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El-Semary MS, Belal F, El-Emam AA, Rabie Shehab El-Din EM, El-Masry AA. Ginseng root extract-mediated synthesis of monodisperse silver nanoparticles as a fluorescent probe for the spectrofluorometric determination of nilvadipine; Evaluation of remarkable anti-bacterial, anti-fungal and in-vitro cytotoxic activities. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 311:124017. [PMID: 38354677 DOI: 10.1016/j.saa.2024.124017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 02/16/2024]
Abstract
Nanoparticles are a boon for humanity because of their improved functionality and unlimited potential applications. Considering this significance, the proposed study introduced a simple, fast and eco-friendly method for synthesis of fluorescent silver nanoparticles (Ag-NPs) using Panax Ginseng root extract as a reducing and capping agent. Synthesis of Ag-NPs was performed in one step within three minutes utilizing microwave irradiation. The resulting Ag-NPs were characterized using various microscopic and spectroscopic techniques such as, Transmission Electron Microscope (TEM), UV/Visible spectroscopy, Fourier Transform Infrared Spectroscopy(FTIR) and Energy Dispersive X-ray analysis (EDX). The prepared Ag-NPs, which act as a fluorescent nano-probe with an emission band at 416 nm after excitation at 331 nm, were used to assay nilvadipine (NLV) spectrofluorimetrically in its pharmaceutical dosage form with good sensitivity and reproducibility. The proposed study is based on the ability of NLV to quantitatively quench the native Ag-NPs fluorescence, forming a ground state complex as a result of static quenching and an inner filter mechanism. The suggested approach displayed a satisfactory linear relationship throughout a concentration range of 5.0 μM - 100.0 μM, with LOD and LOQ values of 1.18 μM and 3.57 μM, respectively. Validation of the suggested approach was examined in accordance with ICH recommendations. In addition, the anti-bacterial and anti-fungal activities of the prepared nanoparticles were investigated, and they demonstrated effective anti-microbial activities and opened a future prospective to combat future antibiotic resistance. Finally, in-vitro cytotoxicity assay of Ag-NPs against normal and cancerous human cell lines was studied using MTT assay. The results proved the potential use of the produced Ag-NPs as an adjunct to anticancer treatment or for drug delivery without significantly harming healthy human cells.
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Affiliation(s)
- Mariam S El-Semary
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, 35516 Mansoura, Egypt.
| | - F Belal
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Mansoura University, 35516 Mansoura, Egypt
| | - Ali A El-Emam
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, 35516 Mansoura, Egypt
| | | | - Amal A El-Masry
- Department of Medicinal Chemistry, Faculty of Pharmacy, Mansoura University, 35516 Mansoura, Egypt.
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2
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Matsuda R, Bi C, Anguizola J, Sobansky M, Rodriguez E, Vargas Badilla J, Zheng X, Hage B, Hage DS. Studies of metabolite-protein interactions: a review. J Chromatogr B Analyt Technol Biomed Life Sci 2014; 966:48-58. [PMID: 24321277 PMCID: PMC4032809 DOI: 10.1016/j.jchromb.2013.11.043] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 11/14/2013] [Accepted: 11/18/2013] [Indexed: 11/25/2022]
Abstract
The study of metabolomics can provide valuable information about biochemical pathways and processes at the molecular level. There have been many reports that have examined the structure, identity and concentrations of metabolites in biological systems. However, the binding of metabolites with proteins is also of growing interest. This review examines past reports that have looked at the binding of various types of metabolites with proteins. An overview of the techniques that have been used to characterize and study metabolite-protein binding is first provided. This is followed by examples of studies that have investigated the binding of hormones, fatty acids, drugs or other xenobiotics, and their metabolites with transport proteins and receptors. These examples include reports that have considered the structure of the resulting solute-protein complexes, the nature of the binding sites, the strength of these interactions, the variations in these interactions with solute structure, and the kinetics of these reactions. The possible effects of metabolic diseases on these processes, including the impact of alterations in the structure and function of proteins, are also considered.
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Affiliation(s)
- Ryan Matsuda
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Cong Bi
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Jeanethe Anguizola
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Matthew Sobansky
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Elliott Rodriguez
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - John Vargas Badilla
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Xiwei Zheng
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - Benjamin Hage
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA
| | - David S Hage
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA.
