1
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Pires CL, Moreno MJ. Improving the Accuracy of Permeability Data to Gain Predictive Power: Assessing Sources of Variability in Assays Using Cell Monolayers. MEMBRANES 2024; 14:157. [PMID: 39057665 PMCID: PMC11278619 DOI: 10.3390/membranes14070157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/05/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024]
Abstract
The ability to predict the rate of permeation of new compounds across biological membranes is of high importance for their success as drugs, as it determines their efficacy, pharmacokinetics, and safety profile. In vitro permeability assays using Caco-2 monolayers are commonly employed to assess permeability across the intestinal epithelium, with an extensive number of apparent permeability coefficient (Papp) values available in the literature and a significant fraction collected in databases. The compilation of these Papp values for large datasets allows for the application of artificial intelligence tools for establishing quantitative structure-permeability relationships (QSPRs) to predict the permeability of new compounds from their structural properties. One of the main challenges that hinders the development of accurate predictions is the existence of multiple Papp values for the same compound, mostly caused by differences in the experimental protocols employed. This review addresses the magnitude of the variability within and between laboratories to interpret its impact on QSPR modelling, systematically and quantitatively assessing the most common sources of variability. This review emphasizes the importance of compiling consistent Papp data and suggests strategies that may be used to obtain such data, contributing to the establishment of robust QSPRs with enhanced predictive power.
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Affiliation(s)
- Cristiana L. Pires
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
- Chemistry Department, Faculty of Science and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Maria João Moreno
- Coimbra Chemistry Center—Institute of Molecular Sciences (CQC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
- Chemistry Department, Faculty of Science and Technology, University of Coimbra, 3004-535 Coimbra, Portugal
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2
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Möbitz H. Design Principles for Balancing Lipophilicity and Permeability in beyond Rule of 5 Space. ChemMedChem 2024; 19:e202300395. [PMID: 37986275 DOI: 10.1002/cmdc.202300395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/13/2023] [Accepted: 11/16/2023] [Indexed: 11/22/2023]
Abstract
An ab initio conformational analysis of oral beyond Rule of 5 (bRo5) drugs was complemented with measured permeability and logP(octanol) to derive design principles conferring oral bioavailability. 3D polar surface area (PSA) thresholds for oral bRo5 drugs coincided with those reported for Ro5 space. The majority of oral bRo5 drugs exceeded the Ro5 logP threshold of 5, reflecting a bias for permeability. Above 500 Da molecular weight (MW), oral drugs and highly permeable Novartis compounds occupy a narrow polarity range (topological or TPSA/MW) of 0.1-0.3 Å2 /Da, whose upper half coincides with the lower 90 percentiles of the Novartis logP set. This TPSA/MW range and 3D PSA below 100 Å2 define the "Rule of ~1 /₅" for balancing lipophilicity and permeability. Neutral TPSA, defined as TPSA minus 3D PSA occurs independent of conformation, intramolecular hydrogen bonds (IMHB) and MW, suggesting it is an intrinsic molecular property. Neutral TPSA increased in the lead optimization (LO) campaigns of three first in class de novo designed bRo5 drugs and may be a useful design parameter in bRo5 space.
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Affiliation(s)
- Henrik Möbitz
- Computer-Aided Drug Design, Global Discovery Chemistry, Novartis BioMedical Research, 4002, Basel, Switzerland
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3
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Wang Z, Felstead HR, Troup RI, Linclau B, Williamson PTF. Lipophilicity Modulations by Fluorination Correlate with Membrane Partitioning. Angew Chem Int Ed Engl 2023; 62:e202301077. [PMID: 36932824 PMCID: PMC10946813 DOI: 10.1002/anie.202301077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 03/19/2023]
Abstract
Bioactive compounds generally need to cross membranes to arrive at their site of action. The octanol-water partition coefficient (lipophilicity, logPOW ) has proven to be an excellent proxy for membrane permeability. In modern drug discovery, logPOW and bioactivity are optimized simultaneously, for which fluorination is one of the relevant strategies. The question arises as to which extent the often subtle logP modifications resulting from different aliphatic fluorine-motif introductions also lead to concomitant membrane permeability changes, given the difference in molecular environment between octanol and (anisotropic) membranes. It was found that for a given compound class, there is excellent correlation between logPOW values with the corresponding membrane molar partitioning coefficients (logKp ); a study enabled by novel solid-state 19 F NMR MAS methodology using lipid vesicles. Our results show that the factors that cause modulation of octanol-water partition coefficients similarly affect membrane permeability.
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Affiliation(s)
- Zhong Wang
- School of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Hannah R. Felstead
- School of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Robert I. Troup
- School of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
| | - Bruno Linclau
- School of ChemistryUniversity of Southampton HighfieldSouthamptonSO17 1BJUK
- Department of Organic and Macromolecular ChemistryGhent University Campus SterreKrijgslaan 281-S49000GhentBelgium
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4
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Nguyen NPK, Tran KN, Nguyen LTH, Shin HM, Yang IJ. Effects of Essential Oils and Fragrant Compounds on Appetite: A Systematic Review. Int J Mol Sci 2023; 24:ijms24097962. [PMID: 37175666 PMCID: PMC10178777 DOI: 10.3390/ijms24097962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 04/21/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Appetite dysregulation is one of the factors contributing to anorexia, bulimia nervosa, obesity, and diabetes. Essential oils or fragrant compounds have been proven to regulate food intake and energy expenditure; hence, this study aimed to summarize their effects on appetite and the underlying mechanisms. The PubMed and Web of Science databases were searched until July 2022. Only two of the 41 studies were performed clinically, and the remaining 39 used animal models. Oral administration was the most common route, and a dosage range of 100-2000 mg/kg for mice or 2-32 mg/kg for rats was applied, with a duration of 12 days to 4 weeks, followed by inhalation (10-6-10-3 mg/cage or 10-9-10-2 mg/cm3 within 1 h). Approximately 11 essential oil samples and 22 fragrant compounds were found to increase appetite, while 12 essential oils and seven compounds decreased appetite. These fragrant components can exert appetite-regulating effects via leptin resistance, the activity of sympathetic/parasympathetic nerves, or the mRNA expression of neuropeptide Y (NPY)/agouti-related protein (AgRP), cocaine- and amphetamine-regulated transcript (CART)/proopiomelanocortin (POMC) in the hypothalamus. Fragrance memory and cognitive processes may also play roles in appetite regulation. The findings of this study accentuate the potential of essential oils and fragrant compounds to regulate appetite and eating disorders.
