Capillary liquid chromatography as a tool for separation of hydrophobic basic drugs. Relation between tests for column characterization and real analysis

Kafková, Božena; Tesařová, Eva; Suchánková, Jana; Bosáková, Zuzana; Coufal, Pavel

doi:10.1002/jssc.200301383

Cited by 5 publications

(5 citation statements)

References 20 publications

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“…The hydrophobicity indices determined on TAG and Me-TAG were 0.44 and 2.75, respectively. The HI value for Me-TAG is comparable with that for LiChrosorb RP-select B (C-8) while other RPs (C-18) have HI usually about 4-5 [9]. These results confirmed the increase of stationary-phase hydrophobicity caused by methylation.…”

Section: Retention and The Hydrophobic Effectsupporting

confidence: 66%

Evaluation and comparison of a methylated teicoplanin aglycone to teicoplanin aglycone and natural teicoplanin chiral stationary phases

et al. 2006

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HPLC enantiomeric separations of a wide variety of racemic analytes was evaluated using chiral stationary phases (CSPs) based on the macrocyclic glycopeptides teicoplanin (T), teicoplanin aglycone (TAG), and methylated teicoplanin aglycone (Me-TAG) in two different mobile phase modes, i.e., the RP mode and the polar organic (PO) mode. Comparison of the enantiomeric separations using Chirobiotic T, Chirobiotic TAG, and the methylated form of TAG were conducted in order to gain a better understanding of the roles of the polar functional groups on the CSP. Substantial effects due to the cleavage of saccharides and/or methylation on chiral separations were observed in both separation modes. Improved separation efficiencies for many acidic analytes were obtained by methylating the H-bonding groups of TAG. These groups were believed to be a contributing factor to band broadening on TAG due to their negative effect on mass transfer between the stationary phase and mobile phase. Ionic/dipolar interactions between the carboxylate group of the analytes and the amine groups on T, TAG, or Me-TAG are important for chiral discrimination. Therefore, analytes possessing a carboxyl group are good candidates for successful separations on these CSPs. Hydrophobic interactions are important for enantiomeric separations in the RP mode where the H-bonding interactions between analytes and the chiral selectors are relatively weak. Me-TAG offers higher hydrophobicity, which can accentuate the interactions of analytes with hydrophobic moieties, but these interactions are not necessarily stereoselective. In the PO mobile phase, electrostatic/dipolar interactions between polar functional groups are the dominating interactions in chiral recognition. Another important factor is steric fit, which could be changed with every modification of the T structure. Therefore, substantial changes of enantioseparations were obtained within this studied group of CSPs. The PO mode was shown to be the most powerful mobile phase mode for enantiomeric separations on T-based stationary phases, mainly due to the improved efficiency. Methylation of the TAG proved to be a very useful tool for investigating the chiral recognition mechanism for this group of chiral selectors.

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Section: Retention and The Hydrophobic Effectsupporting

confidence: 66%

Evaluation and comparison of a methylated teicoplanin aglycone to teicoplanin aglycone and natural teicoplanin chiral stationary phases

et al. 2006

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“…Regarding the strongly hydrophobic nature and week basic properties of the studied 9-(alkylthio)acridines and based on the separation conditions for thioacridines pub- lished in the literature [3,[23][24][25], RP CLC realized on a LiChrosorb RP-select B capillary column was selected. The LiChrosorb RP-select B stationary phase is recommended for separation of hydrophobic alkaline compounds.…”

Section: Optimization Of Clc Separationmentioning

confidence: 99%

“…The LiChrosorb RP-select B stationary phase is recommended for separation of hydrophobic alkaline compounds. In contrast to the separation conditions published elsewhere [3,[23][24][25], the eluent was chosen to consist of methanol and water without any other eluent modifier to keep the eluent composition as simple as possible. The methanol content within the range of 100-85% v/v in the eluent for separation of the thioacridine derivatives on the LiChrosorb RP-select B capillary column was investigated.…”

