1
|
Erimban S, Daschakraborty S. Translocation of a hydroxyl functionalized carbon dot across a lipid bilayer: an all-atom molecular dynamics simulation study. Phys Chem Chem Phys 2020; 22:6335-6350. [DOI: 10.1039/c9cp05999g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Passive permeation of CD across lipid bilayer is almost impossible. Forced permeation results membrane rupture.
Collapse
Affiliation(s)
- Shakkira Erimban
- Department of Chemistry
- Indian Institute of Technology Patna
- Bihar 801106
- India
| | | |
Collapse
|
2
|
Dahlgren D, Lennernäs H. Intestinal Permeability and Drug Absorption: Predictive Experimental, Computational and In Vivo Approaches. Pharmaceutics 2019; 11:pharmaceutics11080411. [PMID: 31412551 PMCID: PMC6723276 DOI: 10.3390/pharmaceutics11080411] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/01/2019] [Accepted: 08/07/2019] [Indexed: 02/06/2023] Open
Abstract
The main objective of this review is to discuss recent advancements in the overall investigation and in vivo prediction of drug absorption. The intestinal permeability of an orally administered drug (given the value Peff) has been widely used to determine the rate and extent of the drug’s intestinal absorption (Fabs) in humans. Preclinical gastrointestinal (GI) absorption models are currently in demand for the pharmaceutical development of novel dosage forms and new drug products. However, there is a strong need to improve our understanding of the interplay between pharmaceutical, biopharmaceutical, biochemical, and physiological factors when predicting Fabs and bioavailability. Currently, our knowledge of GI secretion, GI motility, and regional intestinal permeability, in both healthy subjects and patients with GI diseases, is limited by the relative inaccessibility of some intestinal segments of the human GI tract. In particular, our understanding of the complex and highly dynamic physiology of the region from the mid-jejunum to the sigmoid colon could be significantly improved. One approach to the assessment of intestinal permeability is to use animal models that allow these intestinal regions to be investigated in detail and then to compare the results with those from simple human permeability models such as cell cultures. Investigation of intestinal drug permeation processes is a crucial biopharmaceutical step in the development of oral pharmaceutical products. The determination of the intestinal Peff for a specific drug is dependent on the technique, model, and conditions applied, and is influenced by multiple interactions between the drug molecule and the biological membranes.
Collapse
Affiliation(s)
- David Dahlgren
- Department of Pharmacy, Uppsala University, Box 580 SE-751 23 Uppsala, Sweden
| | - Hans Lennernäs
- Department of Pharmacy, Uppsala University, Box 580 SE-751 23 Uppsala, Sweden.
| |
Collapse
|
3
|
David Jebaraj D, Utsumi H, Milton Franklin Benial A. Low-frequency ESR studies on permeable and impermeable deuterated nitroxyl radicals in corn oil solution. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:257-264. [PMID: 29205482 DOI: 10.1002/mrc.4686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/13/2017] [Accepted: 11/16/2017] [Indexed: 06/07/2023]
Abstract
Low-frequency electron spin resonance studies were performed for 2 mM concentration of deuterated permeable and impermeable nitroxyl spin probes, 3-methoxycarbonyl-2,2,5,5-tetramethyl-pyrrolidine-1-oxyl and 3-carboxy-2,2,5,5,-tetramethyl-1-pyrrolidinyloxy in pure water and various concentrations of corn oil solution. The electron spin resonance parameters such as the line width, hyperfine coupling constant, g factor, rotational correlation time, permeability, and partition parameter were estimated. The broadening of line width was observed for nitroxyl radicals in corn oil mixture. The rotational correlation time increases with increasing concentration of corn oil, which indicates the less mobile nature of spin probe in corn oil mixture. The membrane permeability and partition parameter values were estimated as a function of corn oil concentration, which reveals that the nitroxyl radicals permeate equally into the aqueous phase and oil phase at the corn oil concentration of 50%. The electron spin resonance spectra demonstrate the permeable and impermeable nature of nitroxyl spin probes. From these results, the corn oil concentration was optimized as 50% for phantom studies. In this work, the corn oil and pure water mixture phantom models with various viscosities correspond to plasma membrane, and whole blood membrane with different hematocrit levels was studied for monitoring the biological characteristics and their interactions with permeable nitroxyl spin probe. These results will be useful for the development of electron spin resonance and Overhauser-enhanced magnetic resonance imaging modalities in biomedical applications.
