Water-Oil Partition Profiling of Ionized Drug Molecules Using Cyclic Voltammetry and a 96-Well Microfilter Plate System
Purpose. A new experimental set-up for studying partitioning of ionizable drugs at the interface between two immiscible electrolyte solutions (ITIES) by amperometry is presented. The method is quite general, as it can be applied to any charged drug molecule.
Methods. The procedure is based on 96-well microfilter plates with microporous filters to support 96 organic liquid membranes. The new methodology is first validated using a series of tetra-alkylammonium ions and subsequently used to construct the ion partition diagrams of 3,5-N,N-tetramethylaniline and 2,4-dinitrophenol. The lipophilicity of these drugs was examined by potentiometry and cyclic voltammetry in the NPOE/water system.
Results. Cyclic voltammetry resulted in potential-pH profiles of the studied drugs. When the aqueous phase pKa is already known, the logPNPOEof lipophilic drugs could be determined using a very little amount of solvents and drugs. The values of the partition coefficients for the neutral forms agree well with those obtained by potentiometry.
Conclusions. The procedure based on commercially available 96-well microfilter plates is shown to be useful for determining logP of ionized drugs in a rapid and efficient way.
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- 1.F. Reymond, G. Steyaert, P. A. Carrupt, B. Testa, and H. H. Girault. Ionic partition diagram: a potential-pH representation. J. Am. Chem. Soc. 118:11951-11957 (1996).Google Scholar
- 2.K. Arai. Electrochemical-behavior of drugs at immiscible oil-water interfaces. Bunseki Kugaku 451:41-53 (1996).Google Scholar
- 3.A. Avdeef, K. J. Box, J. E. A. Comer, C. Hibbert, and K. Y. Tam. pH-metric logP 10. Determination of liposomal membrane-water partition coefficients of ionizable drugs. Pharm. Res. 152:209-215 (1998).Google Scholar
- 4.D. A. Smith and H. van de Waterbeemd. Pharmacokinetics and metabolism in early drug discovery. Curr. Opin. Chem. Biol. 34:373-378 (1999).Google Scholar
- 5.A. Berthod, A. I. Allet, and M. Bully. Measurement of partition coefficients in waterless biphasic liquid systems by countercurrent chromatograpby. Anal. Chem. 683:431-436 (1996).Google Scholar
- 6.G. Caron, G. Steyaert, A. Pagliara, F. Reymond, P. Crivori, P. Gaillard, P. A. Carrupt, A. Avdeef, J. Comer, K. J. Box, H. H. Girault, and B. Testa. Structure-lipophilicity relationships of neutral and protonated #x0392-blockers Part I Intra-and intermolecular effects in isotropic solvent systems. Helv. Chim. Acta 828:1211-1222 (1999).Google Scholar
- 7.H. H. Girault. Charge transfer across liquid-liquid interfaces. Mod. Aspects Electrochem. 25:1-62 (1993).Google Scholar
- 8.F. Reymond, G. Steyaert, A. Pagliara, P. A. Carrupt, B. Testa, and H. H. Girault. Transfer Mechanism of Ionic Drugs: Piroxicam as a Agent Facilitating Proton Transfer. Helv. Chim. Acta 79:1651-1669 (1996).Google Scholar
- 9.F. Reymond, P. A. Carrupt, B. Testa, and H. H. Girault. Charge and delocalisation effects on the lipophilicity of protonable drugs. Chem. Eur. J. 51:39-47 (1999).Google Scholar
- 10.F. Reymond. Transfer mechanisms and lipophilicity of ionizable drugs. In Marcel Dekker (ed), Liquid Interfaces in Chemical, Biological, and Pharmaceutical Applications, New York, 2001, pp. 729-774.Google Scholar
- 11.M. Pourbaix. Atlas d'Equilibres Electrochimiques. Gautier-Villars, Paris, 1963.Google Scholar
