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Ma Y, Chen X, Javeria H, Du Z. High-throughput screening of LogD by using a sample pooling approach based on the traditional shake flask method. J Chromatogr B Analyt Technol Biomed Life Sci 2023; 1227:123804. [PMID: 37393793 DOI: 10.1016/j.jchromb.2023.123804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/30/2023] [Accepted: 06/15/2023] [Indexed: 07/04/2023]
Abstract
A new approach for screening LogD is presented. The method is based on the shake flask method combined with rapid generic LC-MS/MS bioanalysis by using a sample pooling approach that enables high-throughput screening of LogD or LogP in the drug discovery stage. The method is evaluated by a comparison of measured LogD between single and pooled compounds for a test set of structurally diverse compounds with a wide range of LogD values (from -0.04 to 6.01). Test compounds include 10 commercially available drug standards along with 27 new chemical entities. A good correlation (RMSE = 0.21, R2 = 0.9879) of LogD between the single and pooled compounds was obtained, suggesting that at least 37 compounds can be simultaneously measured with acceptable accuracy. The sample pooling method significantly reduced the number of bioanalysis samples as compared to the single compound measurement by the conventional shake flask method. The impact of DMSO content on LogD measurement was also investigated and the result demonstrated that at least 0.5% DMSO was tolerated in this method. The current new development will facilitate the drug discovery process by more rapidly assessing the LogD or LogP of drug candidates.
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Affiliation(s)
- Yongfen Ma
- College of Chemistry, Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiaowei Chen
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 117004, Liaoning, China
| | - Huma Javeria
- College of Chemistry, Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029, China
| | - Zhenxia Du
- College of Chemistry, Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029, China.
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Miyabe K, Inaba S, Umeda M. A study on attempt for determination of permeation kinetics of coumarin at lipid bilayer of liposomes by using capillary electrophoresis with moment analysis theory. J Chromatogr A 2023; 1687:463691. [PMID: 36542884 DOI: 10.1016/j.chroma.2022.463691] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 11/14/2022] [Accepted: 11/28/2022] [Indexed: 11/30/2022]
Abstract
It was tried to develop a moment analysis method for the determination of lipid membrane permeability. The first absolute and second central moments of elution peaks measured by liposome electrokinetic chromatography (LEKC) are analyzed by using moment equations. As a concrete example, elution peak profiles of coumarin in a LEKC system, in which liposomes consisting of 1-palmitoyl-2-oleoyl-sn‑glycero-3-phosphocholine (POPC) and phosphatidylserine (PS) are used as a pseudo-stationary phase, were analyzed. It seems that lipid membrane permeability of coumarin across the lipid bilayer of POPC/PS liposomes was measured by the moment analysis method because previous permeability measurements using parallel artificial membrane permeability assay (PAMPA) and Caco-2 cells indicated that coumarin is permeable across lipid bilayer. However, it was also pointed out that the moment analysis method with LEKC is not effective for the determination of lipid membrane permeability and that it provides information about adsorption/desorption kinetics at lipid bilayer of liposomes. Therefore, different moment equations were also developed for the determination of adsorption/desorption rate constants of coumarin from the LEKC data. It was demonstrated that permeation rate constants at lipid bilayer or adsorption/desorption rate constants can be determined from the LEKC data on the basis of moment analysis theory for the mass transfer phenomena of coumarin at the lipid bilayer of POPC/PS liposomes. Mass transfer kinetics of solutes at lipid bilayer should be determined under the conditions that liposomes originally be because they are self-assembling and dynamic systems formed through weak interactions between phospholipid monomers. The moment analysis method using LEKC is effective for the experimental determination of the mass transfer rate constants at the lipid bilayer of liposomes because neither immobilization nor chemical modification of liposomes is necessary when LEKC data are measured. It is expected that the results of this study contribute to the dissemination of an opportunity for the determination of permeation rate constants or adsorption/desorption rate constants at the lipid bilayer of liposomes to many researchers because capillary electrophoresis is widespread.
