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ADMET and DMPK, Vol. 6 No. 1, 2018.

Short communication, Note

https://doi.org/10.5599/admet.6.1.510

Feasibility of the estimation of octanol-water distribution coefficients of acidic drugs by microemulsion electrokinetic chromatography

Alejandro Fernández-Pumarega ; Departament de Química Analítica and Institute of Biomedicine of the University of Barcelona (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain
Susana Amézqueta orcid id orcid.org/0000-0001-8976-467X ; Departament de Química Analítica and Institute of Biomedicine of the University of Barcelona (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain
Elisabet Fuguet ; Departament de Química Analítica and Institute of Biomedicine of the University of Barcelona (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain
Marti Rosés ; Departament de Química Analítica and Institute of Biomedicine of the University of Barcelona (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain

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Abstract

Previous studies have shown that a microemulsion electrokinetic chromatography (MEEKC) system can estimate the logarithm of the octanol-water partition coefficient (log Po/w) of neutral solutes. In the present work, the applicability of the method to partially and fully ionized acids has been evaluated. Naproxen, a monoprotic acid, has been used as test solute. The retention factor (k) of this compound has been measured in MEEKC at several values of pH and the retention factor-pH profile has been established. As log Po/w correlates with log kMEEKC for neutral compounds, this correlation has been used to estimate the logarithm of the octanol-water partition coefficient of the neutral (log Po/w(HA)), and the fully ionized (log P o/w(A-)) forms of naproxen. Then, the logarithm of the octanol-water distribution coefficient (log Do/w) of the partially ionized form of the acid has been estimated. The comparison of the estimated values with the ones obtained experimentally using the classical procedures, such as the shake-flask method, shows differences under 0.4 log Do/w units either if the acid is partially ionized or in its neutral form in the most part of the pH range. However, the method overestimates the log Do/w of the highly (>99.5 %) or fully ionized form of naproxen.

Keywords

Capillary electrophoresis; MEEKC; log Do/w; lipophilicity

Hrčak ID:

196401

URI

https://hrcak.srce.hr/196401

Publication date:

25.3.2018.

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