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The behavior of seven hydroxy anthraquinone derivatives was studied by capillary zone electrophoresis and micellar electrokinetic chromatography. The effects of buffer pH (6.5-10.8) and sodium dodecyl sulfate concentration (10-20 mmol L-1) on the effective mobilities of the analytes and their separation were tested. A comparison of the two optimized separation systems showed that micellar electrokinetic chromatography was superior as it permits separation of all the seven analytes within 15 min, using 15 mmol L-1 sodium dodecyl sulfate in 10 mmol L-1 tetraborate buffer, pH 8.5, at a voltage of 20 kV. The calibration curves were linear in the concentration range from 5.0 · 10-7 to 5.0 · 10-4 mol L-1 for most of the analytes, at a detection wavelength of 254 nm. LOD and LOQ values of the analytes were in the ranges of 2.10 · 10-7-1.28 · 10-6 mol L-1and 6.99 · 10-7-4.25 · 10-6 mol L-1, respectively. The proposed separation conditions were applied to determination of 1,2-dihydroxy anthraquinone (alizarin) and 1,2,4-trihydroxy anthraquinone (purpurin) in Rubia tinctorum aglycone and of the recently described 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone and 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone in the mycelium of fungi Geosmithia lavendula. [ABSTRACT FROM AUTHOR]

Abstract: Fatal drug overdoses are a cause for concern all over the world. We present here a lipid-based formulation which has a strong affinity for some common illicit street drugs and can be used in vivo as a lipid ‘sink’. In this study, the in vitro interactions of nine lipophilic drugs and three lipid dispersions were determined by electrokinetic capillary chromatography and fluorescence polarization. Two lipid dispersions, zwitterionic 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine (POPC) and an anionic mixture of POPC and 1-palmitoyl-2-oleyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (POPG) were tested and compared with a commercial lipid dispersion Intralipid®, which has been successfully used for resuscitation of patients in cases of anesthetic overdoses. The interactions between dispersions and the drugs were quantified by means of retention factors and distribution constants, which makes the results highly comparable to those obtained from any other formulation of lipids. The results demonstrate a stronger interaction between the drugs and an artificial liposome dispersion than with the commercial Intralipid dispersion. The liposome dispersion composed of POPC and POPG functions as a lipid ‘sink’ for efficient entrapment of various lipophilic drugs. [ABSTRACT FROM AUTHOR]

Interactions between Intralipid dispersion and local anesthetics (bupivacaine, prilocaine, and lidocaine) were investigated. The amount of bupivacaine (the most cardiotoxic analyte of the local anesthetics studied) entrapped in Intralipid in the presence of plasma was studied using an off-line filtration and solid phase extraction method combined with capillary zone electrophoresis for quantification of free unbound bupivacaine. To confirm interactions between the analytes and Intralipid at lower concentrations, direct injection mass spectrometry was used. The use of immobilized Intralipid chromatography-atmospheric pressure ionization–ion trap mass spectrometry in the study of interactions between drugs and Intralipid dispersion is demonstrated. Finally, interactions between Intralipid dispersion and local anesthetics were investigated by electrokinetic capillary chromatography. The electrophoretic mobility of the Intralipid dispersed phase was calculated using the iterative procedure and a homologous series of alkyl phenyl benzoates (C1–C6), and the retention factors for the analytes were determined. [ABSTRACT FROM AUTHOR]

Abstract: Teicoplanin (T) is a macrocyclic glycopeptide that is highly effective as a chiral selector for enantiomeric separations. In this study, we used three teicoplanin-based chiral stationary phases (CSPs) – native teicoplanin, teicoplanin aglycon (TAG) and recently synthesized methylated teicoplanin aglycon (MTAG). In order to examine the importance of various interaction types in the chiral recognition mechanism the three related CSPs were evaluated and compared using a linear free energy relationship (LFER). The capacity factors of 19 widely different solutes, with known solvation parameters, were determined on each of the columns under the same mobile phase conditions used for the chiral separations. The regression coefficients obtained revealed the magnitude of the contribution of individual interaction types to the retention on the compared columns under those specific experimental conditions. Statistically derived standardized regression coefficients were used to evaluate the contribution of individual molecular interactions within one stationary phase. It has been concluded that intermolecular interactions of the hydrophobic type significantly contribute to retention on all the CSPs studied here. Other retention increasing factors are n- and π-electron interactions and dipole–dipole or dipole-induced dipole ones, while hydrogen donating or accepting interactions are more predominant with the mobile phase than with the stationary phases. However, these types of interactions are not equally significant for all the CSPs studied. [Copyright &y& Elsevier]