Feasibility of the estimation of octanol-water distribution coefficients of acidic drugs by microemulsion electrokinetic chromatography
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 evalua...
| Autores: | , , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | España |
| Recursos: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/161986 |
| Acesso em linha: | https://hdl.handle.net/2445/161986 |
| Access Level: | acceso abierto |
| Palavra-chave: | Electroforesi capil·lar Lipofília Capillary electrophoresis Lipophilicity |
| Resumo: | 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 |
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