Section: Optimization Of Clc Separationmentioning

confidence: 99%

“…In practical terms, the CLC method developed in this work shows shorter or similar analysis time and comparable sensitivity for structurally identical [26] and closely related [3,[23][24][25] thioacridines analyzed by CLC. The analysis time and sensitivity of the optimized MEKC method are similar to those observed in CZE [21,22] and reported in the literature for closely related compounds.…”

Section: Optimization Of Clc Separationmentioning

confidence: 99%

“…Infrared spectroscopy, electrochemistry, and NMR were utilized to get some principal physico-chemical properties of thioacridines related to their chemical structure [14][15][16]. For separation and quantification of acridine derivatives, HPLC [17][18][19][20], CZE [21,22], capillary LC (CLC) [3,[23][24][25] as well as GC and CLC with MS [26] were investigated. The highly hydrophobic properties of acridines make possible to use RP LC.…”

Section: Introductionmentioning

confidence: 99%

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Separation and quantification of 9‐(alkylthio)acridines by capillary micellar electrokinetic chromatography and capillary liquid chromatography

Nejmanová

Coufal²,

Bosáková

et al. 2007

J of Separation Science

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Various thioacridine derivatives are potential chemotherapeutics against various diseases which are intensively synthesized, characterized, and investigated by many research groups. Efficient, fast, and reliable separation and quantification methods for their analysis are still to be developed. MEKC and capillary LC (CLC) were applied for the separation and quantification of five highly hydrophobic, weakly basic, and structurally similar 9-(alkylthio)acridines. Since the common anionic and cationic surfactants failed to separate the strongly hydrophobic thioacridines by MEKC, sodium cholate was used in an alkaline BGE and successfully employed for their fast separation. In CLC, the weakly basic nature of the thioacridines necessitated use of LiChrosorb RP-select B sorbent as the stationary phase, which combined with a very simple mobile phase methanol/water yielded an efficient chromatographic separation system. Both, the MEKC and CLC optimized separation methods were then applied to quantify the thioacridines within a concentration range of 1.0 x 10(-5)-1.0 x 10(-3) mol/L and the obtained experimental results were critically compared. In practical terms, the MEKC analytical method can quantify the analytes much faster but with a lower reliability while the CLC method performs slower analysis with a higher repeatability of the experimental results.

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Determination of new pyridoquinoline derivatives and their quantification in urine by capillary liquid chromatography

Srbek

Coufal²,

Tesařová

et al. 2003

J of Separation Science

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Determination of new pyridoquinoline derivatives and their quantification in urine by capillary liquid chromatographyCapillary liquid chromatography (CLC) in reversed separation mode was applied to the quantification and impurity profile determination of eight newly synthesized pyridoquinolines. The CLC separation system consisted of Nucleosil C18 stationary phase and methanol containing 1% (v/v) of triethylamine (TEA) as the mobile phase. The optimized separation system enabled the separation of impurities from the main component and their quantification in a reasonable analysis time. The presence of TEA in the mobile phase greatly improved the peak shape and decreased the analysis time of the studied derivatives on the C18 stationary phase. Calibration curves of pyridoquinolines were plotted in a concentration range from 1.0610 -6 to 1.0610 -3 mol/L at two parallel detector wavelengths of 254 and 265 nm and subsequently used for quantification of pyridoquinoline derivatives in human urine. No pretreatment of the real biological sample was needed. Detection and quantification limits were calculated for all the derivatives and the detection limits of most of the pyridoquinolines were found to lie in the lmol/L concentration range. The proposed CLC separation system has proved to be a suitable method for quantification of test derivatives in samples containing human urine matrix.

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Capillary liquid chromatography as a tool for separation of hydrophobic basic drugs. Relation between tests for column characterization and real analysis

Cited by 5 publications

References 20 publications

Evaluation and comparison of a methylated teicoplanin aglycone to teicoplanin aglycone and natural teicoplanin chiral stationary phases

Evaluation and comparison of a methylated teicoplanin aglycone to teicoplanin aglycone and natural teicoplanin chiral stationary phases

Separation and quantification of 9‐(alkylthio)acridines by capillary micellar electrokinetic chromatography and capillary liquid chromatography

Determination of new pyridoquinoline derivatives and their quantification in urine by capillary liquid chromatography

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