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3
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Analysis of drug interactions with very low density lipoprotein by high-performance affinity chromatography. Anal Bioanal Chem 2014; 406:6203-11. [PMID: 25103529 DOI: 10.1007/s00216-014-8081-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 07/23/2014] [Accepted: 07/29/2014] [Indexed: 11/30/2022]
Abstract
High-performance affinity chromatography (HPAC) was utilized to examine the binding of very low density lipoprotein (VLDL) with drugs, using R/S-propranolol as a model. These studies indicated that two mechanisms existed for the binding of R- and S-propranolol with VLDL. The first mechanism involved non-saturable partitioning of these drugs with VLDL, which probably occurred with the lipoprotein's non-polar core. This partitioning was described by overall affinity constants of 1.2 (±0.3) × 10(6) M(-1) for R-propranolol and 2.4 (±0.6) × 10(6) M(-1) for S-propranolol at pH 7.4 and 37 °C. The second mechanism occurred through saturable binding by these drugs at fixed sites on VLDL, such as represented by apolipoproteins on the surface of the lipoprotein. The association equilibrium constants for this saturable binding at 37 °C were 7.0 (±2.3) × 10(4) M(-1) for R-propranolol and 9.6 (±2.2) × 10(4) M(-1) for S-propranolol. Comparable results were obtained at 20 and 27 °C for the propranolol enantiomers. This work provided fundamental information on the processes involved in the binding of R- and S-propranolol to VLDL, while also illustrating how HPAC can be used to evaluate relatively complex interactions between agents such as VLDL and drugs or other solutes.
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4
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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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5
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Sobansky MR, Hage DS. Identification and analysis of stereoselective drug interactions with low-density lipoprotein by high-performance affinity chromatography. Anal Bioanal Chem 2012; 403:563-71. [PMID: 22354572 DOI: 10.1007/s00216-012-5816-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/21/2012] [Accepted: 01/31/2012] [Indexed: 11/27/2022]
Abstract
Columns containing immobilized low-density lipoprotein (LDL) were prepared for the analysis of drug interactions with this agent by high-performance affinity chromatography (HPAC). R/S-Propranolol was used as a model drug for this study. The LDL columns gave reproducible binding to propranolol over 60 h of continuous use in the presence of pH 7.4 0.067 M potassium phosphate buffer. Experiments conducted with this type of column through frontal analysis indicated that two types of interactions were occurring between R-propranolol and LDL, while only a single type of interaction was observed between S-propranolol and LDL. The first type of interaction, which was seen for both enantiomers, involved non-saturable binding; this interaction had an overall affinity (nK(a)) of 1.9 (±0.1) × 10(5) M(-1) for R-propranolol and 2.7 (±0.2) × 10(5) M(-1) for S-propranolol at 37 °C. The second type of interaction was observed only for R-propranolol and involved saturable binding that had an association equilibrium constant (K(a)) of 5.2 (±2.3) × 10(5) M(-1) at 37 °C. Similar differences in binding behavior were found for the two enantiomers at 20 °C and 27 °C. This is the first known example of stereoselective binding of drugs by LDL or other lipoproteins. This work also illustrates the ability of HPAC to be used as a tool for characterizing mixed-mode interactions that involve LDL and related binding agents.
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Affiliation(s)
- Matthew R Sobansky
- Chemistry Department, University of Nebraska, Lincoln, NE 68588-0304, USA
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6
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Chen S, Sobansky MR, Hage DS. Analysis of drug interactions with high-density lipoprotein by high-performance affinity chromatography. Anal Biochem 2009; 397:107-14. [PMID: 19833090 DOI: 10.1016/j.ab.2009.10.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/02/2009] [Accepted: 10/09/2009] [Indexed: 10/20/2022]
Abstract
Columns containing immobilized lipoproteins were prepared for the analysis of drug interactions with these particles by high-performance affinity chromatography (HPAC). This approach was evaluated by using it to examine the binding of high-density lipoprotein (HDL) to the drugs propranolol and verapamil. HDL was immobilized by the Schiff base method onto silica and gave HPAC columns with reproducible binding to propranolol over 4-5days of continuous operation at pH 7.4. Frontal analysis experiments indicated that two types of interaction were occurring between R- or S-propranolol and HDL at 37 degrees C: saturable binding with an association equilibrium constant (K(a)) of 1.1-1.9x10(5)M(-1) and nonsaturable binding with an overall affinity constant (n K(a)) of 3.7-4.1x10(4)M(-1). Similar results were found at 4 and 27 degrees C. Verapamil also gave similar behavior, with a K(a) of 6.0x10(4) M(-1) at 37 degrees C for the saturable sites and an n K(a) for the nonsaturable sites of 2.5x10(4)M(-1). These measured affinities gave good agreement with solution phase values. The results indicated that HPAC can be used to study drug interactions with HDL, providing information that should be valuable in obtaining a better description of how drugs are transported within the body.
