Acid-base equilibria in substituted 4-quinolone carboxylic acid solutions.
The protonation constants of some substituted 4-quinolone carboxylic acid anions (ofloxacin, pefloxacin and ciprofloxacin) were determined in lithium chloride solution of various concentrations at 293, 303 and 313 K using the pH-metric and spectrophotometric methods. The values of thermodynamic parameters (deltaG, deltaH and deltaS) for the first protonation step of these anions in 0.1M lithium chloride at 293 K, are reported. The formation of intramolecular hydrogen bonds is discussed.
Jelikic
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Faculty of Pharmacy, University of Beograd, P.O. Box 146, 11000 Beograd, Yugoslavia.
Veselinovic
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Djurdjevic
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