Collapse
Affiliation(s)
- D David Jebaraj
- Department of Physics, The American College, Madurai, Tamil Nadu, 625 002, India
| | - Hideo Utsumi
- Innovation Center for Medical Redox Navigation, Kyushu University, Fukuoka, 812-8582, Japan
| | | |
Collapse
|
4
|
Casalegno M, Raos G, Sello G. From dioxin to dioxin congeners: understanding the differences in hydrophobic aggregation in water and absorption into lipid membranes by means of atomistic simulations. Phys Chem Chem Phys 2016; 18:17731-9. [DOI: 10.1039/c6cp01728b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Molecular dynamics simulations indicate that dioxin likely accumulates in cell membranes more than its congeners (anthracene, tetrahydrodioxin, 3,3′,5,5′-tetrachlorobiphenyl, and 1,2-dihydroxytetrahydrodibenzo-p-dioxin).
Collapse
Affiliation(s)
- Mosé Casalegno
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “G. Natta”
- Politecnico di Milano
- 20131 Milano
- Italy
| | - Guido Raos
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “G. Natta”
- Politecnico di Milano
- 20131 Milano
- Italy
| | - Guido Sello
- Dipartimento di Chimica
- Università degli Studi di Milano
- I-20133 Milano
- Italy
| |
Collapse
|
5
|
Dahlgren D, Roos C, Sjögren E, Lennernäs H. Direct In Vivo Human Intestinal Permeability (Peff ) Determined with Different Clinical Perfusion and Intubation Methods. J Pharm Sci 2014; 104:2702-26. [PMID: 25410736 DOI: 10.1002/jps.24258] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 10/17/2014] [Accepted: 10/17/2014] [Indexed: 12/21/2022]
Abstract
Regional in vivo human intestinal effective permeability (Peff ) is calculated by measuring the disappearance rate of substances during intestinal perfusion. Peff is the most relevant parameter in the prediction of rate and extent of drug absorption from all parts of the intestine. Today, human intestinal perfusions are not performed on a routine basis in drug development. Therefore, it would be beneficial to increase the accuracy of the in vitro and in silico tools used to evaluate the intestinal Peff of novel drugs. This review compiles historical Peff data from 273 individual measurements of 80 substances from 61 studies performed in all parts of the human intestinal tract. These substances include: drugs, monosaccharaides, amino acids, dipeptides, vitamins, steroids, bile acids, ions, fatty acids, and water. The review also discusses the determination and prediction of Peff using in vitro and in silico methods such as quantitative structure-activity relationship, Caco-2, Ussing chamber, animal intestinal perfusion, and physiologically based pharmacokinetic (PBPK) modeling. Finally, we briefly outline how to acquire accurate human intestinal Peff data by deconvolution of plasma concentration-time profiles following regional intestinal bolus dosing.
