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Maculewicz J, Świacka K, Kowalska D, Stepnowski P, Stolte S, Dołżonek J. In vitro methods for predicting the bioconcentration of xenobiotics in aquatic organisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 739:140261. [PMID: 32758962 DOI: 10.1016/j.scitotenv.2020.140261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/10/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
The accumulation of anthropogenic chemical substances in aquatic organisms is an immensely important issue from the point of view of environmental protection. In the context of the increasing number and variety of compounds that may potentially enter the environment, there is a need for efficient and reliable solutions to assess the risks. However, the classic approach of testing with fish or other animals is not sufficient. Due to very high costs, significant time and labour intensity, as well as ethical concerns, in vivo methods need to be replaced by new laboratory-based tools. So far, many models have been developed to estimate the bioconcentration potential of chemicals. However, most of them are not sufficiently reliable and their predictions are based on limited input data, often obtained with doubtful quality. The octanol-water partition coefficient is still often used as the main laboratory tool for estimating bioconcentration. However, according to current knowledge, this method can lead to very unreliable results, both for neutral species and, above all, for ionic compounds. It is therefore essential to start using new, more advanced and credible solutions on a large scale. Over the last years, many in vitro methods have been newly developed or improved, allowing for a much more adequate estimation of the bioconcentration potential. Therefore, the aim of this work was to review the most recent laboratory methods for assessing the bioconcentration potential and to evaluate their applicability in further research.
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Affiliation(s)
- Jakub Maculewicz
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Klaudia Świacka
- Department of Experimental Ecology of Marine Organisms, Institute of Oceanography, University of Gdansk, Av. Pilsudskiego 46, 81-378 Gdynia, Poland
| | - Dorota Kowalska
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Piotr Stepnowski
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Stefan Stolte
- Faculty of Environmental Sciences, Department of Hydrosciences, Institute of Water Chemistry, Technische Universität Dresden, Bergstrasse 66, 01069 Dresden, Germany
| | - Joanna Dołżonek
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
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Yue Z, Li C, Voth GA, Swanson JMJ. Dynamic Protonation Dramatically Affects the Membrane Permeability of Drug-like Molecules. J Am Chem Soc 2019; 141:13421-13433. [PMID: 31382734 DOI: 10.1021/jacs.9b04387] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Permeability (Pm) across biological membranes is of fundamental importance and a key factor in drug absorption, distribution, and development. Although the majority of drugs will be charged at some point during oral delivery, our understanding of membrane permeation by charged species is limited. The canonical model assumes that only neutral molecules partition into and passively permeate across membranes, but there is mounting evidence that these processes are also facile for certain charged species. However, it is unknown whether such ionizable permeants dynamically neutralize at the membrane surface or permeate in their charged form. To probe protonation-coupled permeation in atomic detail, we herein apply continuous constant-pH molecular dynamics along with free energy sampling to study the permeation of a weak base propranolol (PPL), and evaluate the impact of including dynamic protonation on Pm. The simulations reveal that PPL dynamically neutralizes at the lipid-tail interface, which dramatically influences the permeation free energy landscape and explains why the conventional model overestimates the assigned intrinsic permeability. We demonstrate how fixed-charge-state simulations can account for this effect, and propose a revised model that better describes pH-coupled partitioning and permeation. Our results demonstrate how dynamic changes in protonation state may play a critical role in the permeation of ionizable molecules, including pharmaceuticals and drug-like molecules, thus requiring a revision of the standard picture.
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Affiliation(s)
- Zhi Yue
- Department of Chemistry, James Frank Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Chenghan Li
- Department of Chemistry, James Frank Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Gregory A Voth
- Department of Chemistry, James Frank Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
| | - Jessica M J Swanson
- Department of Chemistry, James Frank Institute, and Institute for Biophysical Dynamics , The University of Chicago , Chicago , Illinois 60637 , United States
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MURAKAMI K, HORI K, MAEDA K, FUKUYAMA M, YOSHIDA Y. Adsorption and Distribution of Ions to a Bilayer Lipid Membrane. BUNSEKI KAGAKU 2018. [DOI: 10.2116/bunsekikagaku.67.581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Koji MURAKAMI
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology
| | - Kisho HORI
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology
| | - Kohji MAEDA
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology
| | - Mao FUKUYAMA
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University
| | - Yumi YOSHIDA
- Department of Chemistry and Materials Technology, Kyoto Institute of Technology
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Dotsenko AS, Dotsenko GS, Senko OV, Stepanov NA, Lyagin IV, Efremenko EN, Gusakov AV, Zorov IN, Rubtsova EA. Complex effect of lignocellulosic biomass pretreatment with 1-butyl-3-methylimidazolium chloride ionic liquid on various aspects of ethanol and fumaric acid production by immobilized cells within SSF. BIORESOURCE TECHNOLOGY 2018; 250:429-438. [PMID: 29195155 DOI: 10.1016/j.biortech.2017.11.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 06/07/2023]
Abstract
The pretreatment of softwood and hardwood samples (spruce and hornbeam wood) with 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was undertaken for further simultaneous enzymatic saccharification of renewable non-food lignocellulosic biomass and microbial fermentation of obtained sugars to ethanol and fumaric acid. A multienzyme cocktail based on cellulases and yeast or fungus cells producing ethanol and fumaric acid were the main objects of [Bmim]Cl influence studies. A complex effect of lignocellulosic biomass pretreatment with [Bmim]Cl on various aspects of the process (both action of cellulases and microbial conversion of hydrolysates to target products) was revealed. Positive effects of the pretreatment with [Bmim]Cl included decreasing the lignin content in the biomass, and increasing the effectiveness of enzymatic hydrolysis and microbial transformation of pretreated biomass. Immobilized cells of both yeasts and fungi possessed improved productive characteristics in the biotransformation of biomass pretreated with [Bmim]Cl to ethanol and fumaric acid.
