Determination of thermodynamic pKa values of pharmaceuticals from five different groups using capillary electrophoresis. Issue 7 (2nd March 2015)

• Record Type: Journal Article
• Authors: Zrnčić, Mirta; Babić, Sandra; Mutavdžić Pavlović, Dragana
• Is Part Of: Journal of separation science. Volume 38:Issue 7(2015:Apr.)
• Page Start: 1232
• Page End: 1239
• Publication Date: 2015-03-02
• Subjects: Separation (Technology) -- Periodicals; Chromatographic analysis -- Periodicals; 543.089
• DOI: 10.1002/jssc.201401057
• Languages: English
• ISSNs: 1615-9306

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>A determination of the thermodynamic acid dissociation constants (p<italic>K</italic>_a) of 22 frequently used pharmaceuticals using capillary electrophoresis in aqueous media is presented in this work. The investigated pharmaceuticals belong to different pharmacological groups: macrolides, fluoroquinolones, sulfonamides, β‐lactams, tetracyclines, and other miscellaneous pharmaceuticals. The electrophoretic mobilities of the investigated analytes were monitored in a pH range from 2.00 to 10.82. The data were fitted with an appropriate mathematical model using a nonlinear regression analysis to obtain p<italic>K</italic>_a values. Experimentally obtained data were well described by the mathematical model chosen for each analyte that was confirmed by <italic>r</italic>² values higher than 0.99 for most of the investigated analytes. Extrapolations to zero ionic strength were used to determine the thermodynamic p<italic>K</italic>_a values. Experimentally obtained acid dissociation constants were interpreted using structural formulae of investigated analytes and the moieties corresponding to specific p<italic>K</italic>_a were identified.</p> </abstract>