Collapse
Affiliation(s)
- David Dahlgren
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| | - Carl Roos
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| | - Erik Sjögren
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| | - Hans Lennernäs
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
| |
Collapse
|
6
|
Smith D, Artursson P, Avdeef A, Di L, Ecker GF, Faller B, Houston JB, Kansy M, Kerns EH, Krämer SD, Lennernäs H, van de Waterbeemd H, Sugano K, Testa B. Passive Lipoidal Diffusion and Carrier-Mediated Cell Uptake Are Both Important Mechanisms of Membrane Permeation in Drug Disposition. Mol Pharm 2014; 11:1727-38. [DOI: 10.1021/mp400713v] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Per Artursson
- Department of Pharmacy, Biomedical Centre, Uppsala University, S-752 63 Uppsala, Box 580, Sweden
| | - Alex Avdeef
- 1732 First
Avenue, #102, New York, New
York 10128, United States
| | - Li Di
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., Groton, Connecticut 06340, United States
| | - Gerhard F. Ecker
- Department of Medicinal Chemistry, University of Vienna,
Althanstrasse, 141090 Wien, Austria
| | - Bernard Faller
- Novartis Institutes for Biomedical Research, WSJ-350.3.04, CH-4002 Basel, Switzerland
| | - J. Brian Houston
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, U.K
| | - Manfred Kansy
- The Non-Clinical
Safety Department, F. Hoffmann-La Roche, CH-4070 Basel, Switzerland
| | - Edward H. Kerns
- National Center for Advancing Translational
Sciences, National Institutes of Health, 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | | | - Hans Lennernäs
- Department of Pharmacy, Biomedical Centre, Uppsala University, S-752 63 Uppsala, Box 580, Sweden
| | | | - Kiyohiko Sugano
- Research
Formulation, Sandwich Laboratories, Ramsgate Road, Sandwich, Kent CT13 9NJ, U.K
| | - Bernard Testa
- Department of Pharmacy, University Hospital Lausanne, CH-1011 Lausanne, Switzerland
| |
Collapse
|
7
|
Nitsche JM, Kasting GB. Permeability of fluid-phase phospholipid bilayers: assessment and useful correlations for permeability screening and other applications. J Pharm Sci 2013; 102:2005-2032. [PMID: 23605505 DOI: 10.1002/jps.23471] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 12/20/2012] [Accepted: 01/18/2013] [Indexed: 12/14/2022]
Abstract
Permeability data (P(lip/w) ) for liquid crystalline phospholipid bilayers composed of egg lecithin and dimyristoylphosphatidylcholine (DMPC) are analyzed in terms of a mathematical model that accounts for free surface area and chain-ordering effects in the bilayer as well as size and lipophilicity of the permeating species. Free surface area and chain ordering are largely determined by temperature and cholesterol content of the membrane, molecular size is represented by molecular weight, and lipophilicity of the barrier region is represented by the 1,9-decadiene/water partition coefficient, following earlier work by Xiang, Anderson, and coworkers. A correlating variable χ = MW(n) σ/(1 -σ) is used to link the results from different membrane systems, where different values of n are tried, and σ denotes a reduced phospholipid density. The group (1 -σ)/σ is a measure of free surface area, but can also be interpreted in terms of free volume. A single exponential function of χ is developed that is able to correlate 39 observations of P(lip/w) for different compounds in egg lecithin at low density, and 22 observations for acetic acid in DMPC at higher densities, spanning nine orders of magnitude to within an rms error for log 10 P(lip/w) of 0.20. The best fit found for n = 0.87 ultimately makes χ much closer to the ratio of molecular to free volumes than surface areas. The results serve as a starting point for estimating passive permeability of cell membranes to nonionized solutes as a function of temperature and cholesterol content of the membrane.
Collapse
Affiliation(s)
- Johannes M Nitsche
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York, 14260-4200.
