Biological Activity of Drugs. X. Relation of Structure to the Bacteriostatic Activity of Sulfonamides. (1)

Abstract

Based on the experimental observations that the concentrations of ionized and unionized molecules of sulfonamides at the bacteriostatis are linearly related to the drug's pK_a, equations of the relation of pK_a to bacteriostatic activity of sulfonamides against Escherichia coli are proposed. The optimal acid dissociation constant, pK_a⁰, of sulfonamides which are active at a minimum concentration is calculated. pK_a⁰ and the minimum bacteriostatic concentration are found to change with changes of pH of culture media.