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Affiliation(s)
- Nhi Phuc Khanh Nguyen
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
| | - Khoa Nguyen Tran
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
| | - Ly Thi Huong Nguyen
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
| | - Heung-Mook Shin
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
| | - In-Jun Yang
- Department of Physiology, College of Korean Medicine, Dongguk University, Gyeongju 38066, Republic of Korea
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5
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Kafkova A, Tilokani L, Trčka F, Šrámková V, Vancová M, Bílý T, Nebesářová J, Prudent J, Trnka J. Selective and reversible disruption of mitochondrial inner membrane protein complexes by lipophilic cations. Mitochondrion 2023; 68:60-71. [PMID: 36402364 DOI: 10.1016/j.mito.2022.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 11/11/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022]
Abstract
Triphenylphosphonium (TPP) derivatives are commonly used to target chemical into mitochondria. We show that alkyl-TPP cause reversible, dose- and hydrophobicity-dependent alterations of mitochondrial morphology and function and a selective decrease of mitochondrial inner membrane proteins including subunits of the respiratory chain complexes, as well as components of the mitochondrial calcium uniporter complex. The treatment with alkyl-TPP resulted in the cleavage of the pro-fusion and cristae organisation regulator Optic atrophy-1. The structural and functional effects of alkyl-TPP were found to be reversible and not merely due to loss of membrane potential. A similar effect was observed with the mitochondria-targeted antioxidant MitoQ.
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Affiliation(s)
- Anezka Kafkova
- Laboratory for Metabolism and Bioenergetics, Department of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Czech Republic
| | - Lisa Tilokani
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Filip Trčka
- Laboratory for Metabolism and Bioenergetics, Department of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Czech Republic
| | - Veronika Šrámková
- Department of Pathophysiology, Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marie Vancová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Tomáš Bílý
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Jana Nebesářová
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Ceske Budejovice, Czech Republic; Laboratory of Electron Microscopy, Faculty of Science, Charles University, Prague, Czech Republic
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Jan Trnka
- Laboratory for Metabolism and Bioenergetics, Department of Biochemistry, Cell and Molecular Biology, Third Faculty of Medicine, Charles University, Czech Republic.
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6
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Erckes V, Steuer C. A story of peptides, lipophilicity and chromatography - back and forth in time. RSC Med Chem 2022; 13:676-687. [PMID: 35800203 PMCID: PMC9215158 DOI: 10.1039/d2md00027j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/18/2022] [Indexed: 11/25/2022] Open
Abstract
Peptides, as part of the beyond the rule of 5 (bRo5) chemical space, represent a unique class of pharmaceutical compounds. Because of their exceptional position in the chemical space between traditional small molecules (molecular weight (MW) < 500 Da) and large therapeutic proteins (MW > 5000 Da), peptides became promising candidates for targeting challenging binding sites, including even targets traditionally considered as undruggable - e.g. intracellular protein-protein interactions. However, basic knowledge about physicochemical properties that are important for a drug to be membrane permeable is missing but would enhance the drug discovery process of bRo5 molecules. Consequently, there is a demand for quick and simple lipophilicity determination methods for peptides. In comparison to the traditional lipophilicity determination methods via shake flask and in silico prediction, chromatography-based methods could have multiple benefits such as the requirement of low analyte amount, insensitivity to impurities and high throughput. Herein we elucidate the role of peptide lipophilicity and different lipophilicity values. Further, we summarize peptide analysis via common chromatographic techniques, in specific reversed phase liquid chromatography, hydrophilic interaction liquid chromatography and supercritical fluid chromatography and their role in drug discovery and development process.
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Affiliation(s)
- Vanessa Erckes
- Pharmaceutical Analytics, Institute of Pharmaceutical Sciences, Federal Institute of Technology Zurich 8093 Zurich Switzerland
| | - Christian Steuer
- Pharmaceutical Analytics, Institute of Pharmaceutical Sciences, Federal Institute of Technology Zurich 8093 Zurich Switzerland
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7
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Rokitskaya TI, Aleksandrova EV, Korshunova GA, Khailova LS, Tashlitsky VN, Luzhkov VB, Antonenko YN. Membrane Permeability of Modified Butyltriphenylphosphonium Cations. J Phys Chem B 2022; 126:412-422. [PMID: 34994564 DOI: 10.1021/acs.jpcb.1c08135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The alkyltriphenylphosphonium (TPP) group is the most widely used vector targeted to mitochondria. Previously, the length of the alkyl linker was varied as well as structural modifications in the TPP phenyl rings to obtain the optimal therapeutic effect of a pharmacophore conjugated with a lipophilic cation. In the present work, we synthesized butyltriphenylphosphonium cations halogenated and methylated in phenyl rings (C4TPP-X) and measured electrical current through a planar lipid bilayer in the presence of C4TPP-X. The permeability of C4TPP-X varied in the range of 6 orders of magnitude and correlates well with the previously measured translocation rate constant for dodecyltriphenylphosphonium analogues. The partition coefficient of the butyltriphenylphosphonium analogues obtained by calculating the difference in the free energy of cation solvation in water and octane using quantum chemical methods correlates well with the permeability values. Using an ion-selective electrode, a lower degree of accumulation of analogues with halogenated phenyl groups was found on isolated mitochondria of rat liver, which is in agreement with their permeability decrease. Our results indicate the translocation of the butyltriphenylphosphonium cations across the hydrophobic membrane core as rate-limiting stage in the permeability process rather than their binding/release to/from the membrane.
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Affiliation(s)
- Tatyana I Rokitskaya
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | | | - Galina A Korshunova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ljudmila S Khailova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Vadim N Tashlitsky
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Victor B Luzhkov
- Department of Kinetics of Chemical and Biological Processes, Institute of Problems of Chemical Physics, Russian Academy of Sciences, acad. Semenov av. 1, Chernogolovka, Moscow Region 142432, Russia.,Department of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Yuri N Antonenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow 119991, Russia
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8
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Sharifian Gh M. Recent Experimental Developments in Studying Passive Membrane Transport of Drug Molecules. Mol Pharm 2021; 18:2122-2141. [PMID: 33914545 DOI: 10.1021/acs.molpharmaceut.1c00009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The ability to measure the passive membrane permeation of drug-like molecules is of fundamental biological and pharmaceutical importance. Of significance, passive diffusion across the cellular membranes plays an effective role in the delivery of many pharmaceutical agents to intracellular targets. Hence, approaches for quantitative measurement of membrane permeability have been the topics of research for decades, resulting in sophisticated biomimetic systems coupled with advanced techniques. In this review, recent developments in experimental approaches along with theoretical models for quantitative and real-time analysis of membrane transport of drug-like molecules through mimetic and living cell membranes are discussed. The focus is on time-resolved fluorescence-based, surface plasmon resonance, and second-harmonic light scattering approaches. The current understanding of how properties of the membrane and permeant affect the permeation process is discussed.