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Affiliation(s)
- Sike Chen
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, USA
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7
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Escuder-Gilabert L, Martínez-Gómez MA, Villanueva-Camañas RM, Sagrado S, Medina-Hernández MJ. Microseparation techniques for the study of the enantioselectivity of drug-plasma protein binding. Biomed Chromatogr 2009; 23:225-38. [DOI: 10.1002/bmc.1134] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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8
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Abdine H, Belal F, Gadkariem EA, Zoman N. STABILITY STUDY OF NILVADIPINE IN BULK DRUG AND PHARMACEUTICAL CAPSULES BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-100107731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- H. Abdine
- a Department of Pharmaceutical Chemistry , College of Pharmacy, King Saud University , P. O. Box 2457, Riyadh , 11451 , Saudi Arabia
| | - F. Belal
- b Department of Pharmaceutical Chemistry , College of Pharmacy, King Saud University , P. O. Box 2457, Riyadh , 11451 , Saudi Arabia
| | - E. A. Gadkariem
- a Department of Pharmaceutical Chemistry , College of Pharmacy, King Saud University , P. O. Box 2457, Riyadh , 11451 , Saudi Arabia
| | - N. Zoman
- a Department of Pharmaceutical Chemistry , College of Pharmacy, King Saud University , P. O. Box 2457, Riyadh , 11451 , Saudi Arabia
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9
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Liu Y, Lai X, Ling X, Zhao Y, Cui J. Interactions Between Thrombin with Flavonoids from Abelmoschus manihot (L.) Medicus by CZE. Chromatographia 2006. [DOI: 10.1365/s10337-006-0841-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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10
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Ostergaard J, Heegaard NHH. Bioanalytical interaction studies executed by preincubation affinity capillary electrophoresis. Electrophoresis 2006; 27:2590-608. [PMID: 16732622 DOI: 10.1002/elps.200600047] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The versatility of CE is beneficial for the study of many types of molecular interactions, because different experimental designs can be made to suit the characteristics of a particular interaction. A very versatile starting point is the preequilibration type of affinity CE that has been used extensively for characterizing biomolecular interactions in the last 15 years. We review this field here and include a comprehensive overview of the existing preincubation ACE modes including their advantages and limitations as well as the methodological developments and applications within the bioanalytical field.
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Affiliation(s)
- Jesper Ostergaard
- Department of Pharmaceutics and Analytical Chemistry, The Danish University of Pharmaceutical Sciences, Copenhagen, Denmark.
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11
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Owen RL, Strasters JK, Breyer ED. Lipid vesicles in capillary electrophoretic techniques: characterization of structural properties and associated membrane-molecule interactions. Electrophoresis 2005; 26:735-751. [PMID: 15714573 DOI: 10.1002/elps.200410288] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This paper reviews the use of lipid vesicles as model membranes in capillary electrophoresis (CE). The history and utility of CE in the characterization of microparticles is summarized, focusing on the application of colloidal electromigration theories to lipid vesicles. For instance, CE experiments have been used to characterize the size, surface properties, enclosed volumes, and electrophoretic mobilities of lipid vesicles and of lipoprotein particles. Several techniques involving small molecules or macromolecules separated in the presence of lipid vesicles are discussed. Interactions between the analytes and the lipid vesicles - acting as a pseudostationary phase or coated stationary phase in electrokinetic chromatography (EKC) - can be used to obtain additional information on the characteristics of the vesicles and analytes, and to study the biophysical properties of membrane-molecule interactions in lipid vesicles and lipoproteins. Different methods of determining binding constants by EKC are reviewed, along with the relevant binding constant calculations and a discussion of the application and limitations of these techniques as they apply to lipid vesicle systems.
