies sum H-bond acceptor factors molecules. Solubility compounds in water, phosphate buffer pH 7.4 n-octanol (as phases modeling various drug delivery pathways) investigated corresponding functions calculated as well. Thermodynamic characteristics solvation evaluated. Also this case a solubility/solvation energy values observed. For substituents at para-position transfer from one solvent (water or buffer) to diagram method combined analysis enthalpic entropic terms. Distinguishing enthalpy entropy, is possible through present approach, leads insight that contribution these terms different molecules (entropy- enthalpy-determined). Thus, contrast interpretation only (extensively used pharmaceuticals form partition coefficient, log P), process provides additional mechanistic information. This may be important further evaluation physiological distribution provide better understanding biopharmaceutical properties drugs.