Abstract

TORRES, Daniel R. et al. Dissolution enthalpy of sodium sulfacetamide in water: comparison between solution isoperibolic calorimetry and the van't Hoff method. Quím. Nova [online]. 2008, vol.31, n.6, pp. 1455-1459. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422008000600033.

The dissolution enthalpy (ΔH⁰_soln) of sodium sulfacetamide in water was determined by means of isoperibolic solution calorimetry. It was found that ΔH⁰_soln diminishes as the drug concentration increases. Otherwise, the calorimetric values obtained as a function of the drug concentration were significantly different than those predicted by the van't Hoff method. It was demonstrated that the later is not a fully reliable method for the determination of ΔH⁰_soln values in the specific case of highly soluble sodium salts. The observed phenomenon could be explained by the presence of strong solute-solute interactions at high salt concentrations, in addition to solute-solvent and solvent-solvent interactions.

Keywords : sodium sulfacetamide; solution calorimetry; van't Hoff method.