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Affiliation(s)
- Rebecca L Owen
- Georgia State University, Department of Chemistry, Atlanta, GA 30302-4098, USA
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12
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Bertucci C, Bartolini M, Gotti R, Andrisano V. Drug affinity to immobilized target bio-polymers by high-performance liquid chromatography and capillary electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 797:111-29. [PMID: 14630146 DOI: 10.1016/j.jchromb.2003.08.033] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review addresses the use of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) as affinity separation methods to characterise drugs or potential drugs-bio-polymer interactions. Targets for the development of new drugs such as enzymes (IMERs), receptors, and membrane proteins were immobilized on solid supports. After the insertion in the HPLC system, these immobilized bio-polymers were used for the determination of binding constants of specific ligands, substrates and inhibitors of pharmaceutical interest, by frontal analyses and zonal elution methods. The most used bio-polymer immobilization techniques and methods for assessing the amount of active immobilized protein are reported. Examples of increased stability of immobilized enzymes with reduced amount of used protein were shown and the advantages in terms of recovery for reuse, reproducibility and on-line high-throughput screening for potential ligands are evidenced. Dealing with the acquisition of relevant pharmacokinetic data, examples concerning human serum albumin binding studies are reviewed. In particular, papers are reported in which the serum carrier has been studied to monitor the enantioselective binding of chiral drugs and the mutual interaction between co-administered drugs by CE and HPLC. Finally CE, as merging techniques with very promising and interesting application of microscale analysis of drugs' binding parameters to immobilized bio-polymers is examined.
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Affiliation(s)
- C Bertucci
- Dipartimento di Scienze Farmaceutiche, Università di Bologna, Via Belmeloro 6, 40126 Bologna, Italy
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13
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Kuroda Y, Watanabe Y, Shibukawa A, Nakagawa T. Role of phospholipids in drug-LDL bindings as studied by high-performance frontal analysis/capillary electrophoresis. J Pharm Biomed Anal 2003; 30:1869-77. [PMID: 12485729 DOI: 10.1016/s0731-7085(02)00530-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The binding study between basic drugs ((S)-verapamil (VER) and (S)-propranolol (PRO)) and phospholipid liposomes was performed by using high-performance frontal analysis/capillary electrophoresis (HPFA/CE) in order to investigate the effect of oxidative modification of low-density lipoprotein (LDL) upon drug-binding affinity from molecule-based viewpoint. 1-Palmitoyl-2-oleoyl-phosphatidylcholine (POPC, 16:0, 18:1), 1-palmitoyl-2-linoleoyl-phosphatidylcholine (PLPC, 16:0, 18:2), dilauloyl-phosphatidylcholine (DLaPC, 12:0, 12:0), 1-palmitoyl-2-oleoyl-phosphatidyl-glycerol (POPG, 16:0, 18:1), and 1-palmitoyl-sn-glycero-3-phosphocholine (monoPPC, 16:0) were used to prepare the model liposomes. At physiological pH (pH 7.4), the model liposome prepared from POPG+POPC had negative net charges, while the total net charge of the other model liposomes (POPC liposome, PLPC liposome, DLaPC liposome, and monoPPC+POPC liposome) was zero. The drug and the model liposome mixed solutions were subjected to HPFA/CE, and the total binding affinities (nK) were calculated. The nK values of VER and PRO to POPG+POPC liposome were more than six and 10 times higher than those of other liposomes, respectively. On the other hand, the nK values of the model drugs to POPC liposome, PLPC liposome, DLaPC liposome and monoPPC+POPC liposome showed small differences less than twice. These results indicate that the electrostatic interaction plays an important effect on drug-liposome binding, and suggest that the increase in the negative charge of LDL phospholipids gives more significant effect on the drug-binding affinity of the basic drugs than the acyl-chain structure.
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Affiliation(s)
- Yukihiro Kuroda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Østergaard J, Schou C, Larsen C, Heegaard NHH. Evalution of capillary electrophoresis-frontal analysis for the study of low molecular weight drug-human serum albumin interactions. Electrophoresis 2002; 23:2842-53. [PMID: 12207290 DOI: 10.1002/1522-2683(200209)23:17<2842::aid-elps2842>3.0.co;2-b] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Capillary electrophoresis frontal analysis was applied to 12 low molecular weight compounds including 8 drug substances displaying a range of different properties with respect to binding affinity, binding location, structure, lipophilicity, charge at physiological pH, and electrophoretic mobility. It was found that capillary electrophoresis frontal analysis can be used as a general method to study and quantify drug-human serum albumin interactions. The binding parameters obtained were consistent with literature values. Dextran was in some cases added to the run buffer to improve separation of the drug and human serum albumin plateau peaks. Results indicate that mobility differences between free and complexed human serum albumin give rise to only minor errors. Capillary electrophoresis frontal analysis was also found applicable to the study of human serum albumin drug displacement reactions. Low sensitivity of the UV-detection system was found to be the major limitation of capillary electrophoresis frontal analysis. The method is simple, and minimal effort has to be put into method development, which makes it well suited for screening in early drug development.
