STUDIES ON CERTAIN SULFA DRUGS PARTITION IN LIQUID/LIQUID BIPHASE SYSTEMS. Ⅱ CORRELATION BETWEEN THE SULFONAMIDES CHARACTERISTICS AND THOSE OF THE SOLVENTS EMPLOYED

摘要

The possibility of correlating some of the characteristics (hydrophobicity, acidity constant, molecular mass and melting point) of sulfonamides (4-amino-N-(4,6-dimethyl-2-pyrimidinyl) benzensulfonamide, 4-amino-N-(5,6-dimethoxy-4-pyrimidinyl) benzensulfonamide, 4-amino-N-(5-methyl-3-isoxazolyl) benzensulfonamide, 4-amino-N-(3,4-dimethyl-5-isoxazolyl) benzensulfonamide) with some of the characteristics (polarity, dielectric constant, density, viscosity, surface tension and the dipol moments) of organic solvents (n-butanol, i-butanol, n-octanol, 1,2-dichloroethane, methylenechloride chloroform, benzene, toluene, and n-hexane) was studied in the case of water/organic solvents partition for the four sulfa drugs by means of a multilinear regression analysis. This study has evidenced that: a) the relevant characteristics of sulfonamides are the acidity (K_a) and the hydrophobic constant (Σf) calculated from sum fragments; b) the most significant characteristics of the solvents are the dielectric constant (ε) and the surface tension (γ). The results obtained afford a logical selection of the working conditions in the extraction from water in different organic solvents of the sulfonamides.