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Affiliation(s)
- Kanji Miyabe
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshimaku, Tokyo 171-8501, Japan.
| | - Shunta Inaba
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshimaku, Tokyo 171-8501, Japan
| | - Momoko Umeda
- Department of Chemistry, Faculty of Science, Rikkyo University, 3-34-1, Nishi-Ikebukuro, Toshimaku, Tokyo 171-8501, Japan
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Jiang H, Zhang H, Yin SJ, Lu M, Wang X, Yang FQ. Determination of lipid-water partition coefficient of neutral and ionic drugs by liposome electrokinetic chromatography. Electrophoresis 2021; 42:1436-1449. [PMID: 33908064 DOI: 10.1002/elps.202000382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 11/08/2022]
Abstract
Profiling of lipid-water partition coefficients (KL/W ) of drugs is an essential issue during the early stage of drug development. In this study, two liposomes, including 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) + cholesterol (Chol) (DSPC/Chol liposomes) and soybean lecithin (SPC) + Chol (SPC/Chol liposomes), were prepared for the liposome electrokinetic chromatography (LEKC) analysis, and the logarithm of lipid-water partition coefficients (log KL/W ) of neutral and ionic drugs were determined based on an iterative method. The log KL/W values determined by the SPC/Chol or DSPC/Chol liposomes LEKC were linearly fitted, which showed a good fitting coefficient (R2 = 0.89). Furthermore, the linear relationship between the data obtained from LEKC system and octanol-water system, immobilized artificial membrane, Caco-2 cell model, and software prediction was analyzed, respectively. Results illustrated that DSPC/Chol liposomes or SPC/Chol liposomes had a good linear relationship with Caco-2 cell model, and R2 was 0.81 and 0.72, respectively. Moreover, the linear free energy relationship analysis suggested that the solute volume, hydrogen bond basicity, and J- were the main descriptors that drove the partition process of solutes in the SPC/Chol or DSPC/Chol LEKC system. In addition, the normalized properties of the SPC/Chol and DSPC/Chol LEKC systems through linear free energy relationship analysis were very close. In short, DSPC/Chol liposomes are more suitable for simulating cell membranes than SPC/Chol liposomes, and the developed LEKC is an effective partitioning model for measuring the log KL/W of drugs.
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Affiliation(s)
- Hui Jiang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | - Hao Zhang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | - Shi-Jun Yin
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | - Min Lu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | - Xu Wang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | - Feng-Qing Yang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
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Godyń J, Gucwa D, Kobrlova T, Novak M, Soukup O, Malawska B, Bajda M. Novel application of capillary electrophoresis with a liposome coated capillary for prediction of blood-brain barrier permeability. Talanta 2020; 217:121023. [DOI: 10.1016/j.talanta.2020.121023] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 12/20/2022]
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Gao Q, Liu H, Ding Q, Du J, Liu C, Yang W, Shen P, Yang C. A red-emitting indolium fluorescence probe for membranes - flavonoids interactions. LUMINESCENCE 2018; 33:582-587. [PMID: 29405584 DOI: 10.1002/bio.3449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/03/2017] [Indexed: 12/12/2022]
Abstract
The red-emitting indolium derivative compound (E)-2-(4-(diphenylamino)styryl)-1,3,3-trimethyl-3H-indol-1-ium iodide (H3) was demonstrated as a sensitive membrane fluorescence probe. The probe located at the interface of liposomes when mixed showed much fluorescence enhancement by inhibiting the twisted intramolecular charge transfer state. After ultrasonic treatment, it penetrated into lipid bilayers with the emissions leveling off and a rather large encapsulation efficiency (71.4%) in liposomes. The ζ-potential and particle size measurement confirmed that the charged indolium group was embedded deeply into lipid bilayers. The probe was then used to monitor the affinities of antioxidant flavonoids for membranes. It was verified that quercetin easily interacted with liposomes and dissociated the probe from the internal lipid within 60 s under the condition of simply mixing. The assessment of binding affinities of six flavonoids and the coincident results with their antioxidation activities indicated that it was a promising membrane probe for the study of drug bio-affinities.