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Affiliation(s)
- Anna S Dotsenko
- Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia.
| | - Gleb S Dotsenko
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Olga V Senko
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Nikolay A Stepanov
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ilya V Lyagin
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena N Efremenko
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alexander V Gusakov
- Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia; Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ivan N Zorov
- Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia; Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ekaterina A Rubtsova
- Federal Research Centre "Fundamentals of Biotechnology", Russian Academy of Sciences, Moscow 119071, Russia
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Dołżonek J, Cho CW, Stepnowski P, Markiewicz M, Thöming J, Stolte S. Membrane partitioning of ionic liquid cations, anions and ion pairs - Estimating the bioconcentration potential of organic ions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 228:378-389. [PMID: 28554027 DOI: 10.1016/j.envpol.2017.04.079] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 05/26/2023]
Abstract
Recent efforts have been directed towards better understanding the persistency and toxicity of ionic liquids (ILs) in the context of the "benign-by-design" approach, but the assessment of their bioaccumulation potential remains neglected. This paper reports the experimental membrane partitioning of IL cations (imidazolium, pyridinium, pyrrolidinium, phosphonium), anions ([C(CN)3]-, [B(CN)4]-, [FSO2)2N]-, [(C2F5)3PF3]-, [(CF3SO2)2N]-) and their combinations as a measure for estimating the bioconcentration factor (BCF). Both cations and anions can have a strong affinity for phosphatidylcholine bilayers, which is mainly driven by the hydrophobicity of the ions. This affinity is often reflected in the ecotoxicological impact. Our data revealed that the bioconcentration potential of IL cations and anions is much higher than expected from octanol-water-partitioning based estimations that have recently been presented. For some ILs, the membrane-water partition coefficient reached levels corresponding to BCFs that might become relevant in terms of the "B" (bioaccumulation potential) classification under REACH. However, this preliminary estimation need to be confirmed by in vivo bioconcentration studies.
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Affiliation(s)
- Joanna Dołżonek
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; Center for Environmental Research and Sustainable Technology (UFT), Faculty 4, University of Bremen, Leobener Strasse, 28359 Bremen, Germany.
| | - Chul-Woong Cho
- School of Chemical Engineering, Chonbuk National University, Chonbuk, Jeonju 561-756, Republic of Korea
| | - Piotr Stepnowski
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland
| | - Marta Markiewicz
- Center for Environmental Research and Sustainable Technology (UFT), Faculty 4, University of Bremen, Leobener Strasse, 28359 Bremen, Germany
| | - Jorg Thöming
- Center for Environmental Research and Sustainable Technology (UFT), Faculty 4, University of Bremen, Leobener Strasse, 28359 Bremen, Germany
| | - Stefan Stolte
- Department of Environmental Analysis, Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland; Center for Environmental Research and Sustainable Technology (UFT), Faculty 4, University of Bremen, Leobener Strasse, 28359 Bremen, Germany.
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Lopes D, Jakobtorweihen S, Nunes C, Sarmento B, Reis S. Shedding light on the puzzle of drug-membrane interactions: Experimental techniques and molecular dynamics simulations. Prog Lipid Res 2017; 65:24-44. [DOI: 10.1016/j.plipres.2016.12.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 11/30/2016] [Accepted: 12/03/2016] [Indexed: 12/20/2022]
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8
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Fan Y, Liu SS, Qu R, Li K, Liu HL. Polymyxin B sulfate inducing time-dependent antagonism of the mixtures of pesticide, ionic liquids, and antibiotics to Vibrio qinghaiensis sp.-Q67. RSC Adv 2017. [DOI: 10.1039/c6ra25843c] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the real environment, organisms are simultaneously exposed to different types of chemicals.
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Affiliation(s)
- Ye Fan
- Key Laboratory of Yangtze River Water Environment
- Ministry of Education
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Shu-Shen Liu
- Key Laboratory of Yangtze River Water Environment
- Ministry of Education
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Rui Qu
- Key Laboratory of Yangtze River Water Environment
- Ministry of Education
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Kai Li
- Key Laboratory of Yangtze River Water Environment
- Ministry of Education
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
| | - Hai-Ling Liu
- State Key Laboratory of Pollution Control and Resource Reuse
- College of Environmental Science and Engineering
- Tongji University
- Shanghai 200092
- China
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Murakami K, Hori K, Maeda K, Fukuyama M, Yoshida Y. Distribution and Adsorption of Ionic Species into a Liposome Membrane and Their Dependence upon the Species and Concentration of a Coexisting Counterion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10678-10684. [PMID: 27687781 DOI: 10.1021/acs.langmuir.6b03162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The distribution of ions into a bilayer lipid membrane (BLM) and their adsorption on the BLM are investigated by extracting a hydrophobic cation, rhodamine 6G (R6G+), into a liposome through the dialysis membrane method. R6G+ distribution mainly depends upon the concentration of the coexisting anion and its species (Cl-, Br-, BF4-, ClO4-, and picrate). On the other hand, R6G+ adsorption on the BLM surface follows the Langmuir adsorption model and is independent of the coexisting anion in the aqueous phase. We propose an extraction model of ionic species into the BLM, to explain the dependence of extraction of ionic species upon the coexisting anion. In this model, an ion is distributed with a coexisting counterion into the BLM and then forms an ion pair in the BLM. Here, the ion adsorption equilibrium on the BLM surface is independent of the species and concentration of the coexisting counterion under the same ionic strength. On the basis of this model, we estimate the distribution constant of R6G+ and anion (KD), the ion-pair formation constant in the BLM (Kip), and the R6G+ adsorption constant on the BLM surface (Kad). Even for an ultrathin membrane system, such as a BLM, R6G+ is distributed with a coexisting counterion and the distribution equilibrium of the ionic species at the water-BLM interface is analyzable similar to that at the water-organic solvent interface.