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Affiliation(s)
- Mohammad Sharifian Gh
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia 22908, United States
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9
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Arena ME, Alberto MR, Cartagena E. Potential use of Citrus essential oils against acute respiratory syndrome caused by coronavirus. JOURNAL OF ESSENTIAL OIL RESEARCH 2021. [DOI: 10.1080/10412905.2021.1912839] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Mario Eduardo Arena
- Instituto de Biotecnología Farmacéutica y Alimentaria (INBIOFAL) CONICET–UNT, Tucumán, Argentina
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Tucumán, Argentina
| | - María Rosa Alberto
- Instituto de Biotecnología Farmacéutica y Alimentaria (INBIOFAL) CONICET–UNT, Tucumán, Argentina
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Tucumán, Argentina
| | - Elena Cartagena
- Instituto de Biotecnología Farmacéutica y Alimentaria (INBIOFAL) CONICET–UNT, Tucumán, Argentina
- Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán (UNT), Tucumán, Argentina
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10
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Bachler S, Ort M, Krämer SD, Dittrich PS. Permeation Studies across Symmetric and Asymmetric Membranes in Microdroplet Arrays. Anal Chem 2021; 93:5137-5144. [PMID: 33721989 PMCID: PMC8014892 DOI: 10.1021/acs.analchem.0c04939] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We investigated the permeation of molecules across lipid membranes on an open microfluidic platform. An array of droplet pairs was created by spotting aqueous droplets, dispersed in a lipid oil solution, onto a plate with cavities surrounded by a hydrophobic substrate. Droplets in two adjacent cavities come in contact and form an artificial lipid bilayer, called a droplet interface bilayer (DIB). The method allows for monitoring permeation of fluorescently tagged compounds from a donor droplet to an acceptor droplet. A mathematical model was applied to describe the kinetics and determine the permeation coefficient. We also demonstrate that permeation kinetics can be followed over a series of droplets, all connected via DIBs. Moreover, by changing the lipid oil composition after spotting donor droplets, we were able to create asymmetric membranes that we used to mimic the asymmetry of the cellular plasma membrane. Finally, we developed a protocol to separate and extract the droplets for label-free analysis of permeating compounds by liquid chromatography-mass spectrometry. Our versatile platform has the potential to become a new tool for the screening of drug membrane permeability in the future.
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Affiliation(s)
- Simon Bachler
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
| | - Marion Ort
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
| | - Stefanie D Krämer
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, ETH Zurich, Zürich 8093, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, ETH Zurich, 4058 Basel, Switzerland
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11
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Colalto C. Volatile molecules for COVID-19: A possible pharmacological strategy? Drug Dev Res 2020; 81:950-968. [PMID: 32779824 PMCID: PMC7404447 DOI: 10.1002/ddr.21716] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/01/2020] [Accepted: 06/24/2020] [Indexed: 12/27/2022]
Abstract
COVID-19 is a novel coronavirus disease with a higher incidence of bilateral pneumonia and pleural effusion. The high pulmonary tropism and contagiousness of the virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have stimulated new approaches to combat its widespread diffusion. In developing new pharmacological strategies, the chemical characteristic of volatility can add therapeutic value to the hypothetical drug candidate. Volatile molecules are characterized by a high vapor pressure and are consequently easily exhaled by the lungs after ingestion. This feature could be exploited from a pharmacological point of view, reaching the site of action in an uncommon way but allowing for drug delivery. In this way, a hypothetical molecule for COVID-19 should have a balance between its lung exhalation characteristics and both antiviral and anti-inflammatory pharmacological action. Here, the feasibility, advantages, and disadvantages of a therapy based on oral administration of possible volatile drugs for COVID-19 will be discussed. Both aerosolized antiviral therapy and oral intake of volatile molecules are briefly reviewed, and an evaluation of 1,8-cineole is provided in view of a possible clinical use and also for asymptomatic COVID-19.
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Affiliation(s)
- Cristiano Colalto
- Working Group “Pharmacognosy, Phytotherapy and Nutraceuticals”Italian Pharmacological SocietyMilanItaly
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12
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Updating the portfolio of physicochemical descriptors related to permeability in the beyond the rule of 5 chemical space. Eur J Pharm Sci 2020; 146:105274. [PMID: 32088315 DOI: 10.1016/j.ejps.2020.105274] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 02/08/2023]
Abstract
Beyond rule of 5 (bRo5) molecules are attracting significant interest in modern drug discovery mostly because many novel targets require large and more flexible structures. The main aim of this paper is the identification of ad hoc bRo5 physicochemical descriptors of ionization, lipophilicity, polarity and chameleonicity and their measurement. We used different methods to collect ionization (pKa measures and log k'80 PLRP-S trends), lipophilicity (in octanol/water, in apolar systems and in biomimetic environments), polarity (Δlog Poct-tol, EPSA and Δlog KWIAM) and chameleonicity (ChameLogD) descriptors for 26 bRo5 drugs. A second aim was to check the relationship between physicochemical descriptors and permeability for a subset of compounds for which solid permeability values are reported in the literature. Results showed that the physicochemical profile in the bRo5 chemical space is often experimentally accessible, albeit more tools are required to overcome limitations of individual methods. For the investigated compounds, permeability is governed by Δlog Poct-tol and preliminary data support that chameleonicity could also have an impact.
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13
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Wielińska J, Nowacki A, Liberek B. 5-Fluorouracil-Complete Insight into Its Neutral and Ionised Forms. Molecules 2019; 24:molecules24203683. [PMID: 31614932 PMCID: PMC6832121 DOI: 10.3390/molecules24203683] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 10/06/2019] [Accepted: 10/11/2019] [Indexed: 11/16/2022] Open
Abstract
5-Fluorouracil (5FU), a common anti-cancer drug, occurs in four tautomeric forms and possesses two potential sites of both protonation and deprotonation. Tautomeric and resonance structures of the ionized forms of 5FU create the systems of connected equilibriums. Since there are contradictory reports on the ionized forms of 5FU in the literature, complex theoretical studies on neutral, protonated and deprotonated forms of 5FU, based on the broad spectrum of DFT methods, are presented. These indicate that the O4 oxygen is more willingly protonated than the O2 oxygen and the N1 nitrogen is more willingly deprotonated than the N3 nitrogen in a gas phase. Such preferences are due to advantageous charge delocalization of the respective ions, which is demonstrated by the NBO and ESP analyses. In an aqueous phase, stability differences between respective protonated and deprotonated forms of 5FU are significantly diminished due to the competition between the mesomeric effect and solvation. The calculated pKa values of the protonated, neutral and singly deprotonated 5FU indicate that 5FU does not exist in the protonated and double-deprotonated forms in the pH range of 0–14. The neutral form dominates below pH 8 and the N1 deprotonated form dominates above pH 8.
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Affiliation(s)
- Justyna Wielińska
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Andrzej Nowacki
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
| | - Beata Liberek
- Faculty of Chemistry, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland.