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Affiliation(s)
- Qingyun Gao
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Han Liu
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Qiongjie Ding
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Jinya Du
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Chunlin Liu
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Wei Yang
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Ping Shen
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
| | - Changying Yang
- College of Biological and Pharmaceutical Science, China Three Gorges University, Yichang, P. R. China
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Hunckler MD, Tilley JMR, Roeder RK. Molecular transport in collagenous tissues measured by gel electrophoresis. J Biomech 2015; 48:4087-4092. [PMID: 26482732 DOI: 10.1016/j.jbiomech.2015.10.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 09/29/2015] [Accepted: 10/04/2015] [Indexed: 10/22/2022]
Abstract
Molecular transport in tissues is important for drug delivery, nutrient supply, waste removal, cell signaling, and detecting tissue degeneration. Therefore, the objective of this study was to investigate gel electrophoresis as a simple method to measure molecular transport in collagenous tissues. The electrophoretic mobility of charged molecules in tissue samples was measured from relative differences in the velocity of a cationic dye passing through an agarose gel in the absence and presence of a tissue section embedded within the gel. Differences in electrophoretic mobility were measured for the transport of a molecule through different tissues and tissue anisotropy, or the transport of different sized molecules through the same tissue. Tissue samples included tendon and fibrocartilage from the proximal (tensile) and distal (compressive) regions of the bovine flexor tendon, respectively, and bovine articular cartilage. The measured electrophoretic mobility was greatest in the compressive region of the tendon (fibrocartilage), followed by the tensile region of tendon, and lowest in articular cartilage, reflecting differences in the composition and organization of the tissues. The anisotropy of tendon was measured by greater electrophoretic mobility parallel compared with perpendicular to the predominate collagen fiber orientation. Electrophoretic mobility also decreased with increased molecular size, as expected. Therefore, the results of this study suggest that gel electrophoresis may be a useful method to measure differences in molecular transport within various tissues, including the effects of tissue type, tissue anisotropy, and molecular size.
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Affiliation(s)
- Michael D Hunckler
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Jennifer M R Tilley
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Ryan K Roeder
- Department of Aerospace and Mechanical Engineering, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, IN 46556, USA.
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Pyranoxanthones: Synthesis, growth inhibitory activity on human tumor cell lines and determination of their lipophilicity in two membrane models. Eur J Med Chem 2013; 69:798-816. [DOI: 10.1016/j.ejmech.2013.09.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 01/05/2023]
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9
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Franzen U, Østergaard J. Physico-chemical characterization of liposomes and drug substance–liposome interactions in pharmaceutics using capillary electrophoresis and electrokinetic chromatography. J Chromatogr A 2012; 1267:32-44. [DOI: 10.1016/j.chroma.2012.07.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Revised: 07/02/2012] [Accepted: 07/06/2012] [Indexed: 01/19/2023]
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Liu X, Testa B, Fahr A. Lipophilicity and its relationship with passive drug permeation. Pharm Res 2010; 28:962-77. [PMID: 21052797 DOI: 10.1007/s11095-010-0303-7] [Citation(s) in RCA: 270] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 10/11/2010] [Indexed: 12/18/2022]
Abstract
In this review, we first summarize the structure and properties of biological membranes and the routes of passive drug transfer through physiological barriers. Lipophilicity is then introduced in terms of the intermolecular interactions it encodes. Finally, lipophilicity indices from isotropic solvent systems and from anisotropic membrane-like systems are discussed for their capacity to predict passive drug permeation across biological membranes such as the intestinal epithelium, the blood-brain barrier (BBB) or the skin. The broad evidence presented here shows that beyond the predictive power of lipophilicity parameters, the various intermolecular forces they encode allow a mechanistic interpretation of passive drug permeation.
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Affiliation(s)
- Xiangli Liu
- Department of Pharmaceutical Technology, Friedrich-Schiller-Universität Jena, Lessingstrasse 8, 07743 Jena, Germany.