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Affiliation(s)
- Koji Murakami
- Department of Chemistry and Materials Technology and ‡Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
| | - Kisho Hori
- Department of Chemistry and Materials Technology and ‡Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
| | - Kohji Maeda
- Department of Chemistry and Materials Technology and ‡Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
| | - Mao Fukuyama
- Department of Chemistry and Materials Technology and ‡Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
| | - Yumi Yoshida
- Department of Chemistry and Materials Technology and ‡Faculty of Molecular Chemistry and Engineering, Kyoto Institute of Technology , Matsugasaki, Sakyo, Kyoto 606-8585, Japan
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Cubayachi C, Couto ROD, de Gaitani CM, Pedrazzi V, Freitas OD, Lopez RFV. Needle-free buccal anesthesia using iontophoresis and amino amide salts combined in a mucoadhesive formulation. Colloids Surf B Biointerfaces 2015; 136:1193-201. [DOI: 10.1016/j.colsurfb.2015.11.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/08/2015] [Accepted: 11/02/2015] [Indexed: 11/29/2022]
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11
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Haftka JJH, Hammer J, Hermens JLM. Mechanisms of Neutral and Anionic Surfactant Sorption to Solid-Phase Microextraction Fibers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:11053-61. [PMID: 26322866 DOI: 10.1021/acs.est.5b02901] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Octanol-water partitioning (Kow) is considered a key parameter for hydrophobicity and is often applied in the prediction of the environmental fate and exposure of neutral organic compounds. However, surfactants can create difficulties in the determination of Kow because of emulsification of both water and octanol phases. Moreover, not only is sorption behavior of ionic surfactants related to hydrophobicity, but also other interactions are relevant in sorption processes. A different approach to develop parameters that can be applied in predictive modeling of the fate of surfactants in the environment is therefore required. Distribution between solid-phase microextraction (SPME) fibers and water was used in this study to measure the affinity of surfactants to a hydrophobic phase. Fiber-water sorption coefficients of alcohol ethoxylates, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates were determined at pH 7 by equilibration of the test analytes between fiber and water. Distribution between fiber and water of anionic compounds with pKa ∼ 5 (i.e., alkyl carboxylates) was dominated by the neutral fraction. Anionic surfactants with pKa ≤ 2 (i.e., alkyl sulfates and alkyl sulfonates) showed strong nonlinear distribution to the fiber. The fiber-water sorption coefficients for alcohol ethoxylates and alkyl sulfates showed a linear trend with bioconcentration factors from the literature. Fiber-water sorption coefficients are promising as a parameter to study the effects of hydrophobicity and other potential interactions on sorption behavior of neutral and anionic surfactants.
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Affiliation(s)
- Joris J-H Haftka
- Institute for Risk Assessment Sciences , Yalelaan 104, P.O. Box 80177, Utrecht, The Netherlands
| | - Jort Hammer
- Institute for Risk Assessment Sciences , Yalelaan 104, P.O. Box 80177, Utrecht, The Netherlands
| | - Joop L M Hermens
- Institute for Risk Assessment Sciences , Yalelaan 104, P.O. Box 80177, Utrecht, The Netherlands
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12
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Gupta S, Basant N, Singh KP. Nonlinear QSAR modeling for predicting cytotoxicity of ionic liquids in leukemia rat cell line: an aid to green chemicals designing. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:12699-12710. [PMID: 25913312 DOI: 10.1007/s11356-015-4526-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/09/2015] [Indexed: 06/04/2023]
Abstract
Safety assessment and designing of safer ionic liquids (ILs) are among the priorities of the chemists and toxicologists today. Computational approaches have been considered as appropriate methods for prior safety assessment of chemicals and tools to aid in structural designing. The present study is an attempt to investigate the chemical attributes of a wide variety of ILs towards their cytotoxicity in leukemia rat cell line IPC-81 through the development of nonlinear quantitative structure-activity relationship (QSAR) models in the light of the OECD principles for QSAR development. Here, the cascade correlation network (CCN), probabilistic neural network (PNN), and generalized regression neural networks (GRNN) QSAR models were established for the discrimination of ILs in four categories of cytotoxicity and their end-point prediction using few simple descriptors. The diversity and nonlinearity of the considered dataset were evaluated through computing the Euclidean distance and Brock-Dechert-Scheinkman statistics. The constructed QSAR models were validated with external test data. The predictive power of these models was established through a variety of stringent parameters recommended in QSAR literature. The classification QSARs rendered the accuracy of >86%, and the regression models yielded correlation (R(2)) of >0.90 in test data. The developed QSAR models exhibited high statistical confidence and identified the structural elements of the ILs responsible for their cytotoxicity and, hence, could be useful tools in structural designing of safer and green ILs.
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Affiliation(s)
- Shikha Gupta
- Environmental Chemistry Division, CSIR-Indian Institute of Toxicology Research, Post Box 80, Mahatma Gandhi Marg, Lucknow, 226 001, India
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13
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Colclough N, Wenlock MC. Interpreting physicochemical experimental data sets. J Comput Aided Mol Des 2015; 29:779-94. [PMID: 26054297 DOI: 10.1007/s10822-015-9850-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/29/2015] [Indexed: 12/01/2022]
Abstract
With the wealth of experimental physicochemical data available to chemoinformaticians from the literature, commercial, and company databases an increasing challenge is the interpretation of such datasets. Subtle differences in experimental methodology used to generate these datasets can give rise to variations in physicochemical property values. Such methodology nuances will be apparent to an expert experimentalist but not necessarily to the data analyst and modeller. This paper describes the differences between common methodologies for measuring the four most important physicochemical properties namely aqueous solubility, octan-1-ol/water distribution coefficient, pK(a) and plasma protein binding highlighting key factors that can lead to systematic differences. Insight is given into how to identify datasets suitable for combining.
