Hydrodynamic voltammetry at the liquid-liquid interface: Application to the transfer of ionised drug molecules

Matěj Velický, Kin Y. Tam, Robert A W Dryfe*

*Corresponding author for this work

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Liquid/liquid electrochemistry has been used to study the transfer of weakly ionised species across the interface between water and 1,2-dichloroethane. It is shown that while transfer of a fully ionised species can be readily used for determination of its diffusion coefficient, transfer of a partially ionised species, such as many common pharmaceutical agents, involves complex ionisation/distribution behaviour, which invalidates the conventional analysis. As a result, the aqueous diffusion coefficient of the transferred species is underestimated by at least one order of magnitude. An alternative method to study the transfer of partially ionised drug molecules employing a rotating liquid/liquid interface is proposed and reported. The alternative approach, which is based on a previously reported rotating diffusion cell approach, employs a lipophilic membrane that stabilises the liquid/liquid interface and allows stirring. This hydrodynamically controlled configuration was successfully applied to transfer of partially ionised drug species, and expected values of the aqueous diffusion coefficient were obtained.

Original languageEnglish
Pages (from-to)94-102
Number of pages9
JournalJournal of Electroanalytical Chemistry
Volume683
DOIs
Publication statusPublished - 01 Sep 2012
Externally publishedYes

Fingerprint

Voltammetry
Hydrodynamics
Molecules
Liquids
Pharmaceutical Preparations
Electrochemistry
Drug products
Ionization
Membranes
Water

Keywords

  • Diffusion
  • Hydrodynamic voltammetry
  • Ion transfer
  • Liquid/liquid electrochemistry
  • Membrane
  • Rotating interface

Cite this

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abstract = "Liquid/liquid electrochemistry has been used to study the transfer of weakly ionised species across the interface between water and 1,2-dichloroethane. It is shown that while transfer of a fully ionised species can be readily used for determination of its diffusion coefficient, transfer of a partially ionised species, such as many common pharmaceutical agents, involves complex ionisation/distribution behaviour, which invalidates the conventional analysis. As a result, the aqueous diffusion coefficient of the transferred species is underestimated by at least one order of magnitude. An alternative method to study the transfer of partially ionised drug molecules employing a rotating liquid/liquid interface is proposed and reported. The alternative approach, which is based on a previously reported rotating diffusion cell approach, employs a lipophilic membrane that stabilises the liquid/liquid interface and allows stirring. This hydrodynamically controlled configuration was successfully applied to transfer of partially ionised drug species, and expected values of the aqueous diffusion coefficient were obtained.",
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Hydrodynamic voltammetry at the liquid-liquid interface : Application to the transfer of ionised drug molecules. / Velický, Matěj; Tam, Kin Y.; Dryfe, Robert A W.

In: Journal of Electroanalytical Chemistry, Vol. 683, 01.09.2012, p. 94-102.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Hydrodynamic voltammetry at the liquid-liquid interface

T2 - Application to the transfer of ionised drug molecules

AU - Velický, Matěj

AU - Tam, Kin Y.

AU - Dryfe, Robert A W

PY - 2012/9/1

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N2 - Liquid/liquid electrochemistry has been used to study the transfer of weakly ionised species across the interface between water and 1,2-dichloroethane. It is shown that while transfer of a fully ionised species can be readily used for determination of its diffusion coefficient, transfer of a partially ionised species, such as many common pharmaceutical agents, involves complex ionisation/distribution behaviour, which invalidates the conventional analysis. As a result, the aqueous diffusion coefficient of the transferred species is underestimated by at least one order of magnitude. An alternative method to study the transfer of partially ionised drug molecules employing a rotating liquid/liquid interface is proposed and reported. The alternative approach, which is based on a previously reported rotating diffusion cell approach, employs a lipophilic membrane that stabilises the liquid/liquid interface and allows stirring. This hydrodynamically controlled configuration was successfully applied to transfer of partially ionised drug species, and expected values of the aqueous diffusion coefficient were obtained.

AB - Liquid/liquid electrochemistry has been used to study the transfer of weakly ionised species across the interface between water and 1,2-dichloroethane. It is shown that while transfer of a fully ionised species can be readily used for determination of its diffusion coefficient, transfer of a partially ionised species, such as many common pharmaceutical agents, involves complex ionisation/distribution behaviour, which invalidates the conventional analysis. As a result, the aqueous diffusion coefficient of the transferred species is underestimated by at least one order of magnitude. An alternative method to study the transfer of partially ionised drug molecules employing a rotating liquid/liquid interface is proposed and reported. The alternative approach, which is based on a previously reported rotating diffusion cell approach, employs a lipophilic membrane that stabilises the liquid/liquid interface and allows stirring. This hydrodynamically controlled configuration was successfully applied to transfer of partially ionised drug species, and expected values of the aqueous diffusion coefficient were obtained.

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KW - Hydrodynamic voltammetry

KW - Ion transfer

KW - Liquid/liquid electrochemistry

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