- 12.M. H. Abraham, C. E. Green, and W. E. Acree. Correlation and prediction of the solubility of Buckminster-fullerene in organic solvents; estimation of some physicochemical properties. J. Chem. Soc.-Perkin Trans. 2:281-286 (2000).Google Scholar
- 13.A. Avdeef, J. E. A. Comer, and S. J. Thomson. Ph-Metric Log.3. Glass-electrode calibration in methanol water, applied to pK a determination of water-insoluble substances. Anal. Chem. 651:42-49 (1993).Google Scholar
- 14.K. Valko, C. M. Du, C. Bevan, D. P. Reynolds, and M. H. Abraham. Rapid method for the estimation of octanol/water partition coefficient (log P-oct) from gradient RP-HPLC retention and a hydrogen bond acidity term (Sigma alpha(H)(2)). Curr. Med. Chem. 89:1137-1146 (2001).Google Scholar
- 15.F. Wohnsland and B. Faller. High-throughput permeability pH profile and high-throughput alkane/water log P with artificial membranes. J. Med. Chem. 446:923-930 (2001).Google Scholar
- 16.V. Gobry, S. Ulmeanu, F. Reymond, G. Bouchard, P. A. Carrupt, B. Testa, and H. H. Girault. Generalization of ionic partition diagrams to lipophilic compounds and to biphasic systems with variable phase volume ratios. J. Am. Chem. Soc. 123:10684-10690 (2001).Google Scholar
- 17.Z. Samec, J. Langmaier, and A. Trojanek. Polarization phenomena at the water/O-Nitrophenyl octyl ether interface. 1. Evaluation of the standard Gibbs energies of ion transfer from the solubility and voltammetric measurements. J. Electroanal. Chem. 4091-2:1-7 (1996).Google Scholar
- 18.M. H. Abraham, C. M. Du, and J. A. Platts. Lipophilicity of the nitrophenols. J. Org. Chem. 6521:7114-7118 (2000).Google Scholar
- 19.V. Chopineaux-Courtois, F. Reymond, G. Bouchard, P. A. Carrupt, B. Testa, and H. H. Girault. Effects of charge and intermolecular structure on the lipophilicity of nitrophenols. J. Am. Chem. Soc. 121:1743-1747 (1999).Google Scholar
- 20.S. Wilke and T. Zerihun. Standard Gibbs energies of ion transfer across the water vertical bar 2-nitrophenyl octyl ether interface. J. Electroanal. Chem. 5151-2:52-60 (2001).Google Scholar
- 21.S. M. Ulmeanu, H. Jensen, Z. Samec, G. Bouchard, P. A. Carrupt, and H. H. Girault. Cyclic voltammetry of highly hydrophilic ions at a supported liquid membrane. J. Electroanal. Chem. 530:10-15 (2002).Google Scholar
- 22.G. Bouchard, P. A. Carrupt, B. Testa, V. Gobry, and H. H. Girault. Lipophilicity and solvation of anionic drugs. Chem. 815:3478-3484 (2002).Google Scholar
- 23.H. H. Girault and D. J. Schiffrin. Electrochemistry of liquid/liquid interfaces. Electroanal. Chem. 15:1-141 (1989).Google Scholar
- 24.H. Matsuda, Y. Yamada, K. Kanamori, Y. Kudo, and Y. Takeda. On the facilitation effect of neutral macrocyclic ligands on the ion transfer across the interface between aqueous and organic solutions.1. theoretical equation of ion-transfer-polarographic current-potential curves and its experimental-verification. Bull. Chem. Soc. Jpn. 645:1497-1508 (1991).Google Scholar
- 25.M. Senda, Y. Kubota, and H. Katano. Voltammetric Study of Drugs at Liquid-Liquid Interfaces. Marcel Dekker, New York, 2001.Google Scholar
- 26.T. Ohkouchi, T. Kakutani, and M. Senda. Electrochemical Study of the Transfer of Uncouplers across the Organic Aqueous Interface. Bioelectrochem. Bioenergetics 251:71-80 (1991).Google Scholar
- 27.T. B. Stolwijk, E. J. R. Sudholter, and D. N. Reinhoudt. Effect of crown ether lipophilicity on the facilitated transport of guanidinium thiocyanate through an immobilized liquid membrane. J. Am. Chem. Soc. 11116:6321-6329 (1989).Google Scholar