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14
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Ghanbari R, Assenza S, Zueblin P, Mezzenga R. Impact of Molecular Partitioning and Partial Equilibration on the Estimation of Diffusion Coefficients from Release Experiments. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5663-5671. [PMID: 30929450 DOI: 10.1021/acs.langmuir.9b00510] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The present work addresses the effect of partial equilibration and molecular partitioning on the interpretation of release experiments. In this regard, it is shown how release profiles and the values of extracted transport parameters are affected by the time protocol chosen for sample collection by considering a series of experiments where the latter is systematically varied. Caffeine is investigated as a main model drug because of its similar affinity for water and lipids, while monolinolein-based lipid cubic phases are chosen as host matrices because of their wide employment in release studies. Our findings point to a progressive decline in diffusion rate upon increasing the time step, that is, the gap in time between two consecutive pickups, which is a signature of increasing equilibration of caffeine concentration between the lipidic mesophase and the water phase. Furthermore, the amount of released molecules at the first pickup displays negligible changes for large time steps, indicating complete equilibration in such cases. A model is introduced based on Fick's diffusion which goes beyond the assumption of perfect-sink conditions, a common feature of the typical theoretical approaches hitherto developed. The model is shown to account quantitatively for the experimental data and is subsequently employed to clarify the interplay of the adopted release protocol with the various transport parameters in determining the final outcome of the release process. Particularly, two additional molecular drugs are considered, namely glucose and proflavine, which are, respectively, more hydrophilic and hydrophobic than caffeine, thus allowing elucidating the role of molecular partitioning.
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Affiliation(s)
- Reza Ghanbari
- Food and Soft Materials Science, Department of Health Science & Technology, Institute of Food, Nutrition & Health , ETH Zurich , Schmelzbergstrasse 9 , CH-8092 Zurich , Switzerland
| | - Salvatore Assenza
- Food and Soft Materials Science, Department of Health Science & Technology, Institute of Food, Nutrition & Health , ETH Zurich , Schmelzbergstrasse 9 , CH-8092 Zurich , Switzerland
| | - Patrick Zueblin
- Food and Soft Materials Science, Department of Health Science & Technology, Institute of Food, Nutrition & Health , ETH Zurich , Schmelzbergstrasse 9 , CH-8092 Zurich , Switzerland
| | - Raffaele Mezzenga
- Food and Soft Materials Science, Department of Health Science & Technology, Institute of Food, Nutrition & Health , ETH Zurich , Schmelzbergstrasse 9 , CH-8092 Zurich , Switzerland
- Department of Materials , ETH Zurich , Wolfgang-Pauli-Strasse 10 , 8093 Zurich , Switzerland
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15
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Dickson CJ, Hornak V, Bednarczyk D, Duca JS. Using Membrane Partitioning Simulations To Predict Permeability of Forty-Nine Drug-Like Molecules. J Chem Inf Model 2018; 59:236-244. [DOI: 10.1021/acs.jcim.8b00744] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Callum J. Dickson
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Viktor Hornak
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Dallas Bednarczyk
- PK Sciences, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jose S. Duca
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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16
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Stumpff F. A look at the smelly side of physiology: transport of short chain fatty acids. Pflugers Arch 2018; 470:571-598. [PMID: 29305650 DOI: 10.1007/s00424-017-2105-9] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
Fermentative organs such as the caecum, the colon, and the rumen have evolved to produce and absorb energy rich short chain fatty acids (SCFA) from otherwise indigestible substrates. Classical models postulate diffusional uptake of the undissociated acid (HSCFA). However, in net terms, a major part of SCFA absorption occurs with uptake of Na+ and resembles classical, coupled electroneutral NaCl transport. Considerable evidence suggests that the anion transporting proteins expressed by epithelia of fermentative organs are poorly selective and that their main function may be to transport acetate-, propionate-, butyrate- and HCO3- as the physiologically relevant anions. Apical uptake of SCFA thus involves non-saturable diffusion of the undissociated acid (HSCFA), SCFA-/HCO3- exchange via DRA (SLC26A3) and/or SCFA--H+ symport (MCT1, SLC16A1). All mechanisms lead to cytosolic acidification with stimulation of Na+/H+ exchange via NHE (SLC9A2/3). Basolaterally, Na+ leaves via the Na+/K+-ATPase with recirculation of K+. Na+ efflux drives the transport of SCFA- anions through volume-regulated anion channels, such as maxi-anion channels (possibly SLCO2A1), LRRC8, anoctamins, or uncoupled exchangers. When luminal buffering is inadequate, basolateral efflux will increasingly involve SCFA-/ HCO3- exchange (AE1/2, SCL4A1/2), or efflux of SCFA- with H+ (MCT1/4, SLC16A1/3). Furthermore, protons can be basolaterally removed by NHE1 (SCL9A1) or NBCe1 (SLC4A4). The purpose of these transport proteins is to maximize the amount of SCFA transported from the tightly buffered ingesta while minimizing acid transport through the epithelium. As known from the rumen for many decades, a disturbance of these processes is likely to cause severe colonic disease.
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Affiliation(s)
- Friederike Stumpff
- Institute of Veterinary Physiology, Department of Veterinary Medicine, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
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17
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The Flip-Flop Diffusion Mechanism across Lipids in a Hybrid Bilayer Membrane. Biophys J 2017; 110:2451-2462. [PMID: 27276263 DOI: 10.1016/j.bpj.2016.04.041] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/03/2016] [Accepted: 04/25/2016] [Indexed: 12/31/2022] Open
Abstract
In this study, we examine the mechanism of flip-flop diffusion of proton carriers across the lipid layer of a hybrid bilayer membrane (HBM). The HBM consists of a lipid monolayer appended on top of a self-assembled monolayer containing a Cu-based O2 reduction catalyst on a Au electrode. The flip-flop diffusion rates of the proton carriers dictate the kinetics of O2 reduction by the electrocatalyst. By varying both the tail lengths of the proton carriers and the lipids, we find the combinations of lengths that maximize the flip-flop diffusion rate. These experimental results combined with biophysical modeling studies allow us to propose a detailed mechanism for transmembrane flip-flop diffusion in HBM systems, which involves the bending of the alkyl tail of the proton carrier as the rate-determining step. Additional studies with an unbendable proton carrier further validate these mechanistic findings.
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18
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Goetz GH, Shalaeva M, Caron G, Ermondi G, Philippe L. Relationship between Passive Permeability and Molecular Polarity Using Block Relevance Analysis. Mol Pharm 2017; 14:386-393. [DOI: 10.1021/acs.molpharmaceut.6b00724] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gilles H. Goetz
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research & Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Marina Shalaeva
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research & Development, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Giulia Caron
- Molecular
Biotechnology and Health Sciences Department, University of Torino, via Quarello 15, 10135 Torino, Italy
| | - Giuseppe Ermondi
- Molecular
Biotechnology and Health Sciences Department, University of Torino, via Quarello 15, 10135 Torino, Italy
| | - Laurence Philippe
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research & Development, Pfizer Inc., Groton, Connecticut 06340, United States
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19
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Dickson CJ, Hornak V, Pearlstein RA, Duca JS. Structure–Kinetic Relationships of Passive Membrane Permeation from Multiscale Modeling. J Am Chem Soc 2016; 139:442-452. [DOI: 10.1021/jacs.6b11215] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Callum J. Dickson
- Computer-Aided Drug Discovery,
Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Viktor Hornak
- Computer-Aided Drug Discovery,
Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Robert A. Pearlstein
- Computer-Aided Drug Discovery,
Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jose S. Duca
- Computer-Aided Drug Discovery,
Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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20
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Silver LL. A Gestalt approach to Gram-negative entry. Bioorg Med Chem 2016; 24:6379-6389. [DOI: 10.1016/j.bmc.2016.06.044] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/12/2016] [Accepted: 06/22/2016] [Indexed: 01/01/2023]
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21
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Krämer SD, Aschmann HE, Hatibovic M, Hermann KF, Neuhaus CS, Brunner C, Belli S. When barriers ignore the "rule-of-five". Adv Drug Deliv Rev 2016; 101:62-74. [PMID: 26877103 DOI: 10.1016/j.addr.2016.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 01/27/2016] [Accepted: 02/03/2016] [Indexed: 12/20/2022]
Abstract
Why are a few drugs with properties beyond the rule of 5 (bRo5) absorbed across the intestinal mucosa while most other bRo5 compounds are not? Are such exceptional bRo5 compounds exclusively taken up by carrier-mediated transport or are they able to permeate the lipid bilayer (passive lipoidal diffusion)? Our experimental data with liposomes indicate that tetracycline, which violates one rule of the Ro5, and rifampicin, violating three of the rules, significantly permeate a phospholipid bilayer with kinetics similar to labetalol and metoprolol, respectively. Published data from experimental work and molecular dynamics simulations suggest that the formation of intramolecular H-bonds and the possibility to adopt an elongated shape besides the presence of a significant fraction of net neutral species facilitate lipid bilayer permeation. As an alternative to lipid bilayer permeation, carrier proteins can be targeted to improve absorption, with the potential drawbacks of drug-drug interactions and non-linear pharmacokinetics.
