Chemical and Pharmaceutical Bulletin · 1970 · 20 citations · 0 references
PharmacyBiochemistryPharmacologyAntimicrobial PharmacologyChemical KineticsStructure-activity RelationshipsConcentration-effect RelationshipsEnzyme KineticsPka DeterminationQuantitative Structure-activity RelationshipsAcid Dissociation ConstantsBacteriostatic ActivityBacteriostatic AgentsBiological Activity FeaturesConcentration-dependent ActivityEscherichia ColiMinimum Bactericidal ConcentrationPka Calculations
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 pKa, equations of the relation of pKa to bacteriostatic activity of sulfonamides against Escherichia coli are proposed. The optimal acid dissociation constant, pKa0, of sulfonamides which are active at a minimum concentration is calculated. pKa0 and the minimum bacteriostatic concentration are found to change with changes of pH of culture media.