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Affiliation(s)
- Nicola Colclough
- Oncology and Drug Safety and Metabolism, Innovative Medicines, Mereside, AstraZeneca, Alderley Park, Macclesfield, Cheshire, SK10 4TG, UK.
| | - Mark C Wenlock
- Oncology and Drug Safety and Metabolism, Innovative Medicines, Mereside, AstraZeneca, Alderley Park, Macclesfield, Cheshire, SK10 4TG, UK
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Akmese B, Sanli S, Sanli N, Asan A. A validated RP-LC method for salmeterol and fluticasone in their binary mixtures and their stress degradation behavior under ICH-recommended stress conditions. JOURNAL OF ANALYTICAL CHEMISTRY 2014. [DOI: 10.1134/s1061934814060021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Fugit KD, Anderson BD. Dynamic, nonsink method for the simultaneous determination of drug permeability and binding coefficients in liposomes. Mol Pharm 2014; 11:1314-25. [PMID: 24628304 PMCID: PMC3993891 DOI: 10.1021/mp400765n] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/21/2014] [Accepted: 03/14/2014] [Indexed: 01/22/2023]
Abstract
Drug release from liposomal formulations is governed by a complex interplay of kinetic (i.e., drug permeability) and thermodynamic factors (i.e., drug partitioning to the bilayer surface). Release studies under sink conditions that attempt to mimic physiological conditions are insufficient to decipher these separate contributions. The present study explores release studies performed under nonsink conditions coupled with appropriate mathematical models to describe both the release kinetics and the conditions in which equilibrium is established. Liposomal release profiles for a model anticancer agent, topotecan, under nonsink conditions provided values for both the first-order rate constant for drug release and the bilayer/water partition coefficient. These findings were validated by conducting release studies under sink conditions via dynamic dialysis at the same temperature and buffer pH. A nearly identical rate constant for drug release could be obtained from dynamic dialysis data when appropriate volume corrections were applied and a mechanism-based mathematical model was employed to account for lipid bilayer binding and dialysis membrane transport. The usefulness of the nonsink method combined with mathematical modeling was further explored by demonstrating the effects of topotecan dimerization and bilayer surface charge potential on the bilayer/water partition coefficient at varying suspension concentrations of lipid and drug.
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Affiliation(s)
- Kyle D. Fugit
- Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, A323A ASTeCC
Building, Lexington, Kentucky 40506, United States
| | - Bradley D. Anderson
- Department of Pharmaceutical
Sciences, College of Pharmacy, University
of Kentucky, A323A ASTeCC
Building, Lexington, Kentucky 40506, United States
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16
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Bilayer Composition, Temperature, Speciation Effects and the Role of Bilayer Chain Ordering on Partitioning of Dexamethasone and its 21-Phosphate. Pharm Res 2013; 30:3154-69. [DOI: 10.1007/s11095-013-1143-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 07/01/2013] [Indexed: 10/26/2022]
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Ventura SPM, Gonçalves AMM, Sintra T, Pereira JL, Gonçalves F, Coutinho JAP. Designing ionic liquids: the chemical structure role in the toxicity. ECOTOXICOLOGY (LONDON, ENGLAND) 2013; 22:1-12. [PMID: 23010869 DOI: 10.1007/s10646-012-0997-x] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/07/2012] [Indexed: 06/01/2023]
Abstract
Ionic liquids (ILs) are a novel class of solvents with interesting physicochemical properties. Many different applications have been reported for ILs as alternatives to organic solvents in chemical and bioprocesses. Despite the argued advantage of having low vapor pressure, even the most hydrophobic ILs show some degree of solubility in water, allowing their dispersion into aquatic systems and raising concerns on its pollutant potential. Moreover, nowadays most widespread notion concerning the ILs toxicity is that there is a direct relationship with their hydrophobicity/lipophilicity. This work aims at enlarging the currently limited knowledge on ILs toxicity by addressing negative impacts in aquatic ecosystems and investigating the possibility of designing hydrophobic ILs of low ecotoxicity, by the manipulation of their chemical structures. The impact of aromaticity on the toxicity of different cations (pyridinium, piperidinium, pyrrolidinium and imidazolium) and hydrophobic anions (bis(trifluoromethylsulfonyl)imide [NTf(2)] and hexafluorophosphate [PF(6)]) was analysed. Concomitantly, several imidazolium-based ILs of the type [C( n )C( m )C( j )im][NTf(2)] were also studied to evaluate the effects of the position of the alkyl chain on the ILs' toxicity. For that purpose, standard assays were performed using organisms of different trophic levels, Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna, allowing to evaluate the consistency of the structure-activity relationships across different biological targets. The results here reported suggest the possibility of designing ILs with an enhanced hydrophobic character and lower toxicity, by elimination of their aromatic nature.
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Affiliation(s)
- Sónia P M Ventura
- Departamento de Química, CICECO, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
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Dobler D, Schmidts T, Klingenhöfer I, Runkel F. Ionic liquids as ingredients in topical drug delivery systems. Int J Pharm 2013; 441:620-7. [DOI: 10.1016/j.ijpharm.2012.10.035] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/12/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022]
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Lipophilicity of acidic compounds: Impact of ion pair partitioning on drug design. Bioorg Med Chem Lett 2011; 21:3550-6. [DOI: 10.1016/j.bmcl.2011.04.133] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/27/2011] [Accepted: 04/27/2011] [Indexed: 11/23/2022]
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20
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Wenlock MC, Potter T, Barton P, Austin RP. A Method for Measuring the Lipophilicity of Compounds in Mixtures of 10. ACTA ACUST UNITED AC 2011; 16:348-55. [DOI: 10.1177/1087057110396372] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lipophilicity is an important parameter for any potential drug candidate. Accurate and efficient lipophilicity measurements facilitate the development of high-quality predictive in silico models that support the design of future drugs. Lipophilicity estimates derived from the traditional 1-octanol/water shake flask techniques have been the most widely employed and are therefore the best understood. This technique can be considered to give a good measure of a compound’s lipophilicity, albeit slower and more labor intensive to run compared with some other methodologies. Herein is described and validated an efficient 1-octanol/water shake flask technique that has sufficient capacity to be run as a primary screen within the drug discovery process. This is achieved by the simultaneous measurement of the distribution coefficients of mixtures of up to 10 compounds using high-performance liquid chromatography and tandem mass spectrometry. Concerns regarding ion pair partitioning that could result in erroneous results due to interactions between compounds within a mixture are discussed.