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11
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Henchoz Y, Romand S, Schappler J, Rudaz S, Veuthey JL, Carrupt PA. High-throughput log P determination by MEEKC coupled with UV and MS detections. Electrophoresis 2010; 31:952-64. [DOI: 10.1002/elps.200900540] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Østergaard J, Moeller EH. Ghrelin-liposome interactions: Characterization of liposomal formulations of an acylated 28-amino acid peptide using CE. Electrophoresis 2010; 31:339-45. [DOI: 10.1002/elps.200900394] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Franzen U, Jorgensen L, Larsen C, Heegaard NHH, Østergaard J. Determination of liposome-buffer distribution coefficients of charged drugs by capillary electrophoresis frontal analysis. Electrophoresis 2009; 30:2711-9. [DOI: 10.1002/elps.200900013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Wan H, Åhman M, Holmén AG. Relationship between Brain Tissue Partitioning and Microemulsion Retention Factors of CNS Drugs. J Med Chem 2009; 52:1693-700. [DOI: 10.1021/jm801441s] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hong Wan
- Lead Generation, DMPK and Physical Chemistry, AstraZeneca R&D Mölndal, SE-431 83 Mölndal, Sweden
| | - Madeleine Åhman
- Lead Generation, DMPK and Physical Chemistry, AstraZeneca R&D Mölndal, SE-431 83 Mölndal, Sweden
| | - Anders G. Holmén
- Lead Generation, DMPK and Physical Chemistry, AstraZeneca R&D Mölndal, SE-431 83 Mölndal, Sweden
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Henchoz Y, Bard B, Guillarme D, Carrupt PA, Veuthey JL, Martel S. Analytical tools for the physicochemical profiling of drug candidates to predict absorption/distribution. Anal Bioanal Chem 2009; 394:707-29. [DOI: 10.1007/s00216-009-2634-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 01/16/2009] [Accepted: 01/19/2009] [Indexed: 10/21/2022]
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Østergaard J, Jorgensen L, Engelbrecht Thomsen A, Weng Larsen S, Larsen C, Jensen H. Drug-liposome distribution phenomena studied by capillary electrophoresis-frontal analysis. Electrophoresis 2008; 29:3320-4. [DOI: 10.1002/elps.200700757] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Boija E, Lundquist A, Nilsson M, Edwards K, Isaksson R, Johansson G. Bilayer disk capillary electrophoresis: A novel method to study drug partitioning into membranes. Electrophoresis 2008; 29:3377-83. [DOI: 10.1002/elps.200700682] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Martel S, Guillarme D, Henchoz Y, Galland A, Veuthey J, Rudaz S, Carrupt P. Chromatographic Approaches for Measuring Log
P. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/9783527621286.ch13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Benilova I, Chegel VI, Ushenin YV, Vidic J, Soldatkin AP, Martelet C, Pajot E, Jaffrezic-Renault N. Stimulation of human olfactory receptor 17-40 with odorants probed by surface plasmon resonance. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:807-14. [DOI: 10.1007/s00249-008-0272-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 01/10/2008] [Accepted: 01/17/2008] [Indexed: 11/29/2022]
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Wang Y, Sun J, Liu H, He Z. Rapidly profiling blood–brain barrier penetration with liposome EKC. Electrophoresis 2007; 28:2391-5. [PMID: 17578839 DOI: 10.1002/elps.200600631] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This report intended to study the potential of liposome EKC (LEKC) as a convenient and high-throughput screening tool to assess drug penetration across the blood-brain barrier (BBB). The retention factors (k) of 24 structurally diverse compounds were determined with LEKC and vesicle EKC (VEKC), respectively. Principal component analysis of the steady-state concentrations ratio of compounds in the brain and in the blood expressed as log BB, log k(LEKC), log k(VEKC), and other lipophilic descriptors including octanol/water partition coefficient (Clog P), octanol/water distribution coefficients (log D(7.4)), and polar surface area (PSA), showed the maximum similarity of partitioning processes in LEKC to drug penetration across the BBB. Furthermore, the log BB were correlated with the above five lipophilic descriptors, and the results showed that log k(LEKC) gave the better correlation coefficient (r(2) = 0.811, p <0.0001) than those of log D(7.4), Clog P, PSA, and log k(VEKC) (r(2) = 0.730, 0.672, 0.627, and 0.620, p <0.0001). This is the first report of the use of LEKC as a promising rapid tool to profile drug penetration across the BBB.
