Extreme Basicity of Biguanide Drugs in Aqueous Solutions: Ion Transfer Voltammetry and DFT Calculations

0463225 - ÚFCH JH 2017 RIV US eng J - Článek v odborném periodiku
Langmaier, Jan - Pižl, Martin - Samec, Zdeněk - Záliš, Stanislav
Extreme Basicity of Biguanide Drugs in Aqueous Solutions: Ion Transfer Voltammetry and DFT Calculations.
Journal of Physical Chemistry A. Roč. 120, č. 37 (2016), s. 7344-7350. ISSN 1089-5639. E-ISSN 1520-5215
Grant CEP: GA ČR(CZ) GA15-03139S
Institucionální podpora: RVO:61388955
Klíčová slova: voltammetry * Alkalinity * Complexation
Kód oboru RIV: CG - Elektrochemie
Impakt faktor: 2.847, rok: 2016

Ion transfer voltammetry is used to estimate the acid dissociation constants Ka1 and Ka2 of the mono- and diprotonated forms of the biguanide drugs metformin (MF), phenformin (PF), and 1-phenylbiguanide (PB) in an aqueous solution. Measurements gave the pKa1 values for MFH+, PFH+, and PBH+ characterizing the basicity of MF, PF, and PB, which are significantly higher than those reported in the literature. As a result, the monoprotonated forms of these biguanides should prevail in a considerably broader range of pH 1–15 (MFH+, PFH+) and 2–13 (PBH+). DFT calculations with solvent correction were performed for possible tautomeric forms of neutral, monoprotonated, and diprotonated species. Extreme basicity of all drugs is confirmed by DFT calculations of pKa1 for the most stable tautomers of the neutral and protonated forms with explicit water molecules in the first solvation sphere included.
Trvalý link: http://hdl.handle.net/11104/0262469