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Affiliation(s)
- Mark C. Wenlock
- Department of Chemistry, AstraZeneca R&D Charnwood, Loughborough, Leicestershire, UK
| | - Tim Potter
- Department of Chemistry, AstraZeneca R&D Charnwood, Loughborough, Leicestershire, UK
| | - Patrick Barton
- Department of Chemistry, AstraZeneca R&D Charnwood, Loughborough, Leicestershire, UK
| | - Rupert P. Austin
- Department of Chemistry, AstraZeneca R&D Charnwood, Loughborough, Leicestershire, UK
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21
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Pham TPT, Cho CW, Yun YS. Environmental fate and toxicity of ionic liquids: a review. WATER RESEARCH 2010; 44:352-72. [PMID: 19854462 DOI: 10.1016/j.watres.2009.09.030] [Citation(s) in RCA: 568] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 08/27/2009] [Accepted: 09/12/2009] [Indexed: 05/07/2023]
Abstract
Ionic liquids (ILs) are organic salts with low melting point that are being considered as green replacements for industrial volatile organic compounds. The reputation of these solvents as "environmental friendly" chemicals is based primarily on their negligible vapor pressure. Nonetheless, the solubility of ILs in water and a number of literature documenting toxicity of ILs to aquatic organisms highlight a real cause for concern. The knowledge of ILs behavior in the terrestrial environment, which includes microbial degradation, sorption and desorption, is equally important since both soil and aquatic milieu are possible recipients of IL contamination. This article reviews the achievements and current status of environmental risk assessment of ILs, and hopefully provides insights into this research frontier.
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Affiliation(s)
- Thi Phuong Thuy Pham
- Department of Bioprocess Engineering, Chonbuk National University, Jeonju, Chonbuk 561-756, Republic of Korea
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22
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Elsayed MMA, Vierl U, Cevc G. Accurate potentiometric determination of lipid membrane-water partition coefficients and apparent dissociation constants of ionizable drugs: electrostatic corrections. Pharm Res 2009; 26:1332-43. [PMID: 19283456 DOI: 10.1007/s11095-009-9842-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 01/26/2009] [Indexed: 11/25/2022]
Abstract
PURPOSE Potentiometric lipid membrane-water partition coefficient studies neglect electrostatic interactions to date; this leads to incorrect results. We herein show how to account properly for such interactions in potentiometric data analysis. MATERIALS AND METHODS We conducted potentiometric titration experiments to determine lipid membrane-water partition coefficients of four illustrative drugs, bupivacaine, diclofenac, ketoprofen and terbinafine. We then analyzed the results conventionally and with an improved analytical approach that considers Coulombic electrostatic interactions. RESULTS The new analytical approach delivers robust partition coefficient values. In contrast, the conventional data analysis yields apparent partition coefficients of the ionized drug forms that depend on experimental conditions (mainly the lipid-drug ratio and the bulk ionic strength). This is due to changing electrostatic effects originating either from bound drug and/or lipid charges. A membrane comprising 10 mol-% mono-charged molecules in a 150 mM (monovalent) electrolyte solution yields results that differ by a factor of 4 from uncharged membranes results. CONCLUSION Allowance for the Coulombic electrostatic interactions is a prerequisite for accurate and reliable determination of lipid membrane-water partition coefficients of ionizable drugs from potentiometric titration data. The same conclusion applies to all analytical methods involving drug binding to a surface.
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Lombardo F, Faller B, Shalaeva M, Tetko I, Tilton S. The Good, the Bad and the Ugly of Distribution Coefficients: Current Status, Views and Outlook. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/9783527621286.ch16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Wang Y, Chow MS, Zuo Z. Mechanistic analysis of pH-dependent solubility and trans-membrane permeability of amphoteric compounds: Application to sildenafil. Int J Pharm 2008; 352:217-24. [DOI: 10.1016/j.ijpharm.2007.10.039] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 10/26/2007] [Accepted: 10/28/2007] [Indexed: 10/22/2022]
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25
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Tejwani RW, Anderson BD. Influence of Intravesicular pH Drift and Membrane Binding on the Liposomal Release of a Model Amine‐Containing Permeant. J Pharm Sci 2008; 97:381-99. [PMID: 17694543 DOI: 10.1002/jps.21108] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Accurate determination of intrinsic permeability coefficients is critical to the development of structure-permeability relationships and liposomal delivery systems. The apparent release rate of a drug from liposomes may reflect not only its intrinsic permeability coefficient and barrier properties but also a variety of underlying equilibria including drug ionization, membrane binding or complexation, and kinetic processes such as buffer exchange. Additionally, transport of ionizable drugs that are initially at high concentrations in liposomes can generate or dissipate pH gradients across the barrier causing deviations from classical pH-permeability profiles. In this study, the liposomal release of a model amine (tyramine) is determined as a function of drug loading, intravesicular pH, and buffer composition. Kinetic models are derived to study effects of such equilibria (e.g., ionization, membrane binding) and kinetic processes (e.g., pH drift and acid/base carriers). All equilibrium constants needed for the models were independently measured and used. The barrier properties of the lipid bilayers under the experimental conditions were assessed by monitoring the transport of mannitol and bretylium as a function of pH. A corrected intrinsic permeability coefficient of 0.04 cm/s was in close agreement with the value predicted from the barrier domain model for bilayer permeability, suggesting that all perturbing factors were properly addressed.
