Date of Award

1971

Degree Type

Dissertation

Degree Name

Doctor of Pharmacy (PharmD)

First Advisor

Anthony N. Paruta

Abstract

The solubility of four sulfonamides in normal alcohols and in buffered aqueous systems was determined at 25°, 30° and 37° Centigrade. The solubility pathway for a nonelectrolyte solute can be described by a process which follows a two -step sequence: Solid/solute -1- liquid/solute-2-solute in solution The pathway was assumed operative for the solute-solvent systems studied, and was used as a basis for the interpretation of the thermodynamic quantities associated with the dissolution process. Heats of solution and their corresponding entropies were evaluated by semilog plots of mole fraction solute concentration versus reciprocal temperature (degrees Kelvin) and these solubilities were found to increase with increasing temperature. Quantitative determination of the solute concentrations was achieved using spectrophotometric analysis and these data were subjected to statistical evaluation. Partition coefficient data were determined for a particular sulfonamide, sulfadiazine, in an attempt to assess the value of these quantities. All partitioning data were determined in a constant temperature environment, and the solute concentration of the equilibrated systems was measured using a practical method of determining the ionization constants for poorly soluble weak electrodes. These data were of limited usefulness, however, with respect to theoretical considerations of solute-solvent interactions.

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