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Affiliation(s)
- Jesper Østergaard
- Department of Analytical and Pharmaceutical Chemistry, Royal Danish School of Pharmacy
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Heegaard NHH, Nissen MH, Chen DDY. Applications of on-line weak affinity interactions in free solution capillary electrophoresis. Electrophoresis 2002; 23:815-22. [PMID: 11920866 DOI: 10.1002/1522-2683(200203)23:6<815::aid-elps815>3.0.co;2-v] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on-line affinity capillary electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g., drug enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On-line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities.
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Affiliation(s)
- Niels H H Heegaard
- Department of Autoimmunology, Bldg. 81, Rm. 536, Statens Serum Institut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
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16
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Shibukawa A, Ishizawa N, Kimura T, Sakamoto Y, Ogita K, Matsuo Y, Kuroda Y, Matayatsu C, Nakagawa T, Wainer IW. Plasma protein binding study of oxybutynin by high-performance frontal analysis. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 768:177-88. [PMID: 11939551 DOI: 10.1016/s0378-4347(01)00497-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Plasma protein binding of oxybutynin (OXY) was investigated quantitatively and enantioselectively using high-performance frontal analysis (HPFA). An on-line HPLC system which consists of HPFA column, extraction column and analytical column was developed to determine the unbound concentrations of OXY enantiomers in human plasma, in human serum albumin (HSA) solutions, and in human alpha1-acid glycoprotein (AGP) solutions. OXY is bound in human plasma strongly and enantioselectively. The bound drug fraction in human plasma containing 2-10 microM (R)- or (S)-OXY was higher than 99%, and the unbound fraction of (R)-OXY was 1.56 times higher than that of (S)-isomer. AGP plays the dominant role in this strong and enantioselective plasma protein binding. The total binding affinities (nK) of (R)- and (S)-OXY to AGP were 6.86 x 10(6) and 1.53 x 10(7) M(-1), respectively, while the nK values of (R)- and (S)-OXY to HSA were 2.64 x 10(4) and 2.19 x 10(-4) M(-1), respectively. The binding affinity of OXY to AGP is much higher than that to HSA, and shows high enantioselectivity (SIR ratio of nK values is 2.2). It was found that both enantiomers are bound competitively at the same binding site on an AGP molecule. The binding property between OXY and low density lipoprotein (LDL) was investigated by using the frontal analysis method incorporated in high-performance capillary electrophoresis (HPCE/FA). It was found the binding is non-saturable and non-enantioselective.
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Affiliation(s)
- Akimasa Shibukawa
- Graduate School of Pharmaceutical Sciences, Kyoto University, Japan.
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17
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Tanaka Y, Terabe S. Estimation of binding constants by capillary electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 768:81-92. [PMID: 11939561 DOI: 10.1016/s0378-4347(01)00488-1] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Capillary electrophoresis (CE) has become a useful technique for measuring binding constants. This review is focused on recent trends in the estimation of binding constants by affinity CE. First, we introduce several mathematical equations in which it is assumed that the stoichiometry of the binding between drug and protein is 1:1 as a simple model. In order to calculate accurate binding constants by affinity CE, several experimental considerations are described in this review. In addition, some recent methodologies, such as partial filling technique and multiple-step ligand injection method, are introduced. Among research publications within 3 years, recent applications for determining binding constants are reviewed.
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Affiliation(s)
- Yoshihide Tanaka
- Department of Analytical Chemistry, Nippon Boehringer Ingelheim, Kawanishi, Hyogo, Japan.