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Affiliation(s)
- Ravindra W Tejwani
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40506, USA
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26
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Fischer H, Kansy M, Avdeef A, Senner F. Permeation of permanently positive charged molecules through artificial membranes--influence of physico-chemical properties. Eur J Pharm Sci 2007; 31:32-42. [PMID: 17416489 DOI: 10.1016/j.ejps.2007.02.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 02/05/2007] [Accepted: 02/05/2007] [Indexed: 11/26/2022]
Abstract
The aim of this study was to investigate the permeation properties of 20 permanently positive charged molecules in the parallel artificial membrane permeability assay (PAMPA). Eight of them were derivatives of the N-alkyl-isoquinolinium salt and 12 were congeners of the dye rhodamine 110. Five out of 12 molecules from the rhodamine 110 series have one additional carboxylic group and two have two carboxylic acids. The experimentally derived effective permeability values (P(e)) cover a range of 3-4 log units. Ten compounds showed low permeabilities (P(e)<0.1x10(-6)cm/s), four medium permeabilities (0.1x10(-6)< or =P(e)<1x10(-6)cm/s) and six were highly permeable (P(e)> or =1x10(-6)cm/s). In addition, computational models were built with a number of calculated molecular descriptors and evaluated for their ability to predict membrane permeability. It turned out that the experimental P(e) values can be explained by electronic properties and parameters describing the shape of molecules. This work provides evidence that permanently charged molecules can have high passive membrane permeabilities provided that the charge can be spread over several aromatic ring systems.
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Affiliation(s)
- Holger Fischer
- Pharmaceutical Research, Discovery Chemistry-Molecular Properties, F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland.
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27
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Murnane D, Martin GP, Marriott C. Validation of a reverse-phase high performance liquid chromatographic method for concurrent assay of a weak base (salmeterol xinafoate) and a pharmacologically active steroid (fluticasone propionate). J Pharm Biomed Anal 2005; 40:1149-54. [PMID: 16280225 DOI: 10.1016/j.jpba.2005.09.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Revised: 09/16/2005] [Accepted: 09/23/2005] [Indexed: 11/30/2022]
Abstract
The analysis of weakly basic drugs such as salmeterol xinafoate (SX) by reverse-phase liquid chromatography remains a problem, particularly when present in combination with other drugs such as steroids and weak acids. This study describes the validation of an assay for a weakly basic drug, salmeterol (SB), its weakly acidic counter-ion, 1-hydroxy-2-naphthoic acid (XA), and the neutral glucocorticoid, fluticasone propionate (FP) using a second-generation silica stationary phase (Inertsil ODS-2). The assay utilized an Inertsil ODS-2 base-deactivated 250 mm x 4.6mm, 5 microm HPLC column, with 75:25 methanol:0.6% aqueous ammonium acetate as the mobile phase. Under these near neutral conditions, SB demonstrated a good peak shape (tailing factor=1.21+/-0.02, n=85). The method provided a short analysis time: XA, t(R)=2.96 min; SB, t(R)=5.23 min and FP, t(R)=7.01 min. The assay displayed good sensitivity for both XA (LOD for SX=0.22 microgmL(-1)) and SB (LOD for SX=0.26 microgmL(-1)). The limit of detection for FP was 0.19 microgmL(-1). Neither of the drugs was found to interfere in the determination of the other and the assay accuracy (% recovery) was high (the recoveries were: 99.58+/-1.85% for XA, 99.49+/-1.88% for SB and 100.24+/-1.28% for FP). The assay reproducibility was determined with a mean coefficient of variance for the five calibration concentrations of XA=0.71+/-0.18%; SB=1.11+/-0.64% and FP=0.92+/-0.14%. Analysis of a pressurized metered dose inhaler formulation demonstrated recovery of the analytes that are within pharmacopoeial limits. It was shown that RP-HPLC was suitable for the high throughput analysis of the combination of SX and FP.
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Affiliation(s)
- D Murnane
- Drug Delivery Research Group, Pharmaceutical Science Research Division, King's College London, Stamford Street, London SE1 9NH, UK
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28
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Austin RP, Barton P, Davis AM, Fessey RE, Wenlock MC. The Thermodynamics of the Partitioning of Ionizing Molecules Between Aqueous Buffers and Phospholipid Membranes. Pharm Res 2005; 22:1649-57. [PMID: 16180122 DOI: 10.1007/s11095-005-6336-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2004] [Accepted: 06/06/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE To study the thermodynamics of partitioning of eight ionising dual D2-recepto beta2-adrenoceptor agonists between vesicles of L-alpha-dimyristoylphosphatidylcholine (DMPC) and aqueous buffers. METHODS The thermodynamics of partitioning have been studied by isothermal titration calorimetry (ITC). RESULTS Compounds which are predominantly cationic at pH 7.4 (designated as class 1 compounds) have a more exothermic partitioning than those which are predominantly in the electronically neutral form (designated as class 2 compounds) at pH 7.4, and less positive standard entropies of partitioning. Under acidic conditions (pH 4.0), class compounds 2 (predominantly electronically neutral at pH 7.4) are almost completely cationic and accordingly have a more exothermic partitioning than at pH 7.4. The standard entropies of partitioning also depend on the pH. When the compounds are predominantly cationic, the standard entropy change is less positive (less favourable) than under conditions where the compounds are predominantly electronically neutral. CONCLUSIONS The observations are consistent with the notion of there being a favourable electrostatic interaction (enthalpically) between the positively charged amino-group of predominantly cationic compounds and the negatively charged phosphate group of the vesicle.
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Affiliation(s)
- Rupert P Austin
- Department of Physical and Metabolic Sciences, AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire, LE11 5RH, UK
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29
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Thomae AV, Wunderli-Allenspach H, Krämer SD. Permeation of aromatic carboxylic acids across lipid bilayers: the pH-partition hypothesis revisited. Biophys J 2005; 89:1802-11. [PMID: 15951388 PMCID: PMC1366683 DOI: 10.1529/biophysj.105.060871] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
According to the pH-partition hypothesis the charged species of organic compounds do not contribute to lipid bilayer permeation as they generally show negligible partitioning into n-octanol. With this assumption, membrane permeation is related to the molar fraction of the neutral species at a particular pH. A recently developed permeation assay permits us to directly determine pH-dependent permeation of aromatic carboxylic acids. Tb(3+)-loaded liposomes are incubated with aromatic carboxylic acids and upon excitation at the absorption wavelength of the acid, permeation kinetics can be measured as an increase in Tb(3+) luminescence. The anions of the tested acids permeated egg phosphatidylcholine membranes only 12 (2-hydroxynicotinic acid), 66 (salicylic acid), and 155 (dipicolinic acid) times slower than the net neutral species. The anions, therefore, controlled the total permeation already at 1-2 pH units above their pK(a). These results indicate that in contrast to the expectations of the pH-partition hypothesis, lipid bilayer permeation of an acidic compound can be completely controlled by the anion at physiological pH.