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Affiliation(s)
- Yongjun Wang
- Department of Biopharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, PR China
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Bilek G, Kremser L, Blaas D, Kenndler E. Analysis of liposomes by capillary electrophoresis and their use as carrier in electrokinetic chromatography. J Chromatogr B Analyt Technol Biomed Life Sci 2006; 841:38-51. [PMID: 16682264 DOI: 10.1016/j.jchromb.2006.03.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Revised: 03/07/2006] [Accepted: 03/15/2006] [Indexed: 11/21/2022]
Abstract
This contribution reviews work about liposomes in the context of electrically driven separation methods in the capillary format. The discussion covers four topics. The one broaches the application of liposomes as pseudo-stationary phases or carriers in vesicle or liposome electrokinetic chromatography (EKC) in the way as microemulsions and micelles are used; it includes the chromatographic use of liposomal bilayers as stationary phases attached to the wall for capillary electrochromatography (CEC). The second topic is the characterization and separation of liposomes as analytes by capillary electrophoresis (CE). Then the determination of distribution coefficients and binding constants between liposomes and ligands is discussed, and finally work dealing with peptides and proteins are reviewed with lipid bilayers as constituents of the electrically driven separation system.
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Affiliation(s)
- Gerhard Bilek
- Institute for Analytical Chemistry, University of Vienna, Währingerstrasse 38, A-1090 Vienna, Austria
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Abstract
Systems biology depends on a comprehensive assignment and characterization of the interactions of proteins and polypeptides (functional proteomics) and of other classes of biomolecules in a given organism. High‐capacity screening methods are in place for ligand capture and interaction screening, but a detailed dynamic characterization of molecular interactions under physiological conditions in efficiently separated mixtures with minimal sample consumption is presently provided only by electrophoretic interaction analysis in capillaries, affinity CE (ACE). This has been realized in different fields of biology and analytical chemistry, and the resulting advances and uses of ACE during the last 2.5 years are covered in this review. Dealing with anything from small divalent metal ions to large supramolecular assemblies, the applications of ACE span from low‐affinity binding of broad specificity being exploited in optimizing selectivity, e.g., in enantiomer analysis to miniaturized affinity technologies, e.g., for fast processing immunoassay. Also, approaches that provide detailed quantitative characterization of analyte–ligand interaction for drug, immunoassay, and aptamer development are increasingly important, but various approaches to ACE are more and more generally applied in biological research. In addition, the present overview emphasizes that distinct challenges regarding sensitivity, parallel processing, information‐rich detection, interfacing with MS, analyte recovery, and preparative capabilities remain. This will be addressed by future technological improvements that will ensure continuing new applications of ACE in the years to come.
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Affiliation(s)
- Christian Schou
- Department of Autoimmunology, Statens Serum Institute, Copenhagen, Denmark
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Abstract
Compared to MEKC, the presence of a water-immiscible oil phase in the microemulsion droplets of microemulsion EKC (MEEKC) gives rise to some special properties, such as enhanced solubilization capacity and enlarged migration window, which could allow for the improved separation of various hydrophobic and hydrophilic compounds, with reduced sample pretreatment steps, unique selectivities and/or higher efficiencies. Typically, stable and optically clear oil-in-water microemulsions containing a surfactant (SDS), oil (octane or heptane), and cosurfactant (1-butanol) in phosphate buffer are employed as separation media in conventional MEEKC. However, in recent years, the applicability of reverse MEEKC (water-in-oil microemulsions) has also been demonstrated, such as for the enhanced separation of highly hydrophobic substances. Also, during the past few years, the development and application of MEEKC for the separation of chiral molecules has been expanded, based on the use of enantioselective microemulsions that contained a chiral surfactant or chiral alcohol. On the other hand, the application of MEEKC for the characterization of the lipophilicity of chemical substances remains an active and important area of research, such as the use of multiplex MEEKC for the high-throughput determination of partition coefficients (log P values) of pharmaceutical compounds. In this review, recent applications of MEEKC (covering the period from 2003 to 2005) are reported. Emphases are placed on the discussion of MEEKC in the separation of chiral molecules and highly hydrophobic substances, as well as in the determination of partition coefficients, followed by a survey of recent applications of MEEKC in the analysis of pharmaceuticals, cosmetics and health-care products, biological and environmental compounds, plant materials, and foods.
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Affiliation(s)
- Carmen W Huie
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
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