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18
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Ohnishi T, Mohamed NAL, Shibukawa A, Kuroda Y, Nakagawa T, El Gizawy S, Askal HF, El Kommos ME. Frontal analysis of drug-plasma lipoprotein binding using capillary electrophoresis. J Pharm Biomed Anal 2002; 27:607-14. [PMID: 11755761 DOI: 10.1016/s0731-7085(01)00569-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
High performance frontal analysis coupled with capillary electrophoresis (HPFA/CE) was applied to the ultramicroanalysis of enantioselective binding of drug to plasma lipoproteins. A small volume (ca. 80 nl) of (R)- or (S)-propranolol (PRO, 25-150 microM) and human high-density lipoprotein (HDL, 2.63 g/l) or human low-density lipoprotein (LDL, 4.37 g/l) mixed solution, which was in the state of binding equilibrium, was introduced hydrodynamically into a non-coated fused silica capillary. Positively charged unbound PRO enantiomers migrated toward cathodic end much faster than negatively charged lipoproteins and the bound form. Once unbound PRO migrated apart from lipoprotein, the bound PRO was quickly released from the lipoprotein to maintain the binding equilibrium. Thus, PRO migrated as a zone in the capillary, giving a peak with a plateau region, where the concentration is the same as the unbound PRO concentration in the original sample solution. The unbound PRO concentration calculated form the plateau height agreed with that determined by a conventional ultrafiltration method used as a reference method. It was found that the bindings of PRO to HDL and PRO to LDL were not enantioselective, while the total binding affinity of PRO to LDL (4.01 x 10(5) per M) was 17 times higher than that of PRO-HDL binding (2.38 x 10(4) per M).
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Affiliation(s)
- Takanori Ohnishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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19
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Belal F, Abdine H, Zoman N. Voltammetric determination of nilvadipine in dosage forms and spiked human urine. J Pharm Biomed Anal 2001; 26:585-92. [PMID: 11516909 DOI: 10.1016/s0731-7085(01)00485-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The voltammetric behaviour of nilvadipine was studied adopting direct-current, differential-pulse and alternating current polarography. Nilvadipine-being nitroderivative-exhibited well-defined cathodic waves over the whole pH range in Britton-Robinson buffers. At pH 5, the diffusion-current constant, (Id) was 4.78. The current-concentration plots are rectilinear over the range 1.5-20 and 0.2-10 microg/ml using the direct current and differential pulse-polarographic techniques with minimum detectability of 0.05 microg/ml (1.3 x 10(-7) M) using the latter technique. The proposed method was applied to commercial capsules containing the drug. The percentage recoveries were in agreement with those obtained by a reference method. Furthermore, the method was applied to spiked human urine, the percentage recovery was 95.54+/-2.137.
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Affiliation(s)
- F Belal
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, P.O. Box 2457, Riyadh 11451, Saudi Arabia.
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Abstract
This review article with 223 references describes recent developments in capillary electrophoresis (CE) of proteins and covers papers published during last two years, from the previous review (V. Dolnik, Electrophoresis 1999, 20, 3106-3115) through Spring 2001. It describes the topics related to CE of proteins including modeling of the electrophoretic properties of proteins, sample pretreatment, wall coatings, improving selectivity, detection, special electrophoretic techniques, and applications.
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Affiliation(s)
- V Dolnik
- Molecular Dynamics, Sunnyvale, CA 94085, USA.
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Kuroda Y, Cao B, Shibukawa A, Nakagawa T. Effect of oxidation of low-density lipoprotein on drug binding affinity studied by high performance frontal analysis-capillary electrophoresis. Electrophoresis 2001; 22:3401-7. [PMID: 11669517 DOI: 10.1002/1522-2683(200109)22:16<3401::aid-elps3401>3.0.co;2-f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effect of oxidation of low-density lipoprotein (LDL) on the enantioselective drug binding affinity was investigated using high performance frontal analysis--capillary electrophoresis (HPFA-CE). Verapamil and nilvadipine enantiomers were used as the chiral model drugs. LDL was oxidized with copper sulfate for 0, 0.5, 1, 2, and 12 h at 37 degrees C. The HPFA-CE method enabled microdetermination of unbound drug concentrations in native and oxidized LDL solutions. It was found that the bindings between LDL and the model drugs were not enantioselective at any oxidation stage. The total binding affinity (nK) between LDL and verapamil enantiomers was increased by 3.3-, 4.6-, 7.0-, and 19-fold after 0.5, 1, 2, and 12 h oxidation, respectively, whereas the nK value between nilvadipine and LDLwas increased by 1.3-, 1.4-, 1.4-, and 1.7-fold in the same reaction times, respectively. These results indicate that the LDL oxidation enhances the drug binding affinity, and the affinity of verapamil is increased more sensitively than that of nilvadipine. The nK value of each model drug increased steeply after the first 2 h oxidation, followed by the gradual increase after the next 10 h oxidation. It is considered that the net increase in the negative charges and/or the formation of hydroperoxides in the first 2 h oxidation enhances the drug-LDL binding more significantly than the formation of aldehydes or Schiff bases in the following 10 h oxidation.