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Affiliation(s)
- Anita V Thomae
- Department of Chemistry and Applied Biosciences, ETH Federal Institute of Technology, 8093 Zurich, Switzerland
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30
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Ranke J, Mölter K, Stock F, Bottin-Weber U, Poczobutt J, Hoffmann J, Ondruschka B, Filser J, Jastorff B. Biological effects of imidazolium ionic liquids with varying chain lengths in acute Vibrio fischeri and WST-1 cell viability assays. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2004; 58:396-404. [PMID: 15223265 DOI: 10.1016/s0147-6513(03)00105-2] [Citation(s) in RCA: 366] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2002] [Revised: 06/17/2003] [Accepted: 06/20/2003] [Indexed: 05/24/2023]
Abstract
Detailed biological studies of methyl- and some ethylimidazolium ionic liquids in luminescent bacteria as well as in the IPC-81 (leukemia cells) and C6 (glioma cells) rat cell lines are presented. Effective concentrations in these test systems are generally some orders of magnitude lower than effective concentrations [corrected] of the conventional solvents acetone, acetonitrile, methanol, and methyl t-butyl ether. No general influence of the anionic compound in the ionic liquids on toxicity could be found, although they seem to modulate toxicity in some cases. The clear influence of the alkyl chain length on toxicity was quantified by linear regression analysis. Alkyl chain length of the longer alkyl chain was varied from 3 to 10 carbon atoms. Consequences for a design of sustainable alternative solvents are briefly sketched.
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Affiliation(s)
- J Ranke
- UFT Center for Environmental Research and Environmental Technology, Leobenerstrasse, D-28359 Bremen, Germany.
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31
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Austin RP, Barton P, Bonnert RV, Brown RC, Cage PA, Cheshire DR, Davis AM, Dougall IG, Ince F, Pairaudeau G, Young A. QSAR and the rational design of long-acting dual D2-receptor/beta 2-adrenoceptor agonists. J Med Chem 2003; 46:3210-20. [PMID: 12852752 DOI: 10.1021/jm020886c] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper describes the development of a QSAR model for the rational control of functional duration of topical long-acting dual D(2)-receptor/beta(2)-adrenoceptor agonists for the treatment of chronic obstructive pulmonary disease. A QSAR model highlighted the importance of lipophilicity and ionization in controlling beta(2) duration. It was found that design rules logD(7.4) > 2, secondary amine pK(a) > 8.0, yielded ultra-long duration compounds. This model was used successfully to guide the design of long- and ultra-long-acting compounds. The QSAR model is discussed in terms of the exosite model, and the plasmalemma diffusion microkinetic hypothesis, for the control of beta(2) duration. Data presented strongly suggests that beta(2) duration is primarily controlled by the membrane affinity of these compounds.
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Affiliation(s)
- Rupert P Austin
- AstraZeneca R&D Charnwood, Bakewell Road, Loughborough, Leicestershire, LE11 5RH, UK
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32
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van de Waterbeemd H. Physicochemical concepts in drug design. EXS 2003:243-57. [PMID: 12613180 DOI: 10.1007/978-3-0348-7997-2_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Sugawara M, Kurosawa M, Sakai K, Kobayashi M, Iseki K, Miyazaki K. Ionic strength has a greater effect than does transmembrane electric potential difference on permeation of tryptamine and indoleacetic acid across Caco-2 cells. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1564:149-55. [PMID: 12101007 DOI: 10.1016/s0005-2736(02)00442-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effects of transmembrane electric potential difference and ionic strength on the permeation of tryptamine and indoleacetic acid across a Caco-2 cell monolayer were examined. A decrease in the transmembrane electric potential difference caused by the addition of potassium ion to the transport buffer had no effect on the permeation rate of either compound. On the other hand, an increase in ionic strength resulted in a decrease in the permeation rate of tryptamine and an increase in the permeation rate of indoleacetic acid. The changes in the permeation rate with changes in the ionic strength were correlated with the membrane surface potential monitored by 1-anilino-8-naphthalenesulfonic acid (ANS), a fluorescent probe. We tested these effects using several other cationic and anionic compounds. These effects of ionic strength were found to be common to all drugs tested. The compound that showed a relatively lower permeation rate was given relatively stronger effect. The possibility of overestimation or underestimation caused by these effects should be considered when the permeation of an ionic compound is evaluated using a cell monolayer system.
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Affiliation(s)
- Mitsuru Sugawara
- Department of Pharmacy, Hokkaido University Hospital, School of Medicine, Hokkaido University, Sapporo, Japan
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Gordon DJ, Tappe R, Meredith SC. Design and characterization of a membrane permeable N-methyl amino acid-containing peptide that inhibits Abeta1-40 fibrillogenesis. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2002; 60:37-55. [PMID: 12081625 DOI: 10.1034/j.1399-3011.2002.11002.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Alzheimer's disease, Huntington's disease and prion diseases are part of a growing list of diseases associated with formation of beta-sheet containing fibrils. In a previous publication, we demonstrated that the self-association of the Alzheimer's beta-amyloid (Abeta) peptide is inhibited by peptides homologous to the central core domain of Abeta, but containing N-methyl amino acids at alternate positions. When these inhibitor peptides are arrayed in an extended, beta-strand conformation, the alternating position of N-methyl amino acids gives the peptide two distinct faces, one exhibiting a normal pattern of peptide backbone hydrogen bonds, but the other face having limited hydrogen-bonding capabilities due to the replacement of the amide protons by N-methyl groups. Here, we demonstrate, through two-dimensional NMR and circular dichroic spectroscopy, that a pentapeptide with two N-methyl amino acids, Abeta16-20m or Ac-K(Me)LV(Me)FF-NH2, does indeed have the intended structure of an extended beta-strand. This structure is remarkably stable to changes in solvent conditions and resists denaturation by heating, changes in pH (from 2.5 to 10.5), and addition of denaturants such as urea and guanindine-HCl. We also show that this peptide, despite its hydrophobic composition, is highly water soluble, to concentrations > 30 mm, in contrast to the nonmethylated congener, Abeta16-20 (Ac-KLVFF-NH2). The striking water solubility, in combination with the hydrophobic composition of the peptide, suggested that the peptide might be able to pass spontaneously through cell membranes and model phospholipid bilayers such as unilamellar vesicles. Thus, we also demonstrate that this peptide is indeed able to pass spontaneously through both synthetic phospholipid bilayer vesicles and cell membranes. Characterization of the biophysical properties of the Abeta16-20m peptide may facilitate the application of this strategy to other systems as diverse as the HIV protease and chemokines, in which there is dimerization through beta-strand domains.
