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Microionization constants of sulphonamides.
1Faculty of Pharmaceutical Sciences, University of Tokushima, Scho-machi 1, Tokushima 770, Japan.
Talanta
|March 1, 1980
Summary
This study determined ionization and thermodynamic parameters for twelve sulfonamides using potentiometry and spectrophotometry. Results provide insights into sulfonamide behavior across different temperatures and pH levels.
Area of Science:
- Analytical Chemistry
- Physical Chemistry
- Medicinal Chemistry
Background:
- Sulfonamides are a vital class of drugs with complex ionization behavior.
- Understanding their thermodynamic and ionization properties is crucial for drug formulation and efficacy.
Purpose of the Study:
- To determine the macro- and microionization constants of twelve commercial sulfonamides.
- To investigate the thermodynamic parameters influencing sulfonamide ionization.
- To calculate species distribution as a function of pH for different sulfonamide types.
Main Methods:
- Potentiometric titration at 15, 25, and 35°C.
- Spectrophotometry at 25°C in 0.1 M NaClO(4) aqueous solution.
- Edsall method combined with tristimulus colorimetry for micro- and tautomeric constants.
Main Results:
- Macroionization constants and thermodynamic parameters were successfully determined for twelve sulfonamides.
- Microionization and tautomeric constants were calculated using the Edsall method and colorimetry.
- Species distribution curves as a function of pH were generated for the studied sulfonamides.
Conclusions:
- The study provides comprehensive ionization and thermodynamic data for commercial sulfonamides.
- These data are essential for predicting sulfonamide behavior in various physiological and formulation conditions.
- The findings contribute to a deeper understanding of sulfonamide chemistry and pharmacology.
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