Correlation of Octanol-Water Partition Coefficients with Capacity Factors Measured by Micellar Electrokinetic Chromatography.

Ishihama, Yasushi; Oda, Yoshiya; Uchikawa, Kiyohiko; Asakawa, Naoki

doi:10.1248/cpb.42.1525

Cited by 50 publications

(23 citation statements)

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“…However, the traditional shake-flask method for determination of partition coefficients is time consuming, laborious, and requires relatively large amounts of pure and stable compounds. Thus, several indirect methods for determination of octanol-water partition have been used, e.g., reversed-phase HPLC [5][6][7][8][9][10][11], MEKC [12][13][14][15][16][17][18][19][20][21][22][23], and microemulsion electrokinetic chromatography (MEEKC) [21,[24][25][26] allowing linear free energy relationships between retention factors, k, and the partition coefficient, P, to be established.…”

Section: Introductionmentioning

confidence: 99%

Determination of octanol‐water partition coefficients for carbonate esters and other small organic molecules by microemulsion electrokinetic chromatography

et al. 2003

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Microemulsion electrokinetic chromatography (MEEKC) was assessed as a tool for determination of octanol-water partition coefficients using 34 solutes encompassing 8 carbonate esters. It was confirmed that microemulsions containing 1.44-2.88% w/w SDS, 6.49% w/w 1-butanol, and 0.82% w/w n-heptane constitute a good model of octanol-water partitioning in the pH range of 1.4-7.4. Use of the migration index concept led to improved repeatability of the MEEKC method compared to the use of retention factors. Using a dynamical coating, a high electroosmotic flow at pH 1.4 and 4.75 was achieved expanding the practical pH working range of the MEEKC system. The correlation obtained between the migration index and log P was unaffected by pH indicating that the properties of the microemulsion droplets and, thus, partitioning are independent of pH. No evidence for congeneric behavior was found for the sample set comprising solutes with different hydrogen bonding properties suggesting that simple reference compounds can be used as calibrators. Lipophilicity estimates for the series of carbonate esters were obtained. The increase in lipophilicity with chain length was smaller than expected from the Hansch substituent constant, pi.

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Section: Introductionmentioning

confidence: 99%

Determination of octanol‐water partition coefficients for carbonate esters and other small organic molecules by microemulsion electrokinetic chromatography

et al. 2003

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“…Thus, the capacity factors were transformed into the partition coefficients between water and octanol. This was carried out by calibrating log k to the log P OW scale in the particular systems by the use of measured log k of reference substances with known P OW [26,30,[33][34][35][36]. We name the values for the analytes derived by calibration log P, in contrast to log P OW , the literature values, the data directly measured after partitioning between water and octanol (see Section 2), and those obtained from calculation by the computer program.…”

Section: Capacity Factor and Log P Owmentioning

confidence: 99%

“…3). Data for log P OW are taken from [26,[33][34][35][36]. r, linear correlation coefficient for log k i vs. log P OW .…”

Section: Capacity Factor and Log P Owmentioning

confidence: 99%

Comparison of the retention characteristics of different pseudostationary phases for microemulsion and micellar electrokinetic chromatography of betamethasone and derivatives

Lucangioli¹,

Carducci²,

Scioscia³

et al. 2003

Electrophoresis

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Five electrokinetic chromatography systems were compared concerning retention behavior and lipophilicity. Comparison was based on capacity (retention) factors of some steroidal drugs, and on log P(OW) values derived by the aid of reference substances. In all systems the aqueous buffer consisted of phosphate (20 mM, pH 7.5). Two systems had micelles, three systems microdroplets as negatively charged pseudostationary phases. The micelles were formed by sodium dodecyl sulfate (SDS) and sodium cholate, respectively. One microemulsion consisted (as usual) from octane as oil, butanol as cosurfactant and SDS as charged tenside. Two microemulsions were made from biosurfactants (phosphatidylcholine, isopropylmyristate) to better simulate biopartitioning of the drugs. Even for noncharged analytes a change in migration sequence and thus in log P(OW) was observed for the systems consisting of the biosurfactants, compared to the others. For the former systems, log P(OW) derived from the capacity factors agree for all analytes with those obtained from calculation by computer software based on the structure of the drugs, and with experimental data directly obtained from octanol/water partitioning.

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“…The more negative DG8 is, the more the equilibrium is moved to the micelle side (strong interaction with the micelles). Depending on the chemical structure of the drugs and the vehicles, various chemical interactions additional to hydrophobic interactions, such as dipole interaction and hydrogen bonding, may occur between them in the partitioning process [14][15][16]22,37]. For the micellar systems where hydrophobic interactions play an important role in influencing the migration and selectivity of drugs, one may expect a linear relationship between the logarithm of the capacity factor, the partition coefficient and the logarithm of the n-octanol/water partition coefficient.…”

Section: Interactions Between Drugs and Micellesmentioning

confidence: 99%

“…Furthermore, electrostatic interaction and hydrogen bonding effects between solutes and surfactant were observed (14). The characterization of the hydrophobicity/ hydrophilicity of solutes in micelles was evaluated by electrokinetic chromatography (EKC) [15,16]. Microemulsion electrokinetic chromatography [MEEKC] was investigated by Watarai [17].…”

Section: Introductionmentioning

confidence: 99%

Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically

Neubert¹,

Mrestani²

2001

Biopharm & Drug Disp

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This review offers a detailed discussion of the interaction between pharmaceutical compounds and vehicles using the affinity capillary electrophoresis and the microemulsion electrokinetic chromatography. Partition coefficients of drugs were calculated between a micelle and an aqueous phases from the measurement of the migration time, provided the critical micelle concentration and the phase ratio are known. Thermodynamic quantities such as enthalpy and entropy changes of micellar solubilization were calculated from the temperature dependence of the partition coefficients. Partial specific volumes were measured using dynamic light scattering. The logarithm of the partition coefficients and the capacity factor in the micellar system were correlated with the logarithm of the n-octanol/water partition coefficients.

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Correlation of Octanol-Water Partition Coefficients with Capacity Factors Measured by Micellar Electrokinetic Chromatography.

Cited by 50 publications

References 0 publications

Determination of octanol‐water partition coefficients for carbonate esters and other small organic molecules by microemulsion electrokinetic chromatography

Determination of octanol‐water partition coefficients for carbonate esters and other small organic molecules by microemulsion electrokinetic chromatography

Comparison of the retention characteristics of different pseudostationary phases for microemulsion and micellar electrokinetic chromatography of betamethasone and derivatives

Use of affinity capillary electrophoresis for characterizing pharmaceutical colloidal vehicle systems thermodynamically

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