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Affiliation(s)
- D J Gordon
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA
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35
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Osterberg T, Svensson M, Lundahl P. Chromatographic retention of drug molecules on immobilised liposomes prepared from egg phospholipids and from chemically pure phospholipids. Eur J Pharm Sci 2001; 12:427-39. [PMID: 11231109 DOI: 10.1016/s0928-0987(00)00183-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The partitioning of a chemically diverse set of drugs into liposomes was studied by immobilised liposome chromatography (ILC). For this purpose liposomes composed of (i) purified egg phospholipids (EPL), (ii) synthetic phosphatidylcholine (PC), (iii) PC--synthetic phosphatidylethanolamine (PE) 80:20 (mol/mol) and (iv) PC--synthetic phosphatidylserine (PS) 80:20 (mol/mol) were immobilised in gel beads by freeze-thawing. The drug partitioning was assessed from the retention volume, which was expressed as a capacity factor, K(s), normalised with respect to the amount of immobilised phospholipid. The drug retention on EPL, PC and PC--PE liposomes was very similar, whereas the negatively charged PC--PS liposomes increased the retention of positively charged and decreased retention of negatively charged drugs. The partitioning of drugs on liposome columns (log K(s)) versus their octanol--water partitioning (log P(oct)) showed three separate rectilinear relationships, depending on the charge of the compound (neutral, positive, or negative). Statistical analysis (ANCOVA) proved that the lines had similar slopes. Repeated analysis of four reference compounds showed a low variation (<0.12 log units) over time (about 250 days). A close relationship was observed between the drug retention in short EPL columns with a low content of phospholipids and the retention in longer standard EPL columns. The short 'quick screen bilayer columns' permit analysis of highly lipophilic compounds within 30 min and are thus applicable for medium-throughput screening in drug discovery settings. A very strong rectilinear relationship (r(2)=0.95, n=13) between log K(s) (EPL) and published liposome partitioning data (log D(mem)) confirmed that the ILC drug retention reflects the drug partitioning into the lipid bilayers. A moderate to fair rectilinear relationship was observed between the normalised retention on PC, PC-PE and EPL liposomes (r(2)=0.79, 0.86 and 0.85, respectively, n=24) and corresponding published log k'(IAM) data obtained on immobilised artificial membrane (IAM) columns. Transport across Caco-2 cell monolayers (log P(c)) showed curvilinear relationships with log K(s), log k'(IAM), log P(oct) and log D(oct). The drug fraction absorbed in humans showed a similar relationship to log K(s) values as to surface plasmon resonance signals representing drug-liposome interaction (Danelian et al., 2000 J Med Chem, 43, 2083--2086).
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Affiliation(s)
- T Osterberg
- AstraZeneca R&D Södertälje, SE-151 85 Södertälje, Sweden.
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36
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Michael Y, Chowdhry BZ, Ashurst IC, Snowden MJ, Davies-Cutting C, Gray S. The physico-chemical properties of salmeterol and fluticasone propionate in different solvent environments. Int J Pharm 2000; 200:279-88. [PMID: 10867258 DOI: 10.1016/s0378-5173(00)00397-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The physico-chemical properties of two anti-asthmatic drugs, salmeterol xinafoate and fluticasone propionate, have been studied in both aqueous and non-aqueous solvent environments. Ultraviolet-visible (UV-Vis) spectroscopy, fluorescence spectroscopy and electrospray ionisation mass spectrometry (ESI-MS) have been used to characterise the interaction of the drugs in 70:30 (v/v) methanol/water solutions. First derivative UV-Vis spectra measurements indicate that an interaction takes place between the two drugs in a binary solvent system. Fluorescence studies indicate that an increase in the concentration of fluticasone propionate results in a decrease in the fluorescence signal of the salmeterol for mixed solutions of the drugs. Analysis of a mixture of the two drug solutions using mass spectrometry also shows evidence of salmeterol-fluticasone propionate interaction and dimer formation with respect to both the salmeterol and the fluticasone propionate. Model metered dose inhalers (MDI) of both individual samples and mixtures of the drugs were formulated as suspensions in solvent CFC-113. The extent of deposition onto different inhaler components, such as the aluminium alloy canister, Teflon coated canister and the metering valve was evaluated by high-performance liquid chromatography (HPLC) of the methanol/water washings of the deposited drug(s). Changing the nature of the surface properties of the container resulted in a significant difference in the extent of deposition. The deposition of the individual drugs was found to increase as the dispersion concentration of the drug increases. However, the formulation based on a combination of the two drugs was found to show different deposition behaviour compared to the individual drug formulations. The deposition of the drugs, onto the aluminium alloy canister and the metering valve, decreases as the combined dispersion concentration of the two drug increases.
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Affiliation(s)
- Y Michael
- School of Chemical and Life Sciences, University of Greenwich, Wellington Street, Woolwich, SE18 6PF, London, UK
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