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Affiliation(s)
- Stefanie D Krämer
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland.
| | - Hélène E Aschmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Maja Hatibovic
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Katharina F Hermann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Claudia S Neuhaus
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Cyrill Brunner
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Vladimir-Prelog-Weg 4, CH-8093 Zurich, Switzerland
| | - Sara Belli
- Pharmaceutical Sciences, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Grenzacherstrasse 124, CH-4070 Basel, Switzerland
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22
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Ayee MAA, Roth CW, Akpa BS. Structural perturbation of a dipalmitoylphosphatidylcholine (DPPC) bilayer by warfarin and its bolaamphiphilic analogue: A molecular dynamics study. J Colloid Interface Sci 2016; 468:227-237. [PMID: 26852346 PMCID: PMC4762473 DOI: 10.1016/j.jcis.2016.01.056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 01/24/2016] [Accepted: 01/26/2016] [Indexed: 12/26/2022]
Abstract
Compounds with nominally similar biological activity may exhibit differential toxicity due to differences in their interactions with cell membranes. Many pharmaceutical compounds are amphiphilic and can be taken up by phospholipid bilayers, interacting strongly with the lipid-aqueous interface whether or not subsequent permeation through the bilayer is possible. Bolaamphiphilic compounds, which possess two hydrophilic ends and a hydrophobic linker, can likewise undergo spontaneous uptake by bilayers. While membrane-spanning bolaamphiphiles can stabilize membranes, small molecules with this characteristic have the potential to create membrane defects via disruption of bilayer structure and dynamics. When compared to the amphiphilic therapeutic anticoagulant, warfarin, the bolaamphiphilic analogue, brodifacoum, exhibits heightened toxicity that goes beyond superior inhibition of the pharmacological target enzyme. We explore, herein, the consequences of anticoagulant accumulation in a dipalmitoylphosphatidylcholine (DPPC) bilayer. Coarse-grained molecular dynamics simulations reveal that permeation of phospholipid bilayers by brodifacoum causes a disruption of membrane barrier function that is driven by the bolaamphiphilic nature and size of this molecule. We find that brodifacoum partitioning into bilayers causes membrane thinning and permeabilization and promotes lipid flip-flop - phenomena that are suspected to play a role in triggering cell death. These phenomena are either absent or less pronounced in the case of the less toxic, amphiphilic compound, warfarin.
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Affiliation(s)
- Manuela Aseye Ayele Ayee
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton St., Chicago, IL 60607, USA; Department of Medicine, University of Illinois at Chicago, 909 S. Wolcott Ave., Chicago, IL 60612, USA.
| | - Charles William Roth
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton St., Chicago, IL 60607, USA.
| | - Belinda Sena Akpa
- Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton St., Chicago, IL 60607, USA; Department of Molecular Biomedical Sciences, North Carolina State University, 1060 William Moore Dr., Raleigh, NC 27607, USA.
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23
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Grumetto L, Russo G, Barbato F. Polar interactions drug/phospholipids estimated by IAM-HPLC vs cultured cell line passage data: Their relationships and comparison of their effectiveness in predicting drug human intestinal absorption. Int J Pharm 2016; 500:275-90. [PMID: 26780120 DOI: 10.1016/j.ijpharm.2016.01.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/09/2016] [Indexed: 10/22/2022]
Abstract
The relationships between data of passage through Caco-2 cultured cell lines (log Papp), taken from the literature, for 38 structurally unrelated compounds and both n-octanol lipophilicity parameters (log P(N) and log D(7.4)) and phospholipid affinity indexes were investigated. Phospholipid affinity(log k W(IAM)) was experimentally determined by HPLC on two different phospholipid stationary phases and the polar/electrostatic interaction component drug/phospholipids (Δ log k W(IAM)) was calculated according to a method we previously proposed. Log Papp moderately related to lipophilicity values measured at pH 7.4 (log D(7.4)), according to a parabolic pattern, but poorly related with log k W(IAM). Furthermore, a significant inverse linear relationship with Δ l og k W(IAM) values was only observed for the analytes with m.w. >300 Da, for which paracellular diffusion can be considered a minor transport route in vivo. Indeed, it has been reported that Caco-2 passage data also encode secondary passage mechanisms, which participate in a different extent to the jejunal absorption in vivo and cannot be directly equated to the corresponding human in situ log Peff values, unless a normalization is performed. In an attempt to elucidate this issue, 47 structurally unrelated compounds whose cultured cell line passage data were corrected for the effects of the aqueous boundary layer and paracellular permeability, so as to express transcellular intrinsic permeability, log P 0(Caco-2/MDCK), were also considered. Highly significant inverse linear relationships were observed between log P 0(Caco-2/MDCK) and Δlog k W(IAM) values from both IAM.PC.MG (r(2)=0.765) and IAM.PC.DD2 (r(2)=0.806) stationary phases whereas the relationships with either lipophilicity in n-octanol or log k W(IAM) values were very poor. The results of the present study, in complete agreement with those of our recent study on the relationships between jejunal absorption data measured in situ and Δ log k W(IAM) values, confirm the soundness of Δ log k W(IAM) parameters in the prediction of the intestinal absorption of drugs. From a mechanistic point of view, they suggest that the polar/electrostatic forces between drugs and phospholipids play a major role in the passage through biomembranes.
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Affiliation(s)
- Lucia Grumetto
- Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano, 49 I-80131 Naples, Italy
| | - Giacomo Russo
- Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano, 49 I-80131 Naples, Italy
| | - Francesco Barbato
- Dipartimento di Farmacia, Università degli Studi di Napoli Federico II, Via D. Montesano, 49 I-80131 Naples, Italy.
