STUDIES ON CERTAIN SULFA DRUGS PARTITION IN LIQUID LIQUID BIPHASE SYSTEMS .2. CORRELATION BETWEEN THE SULFONAMIDES CHARACTERISTICS AND THOSE OF THE SOLVENTS EMPLOYED/

The possibility of correlating some of the characteristics (hydrophobi city, acidity constant, molecular mass and melting point) of sulfonami des (4-amino-N-(4,6-dimethyl-2-pyrimidinyl) benzensulfonamide, 4-amino -N-(5,6-dimethoxy-4-pyrimidinyl) benzensulfonamide, 4-amino-N-(5-metby l-3-isoxazolyl) benzensulfonamide, 4-amino-N-(3,4-dimethyl-5-isoxazoly l) benzensulfonamide) with some of the characteristics (polarity, diel ectric constant, density, viscosity, surface tension and the dipol mom ents) of organic solvents (n-butanol, i-butanol, n-octanol, 1,2-dichlo roethane, 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 s tudy has evidenced that: a) the relevant characteristics of sulfonamid es are the acidity (K-a) and the hydrophobic constant (Sigma f) calcul ated from sum fragments; b) the most significant characteristics of th e solvents are the dielectric constant (epsilon) and the surface tensi on (gamma). The results obtained afford a logical selection of the wor king conditions in the extraction from water in different organic solv ents of the sulfonamides.