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Affiliation(s)
- Y Kuroda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Japan
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22
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Abstract
Apparent equilibrium constants for molecular association (e.g., association constants, binding constants, dissociation constants, partition coefficients) can be determined with a variety of different capillary electrophoresis (CE) approaches. In many cases, the investigated association behavior is between a smaller molecule or ion (i.e., the solute, drug, or analyte of interest) and a larger entity (e.g., proteins, micelles, polymers, chiral selectors such as cyclodextrins, etc.). Each experimental approach has advantages and disadvantages. Frequently, it is the nature of the system being evaluated that determines the optimal experimental approach. Six different CE-based techniques for evaluating binding constants are reviewed. Examples of each method, and recent references on its use are given.
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Kuroda Y, Kita Y, Shibukawa A, Nakagawa T. Role of biantennary glycans and genetic variants of human alpha1-acid glycoprotein in enantioselective binding of basic drugs as studied by high performance frontal analysis/capillary electrophoresis. Pharm Res 2001; 18:389-93. [PMID: 11442281 DOI: 10.1023/a:1011023518144] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To establish a clear understanding of the role of biantennary branching glycans and genetic variants of alpha1-acid glycoprotein (AGP) in enantioselective bindings of basic drug. METHODS Human native AGP was separated using concanavalin A affinity chromatography into two subfractions, the unretained fraction (UR-AGP, defect of biantennary glycan) and the retained fraction (R-AGP, possessing biantennary glycan(s)). Imminodiacetate-copper (II) affinity chromatography was used to separate human native AGP into A variant and a mixture of F1 and S variants (F1*S variants). The mixed solutions of the (R)- or (S)-isomer of the model drugs (15 microM disopyramide (DP) or 30 microM verapamil (VER)) and 40 microM of respective AGP species were subjected to high-performance frontal analysis/capillary electrophoresis (HPFA/CE) to determine the unbound drug concentrations. RESULTS The unbound concentrations (Cu) of DP in UR-AGP solutions were lower than those in R-AGP solutions, whereas there was no significant difference in the enantiomeric ratios (Cu(R)/Cu(S)) of DP between UR- and R-AGP solutions. In case of genetic variant, the Cu(R)/Cu(S) values of DP in F1*S and A solutions were 1.07 and 2.37, respectively. On the other hand, the enantiomeric ratio of VER in F1*S and A variant solutions were 0.900 and 0.871, respectively. CONCLUSIONS The biantennary glycan structures are related to binding affinity of DP to AGP, but not responsible for the enantioselectivity. Genetic variants give significant effect on the enantioselectivity in DP binding, but not in VER binding.
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Affiliation(s)
- Y Kuroda
- Graduate School of Pharmaceutical Sciences, Kyoto University, Japan
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Abstract
Use of the specificity of (bio)interactions can effectively overcome the selectivity limitation faced in capillary electrophoresis (CE), and the resulting technique usually is referred to as affinity capillary electrophoresis (ACE). Despite the high selectivity of ACE, several important problems still need to be addressed. A major issue in all CE separations, including ACE, is the concentration detection limit. Using UV detection, this is usually in the order of 10(-6) M whereas laser-induced fluorescence (LIF) detection can provide detection limits down to the sub-10(-10) M range. However, a marked disadvantage of LIF is that labeling of the analytes is usually required, which might change the interaction behavior of the solutes under investigation. Additionally, labeling reactions at sub-10(-10) M concentration levels are certainly not trivial and often difficult to perform quantitatively. Alternative and universal detection approaches, particularly mass spectrometric (MS) detection, look very promising but (A) CE-MS techniques are still far from routine application. Important future progress in sensitive detection strategies is likely to increase the use of ACE in the future.
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Affiliation(s)
- R M Guijt-van Duijn
- Delft University of Technology, Department of Analytical Biotechnology, The Netherlands
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