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24
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Quantitative aspects of drug permeation across in vitro and in vivo barriers. Eur J Pharm Sci 2015; 87:30-46. [PMID: 26493585 DOI: 10.1016/j.ejps.2015.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 01/09/2023]
Abstract
The kinetics of permeation across epithelial and endothelial cell sheets and across cell membranes is determinant for the pharmacokinetics of a drug. In vitro transport experiments with cultured cells or artificial barriers have tremendously improved the predictability of the in vivo behaviour of tested compounds. This article focuses on the parameters and calculation methods that are used to describe permeation quantitatively, with a focus on in vitro experiments and the prediction of intestinal absorption and blood-brain barrier passage. It shows under which in vitro experimental conditions standard calculations are adequate and under which conditions equations should be adapted to the experimental details. The impact of volume differences between donor and receiver compartments, pH gradients, addition of albumin, accumulation in the barrier and unidirectional transport by an efflux transporter on the results is shown in simulations. The article should make researchers aware of experimental factors that affect the outcome of a permeation experiment and how to account for this during data analysis. Finally, strategies to predict the in vivo behaviour of a compound based on the in vitro data are discussed. The goal of the article is to support researchers in choosing experimental conditions and calculation methods that deliver appropriate and reproducible results in permeation studies in vitro.
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25
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Grumetto L, Russo G, Barbato F. Relationships between human intestinal absorption and polar interactions drug/phospholipids estimated by IAM–HPLC. Int J Pharm 2015; 489:186-94. [DOI: 10.1016/j.ijpharm.2015.04.062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 04/16/2015] [Accepted: 04/22/2015] [Indexed: 11/29/2022]
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26
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Martiel I, Baumann N, Vallooran JJ, Bergfreund J, Sagalowicz L, Mezzenga R. Oil and drug control the release rate from lyotropic liquid crystals. J Control Release 2015; 204:78-84. [DOI: 10.1016/j.jconrel.2015.02.034] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 02/19/2015] [Accepted: 02/23/2015] [Indexed: 12/14/2022]
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27
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Boström ML, Berglund O. Influence of pH-dependent aquatic toxicity of ionizable pharmaceuticals on risk assessments over environmental pH ranges. WATER RESEARCH 2015; 72:154-61. [PMID: 25262444 DOI: 10.1016/j.watres.2014.08.040] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 08/13/2014] [Accepted: 08/26/2014] [Indexed: 05/22/2023]
Abstract
Due to variation in pH, ionizable pharmaceuticals entering aquatic environments experience different degrees of ionization, which may affect toxicity. Using data from toxicity testing at only neutral pH may potentially under- or overestimate actual toxicity at pH ranges found in natural aquatic environments. Here we show relative pH-dependent acute toxicity to Daphnia magna for the pharmaceutical weak bases fluoxetine and sertraline, as well as the weak acids naproxen, diclofenac, ibuprofen and ketoprofen. A probabilistic modelling approach using the pH-dependent toxicity data for D. magna and an environmental pH distribution based on over 4000 European running waters from 21 countries predicted that environmental toxicity for the weak bases may be underestimated if pH 7 was assumed. The model predicted median underestimation by a factor of 3, with 90% of the model results ranging from 1 to 6. Consequently, due to the slightly basic nature of the European running waters, weak acid toxicity may be overestimated by a factor of 2. Predicted median toxicity was 0.5 of that assuming pH 7 with 90% of the results ranging from 0.03 to 5. Because aquatic pH exhibits large variation both within and between countries, we advise the use of site-specific risk assessments for ionizable pharmaceuticals in making informed water management decisions.
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Affiliation(s)
- Marja Lena Boström
- Aquatic Ecology, Biology Department, Lund University, P.O. Box 117, 221 00 Lund, Sweden.
| | - Olof Berglund
- Aquatic Ecology, Biology Department, Lund University, P.O. Box 117, 221 00 Lund, Sweden
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28
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Potter T, Ermondi G, Newbury G, Caron G. Relating Caco-2 permeability to molecular properties using block relevance analysis. MEDCHEMCOMM 2015. [DOI: 10.1039/c4md00470a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New insights into physicochemical drivers for Caco-2 permeability have been gained using a modelling technique known as block relevance analysis.
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Affiliation(s)
- T. Potter
- Cyprotex Discovery Limited
- Macclesfield
- UK
| | - G. Ermondi
- CASSMedChem Research Group
- Molecular Biotechnology and Health Sciences Department
- University of Turin
- Italy
| | - G. Newbury
- Cyprotex Discovery Limited
- Macclesfield
- UK
| | - G. Caron
- CASSMedChem Research Group
- Molecular Biotechnology and Health Sciences Department
- University of Turin
- Italy
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29
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Indexes of polar interactions between ionizable drugs and membrane phospholipids measured by IAM–HPLC: Their relationships with data of Blood–Brain Barrier passage. Eur J Pharm Sci 2014; 65:139-46. [DOI: 10.1016/j.ejps.2014.09.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/10/2014] [Accepted: 09/13/2014] [Indexed: 11/19/2022]
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30
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Filipe HAL, Salvador A, Silvestre JM, Vaz WLC, Moreno MJ. Beyond Overton’s Rule: Quantitative Modeling of Passive Permeation through Tight Cell Monolayers. Mol Pharm 2014; 11:3696-706. [DOI: 10.1021/mp500437e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- H. A. L. Filipe
- Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
- Centro
de Neurociências e Biologia Celular, Universidade de Coimbra, 3000-214 Coimbra, Portugal
| | - A. Salvador
- Centro
de Neurociências e Biologia Celular, Universidade de Coimbra, 3000-214 Coimbra, Portugal
- Chemistry
Department, FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
| | - J. M. Silvestre
- Centro
de Neurociências e Biologia Celular, Universidade de Coimbra, 3000-214 Coimbra, Portugal
| | - W. L. C. Vaz
- Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
- Chemistry
Department, FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
| | - M. J. Moreno
- Centro de Química de Coimbra, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
- Centro
de Neurociências e Biologia Celular, Universidade de Coimbra, 3000-214 Coimbra, Portugal
- Chemistry
Department, FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra, Portugal
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31
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Abraham MH. Human Intestinal Absorption—Neutral Molecules and Ionic Species. J Pharm Sci 2014; 103:1956-1966. [DOI: 10.1002/jps.24024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/01/2014] [Accepted: 05/05/2014] [Indexed: 11/11/2022]
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32
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Sharom FJ. Complex Interplay between the P-Glycoprotein Multidrug Efflux Pump and the Membrane: Its Role in Modulating Protein Function. Front Oncol 2014; 4:41. [PMID: 24624364 PMCID: PMC3939933 DOI: 10.3389/fonc.2014.00041] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/17/2014] [Indexed: 11/16/2022] Open
Abstract
Multidrug resistance in cancer is linked to expression of the P-glycoprotein multidrug transporter (Pgp, ABCB1), which exports many structurally diverse compounds from cells. Substrates first partition into the bilayer and then interact with a large flexible binding pocket within the transporter's transmembrane regions. Pgp has been described as a hydrophobic vacuum cleaner or an outwardly directed drug/lipid flippase. Recent X-ray crystal structures have shed some light on the nature of the drug-binding pocket and suggested routes by which substrates can enter it from the membrane. Detergents have profound effects on Pgp function, and several appear to be substrates. Biochemical and biophysical studies in vitro, some using purified reconstituted protein, have explored the effects of the membrane environment. They have demonstrated that Pgp is involved in a complex relationship with its lipid environment, which modulates the behavior of its substrates, as well as various functions of the protein, including ATP hydrolysis, drug binding, and drug transport. Membrane lipid composition and fluidity, phospholipid headgroup and acyl chain length all influence Pgp function. Recent studies focusing on thermodynamics and kinetics have revealed some important principles governing Pgp-lipid and substrate-lipid interactions, and how these affect drug-binding and transport. In some cells, Pgp is associated with cholesterol-rich microdomains, which may modulate its functions. The relationship between Pgp and cholesterol remains an open question; however, it clearly affects several aspects of its function in addition to substrate-membrane partitioning. The action of Pgp modulators appears to depend on their membrane permeability, and membrane fluidizers and surfactants reverse drug resistance, likely via an indirect mechanism. A detailed understanding of how the membrane affects Pgp substrates and Pgp's catalytic cycle may lead to new strategies to combat clinical drug resistance.
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Affiliation(s)
- Frances Jane Sharom
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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33
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Pypendop BH, Ilkiw JE, Shilo-Benjamini Y. Bioavailability of morphine, methadone, hydromorphone, and oxymorphone following buccal administration in cats. J Vet Pharmacol Ther 2013; 37:295-300. [DOI: 10.1111/jvp.12090] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 10/08/2013] [Indexed: 11/29/2022]
Affiliation(s)
- B. H. Pypendop
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - J. E. Ilkiw
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - Y. Shilo-Benjamini
- Department of Surgical and Radiological Sciences; School of Veterinary Medicine; University of California; Davis CA USA
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34
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A liposomal fluorescence assay to study permeation kinetics of drug-like weak bases across the lipid bilayer. J Control Release 2013; 173:102-9. [PMID: 24211703 DOI: 10.1016/j.jconrel.2013.10.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/26/2013] [Accepted: 10/29/2013] [Indexed: 02/04/2023]
Abstract
Lipid bilayer permeation is considered the major route for in vivo barrier passage of drugs. Despite this fact, no technique is currently available to measure the kinetics of permeation across a single lipid bilayer of structurally unrelated drug-like solutes. We developed a liposomal fluorescence assay capable to determine permeation kinetics of basic drug-like solutes across lipid bilayers. The assay is based on the hypothesis that permeation of a weak base along a concentration gradient results in net proton release at the cis-side and net proton capture at the trans-side of the bilayer. The resulting pH changes were monitored with pH-sensitive fluorophores: Test compounds were incubated with liposomes containing a pH-sensitive fluorophore at the bilayer surfaces or in the aqueous lumen and fluorescence changes were monitored with a stopped-flow apparatus in solution or by total internal reflection fluorescence microscopy with surface-captured liposomes on a microfluidic platform. Incubation with lipophilic basic drugs resulted in the expected fluorescence changes while incubation with compounds without basic functionality or high polarity did not affect fluorescence. Kinetics of fluorescence changes followed bi-exponential functions. Logarithmic permeation coefficients (logPermapp) determined in solution and by microfluidics technology showed a good correlation (r(2)=0.94, n=7) and logPermapp increased with increasing lipophilicity. Neither diffusion in the aqueous phase nor partitioning into the bilayer was rate-limiting. PEGylation of 2% of the liposomal lipids reduced Permapp by a factor ~300. In conclusion, the presented liposomal fluorescence assay is capable to determine permeation kinetics of weak basic drug-like solutes across lipid bilayers. The method is adaptable to microfluidics technology for high-throughput measurements and can potentially be modified to work for weak acid solutes.
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Quignot N. Modeling bioavailability to organs protected by biological barriers. In Silico Pharmacol 2013; 1:8. [PMID: 25505653 PMCID: PMC4230447 DOI: 10.1186/2193-9616-1-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 05/05/2013] [Indexed: 01/16/2023] Open
Abstract
Computational pharmacokinetic (PK) modeling gives access to drug concentration vs. time profiles in target organs and allows better interpretation of clinical observations of therapeutic or toxic effects. Physiologically-based PK (PBPK) models in particular, based on mechanistic descriptions of the body anatomy and physiology, may also help to extrapolate in vitro or animal data to human. Once in the systemic circulation, a chemical has access to the microvasculature of every organ or tissue. However, its penetration in the brain, retina, thymus, spinal cord, testis, placenta,… may be limited or even fully prevented by dynamic physiological blood-tissue barriers. Those barriers are both physical (involving tight junctions between adjacent cells) and biochemical (involving metabolizing enzymes and transporters). On those cases, correct mechanistic characterization of the passage (or not) of molecules through the barrier can be crucial for improved PBPK modeling and prediction. In parallel, attempts to understand and quantitatively characterize the processes involved in drug penetration of physiological barriers have led to the development of several in vitro experimental models. Data from such assays are very useful to calibrate PBPK models. We review here those in vitro and computational models, highlighting the challenges and perspectives for in vitro and computational models to better assess drug availability to target tissues.
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Affiliation(s)
- Nadia Quignot
- Bioengineering Department, Chair of Mathematical Modeling for Systems Toxicology, Université de Technologie de Compiègne, Royallieu Research Center, Compiègne, 60200 France ; LA-SER, Strategy and Decision Analytics, 10 place de la Catalogne, Paris, 75014 France
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Filipe HAL, Coreta-Gomes FM, Velazquez-Campoy A, Almeida AR, Peixoto AF, Pereira MM, Vaz WLC, Moreno MJ. Synthesis and Characterization of a Lipidic Alpha Amino Acid: Solubility and Interaction with Serum Albumin and Lipid Bilayers. J Phys Chem B 2013; 117:3439-48. [DOI: 10.1021/jp307874v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hugo A. L. Filipe
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | | | - Adrian Velazquez-Campoy
- Institute of Biocomputation
and Physics of Complex Systems (BIFI), Universidad de Zaragoza, Unidad Asociada BIFI-IQFR, CSIC, Zaragoza,
Spain
- Fundación ARAID, Diputación General de Aragón, Spain
| | - Ana R. Almeida
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - Andreia F. Peixoto
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - Mariette M. Pereira
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - Winchil L. C. Vaz
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - Maria J. Moreno
- Departamento de
Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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37
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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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38
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Di L, Artursson P, Avdeef A, Ecker GF, Faller B, Fischer H, Houston JB, Kansy M, Kerns EH, Krämer SD, Lennernäs H, Sugano K. Evidence-based approach to assess passive diffusion and carrier-mediated drug transport. Drug Discov Today 2012; 17:905-12. [DOI: 10.1016/j.drudis.2012.03.015] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 03/20/2012] [Accepted: 03/30/2012] [Indexed: 10/28/2022]
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39
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Martins PT, Velazquez-Campoy A, Vaz WLC, Cardoso RMS, Valério J, Moreno MJ. Kinetics and Thermodynamics of Chlorpromazine Interaction with Lipid Bilayers: Effect of Charge and Cholesterol. J Am Chem Soc 2012; 134:4184-95. [DOI: 10.1021/ja209917q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Patrícia T. Martins
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Adrian Velazquez-Campoy
- Institute of Biocomputation
and Physics of Complex Systems (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain, Unidad Asociada BIFI-IQFR,
CSIC, Zaragoza, Spain
- Fundación ARAID, Diputación General de Aragón, Spain
| | - Winchil L. C. Vaz
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Renato M. S. Cardoso
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
| | - Joana Valério
- Instituto de Tecnologia Química e Biológica − UNL, Av.
da República-EAN, 2780-157 Oeiras, Portugal
| | - Maria João Moreno
- Chemistry Department FCTUC, Largo D. Dinis, Rua Larga, 3004-535 Coimbra,
Portugal
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40
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Kuhn P, Eyer K, Allner S, Lombardi D, Dittrich PS. A Microfluidic Vesicle Screening Platform: Monitoring the Lipid Membrane Permeability of Tetracyclines. Anal Chem 2011; 83:8877-85. [DOI: 10.1021/ac201410m] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Phillip Kuhn
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093 Zurich, Switzerland
| | - Klaus Eyer
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093 Zurich, Switzerland
| | - Steffen Allner
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093 Zurich, Switzerland
| | - Dario Lombardi
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093 Zurich, Switzerland
| | - Petra S. Dittrich
- ETH Zurich, Department of Chemistry and Applied Biosciences, CH-8093 Zurich, Switzerland
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41
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Yousefi R, Khalafi-Nezhad A, Soltani Rad MN, Behrouz S, Panahi F, Esmaili M, Ghaffari SM, Niazi A, Moosavi-Movahedi AA. Structure–cytotoxicity relationship of a novel series of miconazole-like compounds. Med Chem Res 2011. [DOI: 10.1007/s00044-011-9716-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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42
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Franzen U, Vermehren C, Jensen H, Østergaard J. Physicochemical characterization of a PEGylated liposomal drug formulation using capillary electrophoresis. Electrophoresis 2011; 32:738-48. [PMID: 21365657 DOI: 10.1002/elps.201000552] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 12/21/2010] [Accepted: 12/27/2010] [Indexed: 11/12/2022]
Abstract
In this work, the applicability of using CE to perform a physicochemical characterization of a PEGylated liposomal drug formulation of the anti-cancer agent oxaliplatin was examined. Characterization of the liposomal drug formulation using CE instrumentation encompassed: determination of the electrophoretic mobilities, size determination by Taylor dispersion analysis and interaction studies. Electrophoretic mobilities determined by CE were compared with the results obtained by laser Doppler electrophoresis, which were found to be subject to larger variation. Average hydrodynamic diameters of the liposome preparations, as determined by Taylor dispersion analysis, were in the range of 61-84 nm and were compared with the results obtained by dynamic light scattering. Interactions between oxaliplatin (and paracetamol) and the PEGylated liposome were non-detectable by CE frontal analysis as well as by liposome electrokinetic chromatography. In contrast, for the more lipophilic compound propranolol, apparent liposome-aqueous phase distribution coefficients (D(lip) ) were successfully determined by both electrokinetic chromatography (log D(lip) =2.10) and by CE frontal analysis (log D(lip) =2.14). It is envisioned that CE and capillary-based techniques, including Taylor dispersion analysis, will be useful tools for the characterization of nanoparticulate (e.g. liposomal) drug formulations.
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Affiliation(s)
- Ulrik Franzen
- Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark
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Neuwoehner J, Escher BI. The pH-dependent toxicity of basic pharmaceuticals in the green algae Scenedesmus vacuolatus can be explained with a toxicokinetic ion-trapping model. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 101:266-275. [PMID: 21084122 DOI: 10.1016/j.aquatox.2010.10.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 10/13/2010] [Accepted: 10/19/2010] [Indexed: 05/30/2023]
Abstract
Several previous studies revealed that pharmaceuticals with aliphatic amine function exhibit a higher toxicity toward algae than toward other aquatic organisms. Here we investigated the pH-dependent toxicity of the five basic pharmaceuticals fluoxetine, its metabolite norfluoxetine, propranolol, lidocaine, and trimipramine. For all of them, the toxicity increased with increasing pH when aqueous effect concentrations were considered. Since these pharmaceuticals contain a basic amine group that is protonated and thus positively charged at physiological pH and because algae are capable of biological homeostasis, i.e., pH inside the algal cell remains virtually independent of variable external pH, the speciation of aliphatic amines can be different inside the algal cell compared to the external medium. Therefore, we hypothesized that the high toxicity of aliphatic amines in algae is a toxicokinetic effect caused by speciation and not a toxicodynamic effect caused by a specific mode of toxic action. This hypothesis also implies that internal effect concentrations are independent on external pH. On this basis we developed a simple toxicokinetic model, which assumes that only the neutral molecule is bioavailable and can pass the plasma membrane. This assumption is likely to be valid at pH values down to two units below the acidity constant (pK(a)). For lower pH values a more complex model would have to be evoked that includes, an, albeit smaller, permeability of the charged species. For pH>pK(a)-2, we can safely assume that the outer membrane serves as insulator and that the charged species is formed inside the cell according to the pH in the cytoplasm. Thus this toxicokinetic model is an ion-trapping model. The input parameters of this model are the measured aqueous effect concentrations determined as a function of pH and the membrane-water partitioning, which was modelled by the liposome-water partition coefficients of the neutral and cationic species. They were deduced from experimentally determined liposome-water distribution ratios at various pH values measured with an equilibrium dialysis method. The modelled internal effect concentrations were independent of the external pH and effective membrane burdens were in the same range as for other baseline toxicants found in the literature for algae, daphnids and fish. These results confirm that the higher algal toxicity of pharmaceuticals with an aliphatic amine group can be explained by a toxicokinetic effect and that these pharmaceuticals do not exhibit a specific mode of action in algae but act as baseline toxicants.
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Affiliation(s)
- Judith Neuwoehner
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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44
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Horobin RW, Stockert JC. Uptake and localization mechanisms of fluorescent and colored lipid probes. 1. Physicochemistry of probe uptake and localization, and the use of QSAR models for selectivity prediction. Biotech Histochem 2010; 86:379-93. [DOI: 10.3109/10520295.2010.515489] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- RW Horobin
- School of Life Sciences, The University of Glasgow, University Avenue,
Glasgow G12 8QQ, Scotland, UK
| | - JC Stockert
- Department of Biology, Faculty of Sciences, Autonomous University of Madrid,
Cantoblanco, Madrid 28049
- Center for Biological Research, High Council of Scientific Research,
Madrid 28040, Spain
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