| | - Gerald B Kasting
- James L. Winkle College of Pharmacy, University of Cincinnati Academic Health Center, Cincinnati, Ohio, 45267-0004
| |
Collapse
|
8
|
Carvalho CA, Olivares-Ortega C, Soto-Arriaza MA, Carmona-Ribeiro AM. Interaction of gramicidin with DPPC/DODAB bilayer fragments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:3064-71. [PMID: 22960286 DOI: 10.1016/j.bbamem.2012.08.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/09/2012] [Accepted: 08/10/2012] [Indexed: 10/28/2022]
Abstract
The interaction between the antimicrobial peptide gramicidin (Gr) and dipalmitoylphosphatidylcholine (DPPC)/dioctadecyldimethylammonium bromide (DODAB) 1:1 large unilamellar vesicles (LVs) or bilayer fragments (BFs) was evaluated by means of several techniques. The major methods were: 1) Gr intrinsic fluorescence and circular dichroism (CD) spectroscopy; 2) dynamic light scattering for sizing and zeta-potential analysis; 3) determination of the bilayer phase transition from extrinsic fluorescence of bilayer probes; 4) pictures of the dispersions for evaluation of coloidal stability over a range of time and NaCl concentration. For Gr in LVs, the Gr dimeric channel conformation is suggested from: 1) CD and intrinsic fluorescence spectra similar to those in trifluoroethanol (TFE); 2) KCl or glucose permeation through the LVs/Gr bilayer. For Gr in BFs, the intertwined dimeric, non-channel Gr conformation is evidenced by CD and intrinsic fluorescence spectra similar to those in ethanol. Both LVs and BFs shield Gr tryptophans against quenching by acrylamide but the Stern-Volmer quenching constant was slightly higher for Gr in BFs confirming that the peptide is more exposed to the water phase in BFs than in LVs. The DPPC/DODAB/Gr supramolecular assemblies may predict the behavior of other antimicrobial peptides in assemblies with lipids.
Collapse
Affiliation(s)
- Camilla A Carvalho
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CP 26077, CEP 05513-970, São Paulo, SP, Brazil
| | | | | | | |
Collapse
|
9
|
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]
|
10
|
Balaz S. Does transbilayer diffusion have a role in membrane transport of drugs? Drug Discov Today 2012; 17:1079-87. [PMID: 22705388 DOI: 10.1016/j.drudis.2012.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/07/2012] [Accepted: 06/08/2012] [Indexed: 10/28/2022]
Abstract
The existing consensus on coexistence of transbilayer diffusion and carrier-mediated transport as two main mechanisms for drugs crossing biological membranes was recently challenged by a systems biology group. Their transporters-only hypothesis is examined in this article using published experimental evidence. The main focus is on the key claim of their hypothesis, stating that 'the drug molecules cross pure phospholipid bilayers through transient pores that cannot form in the bilayers of cell membranes, and thus transbilayer drug transport does not exist in cells'. The analysis shows that the prior consensus remains a valid scientific view of the membrane transport of drugs.
Collapse
Affiliation(s)
- Stefan Balaz
- Albany College of Pharmacy and Health Sciences, Vermont Campus, Department of Pharmaceutical Sciences, Colchester, VT 05446, USA.
| |
Collapse
|
11
|
Adane ED, Liu Z, Xiang TX, Anderson BD, Leggas M. Pharmacokinetic modeling to assess factors affecting the oral bioavailability of the lactone and carboxylate forms of the lipophilic camptothecin analogue AR-67 in rats. Pharm Res 2011; 29:1722-36. [PMID: 22068278 DOI: 10.1007/s11095-011-0617-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 10/25/2011] [Indexed: 11/27/2022]
Abstract
PURPOSE Camptothecin analogues are anticancer drugs effective when dosed in protracted schedules. Such treatment is best suited for oral formulations. AR-67 is a novel lipophilic analogue with potent efficacy in preclinical models. Here we assessed factors that may influence its oral bioavailability in rats. METHODS Plasma pharmacokinetic (PK) studies were conducted following administration of AR-67 lactone or carboxylate doses alone or after pre-dosing with inhibitors of the efflux transporters P-gp and Bcrp. A population PK model that simultaneously fitted to oral and intravenous data was used to estimate the bioavailability (F) and clearance of AR-67. RESULTS An inverse Gaussian function was used as the oral input into the model and provided the best fits. Covariate analysis showed that the bioavailability of the lactone, but not its clearance, was dose dependent. Consistent with this observation, the bioavailability of AR-67 increased when animals were pretreated orally with GF120918 or Zosuquidar. CONCLUSION Absorption of AR-67 is likely affected by solubility of its lactone form and interaction with efflux pumps in the gut. AR-67 appears to be absorbed as the lactone form, most likely due to gastric pH favoring its formation and predominance. F increased at higher doses suggesting saturation of efflux mechanisms.
Collapse
MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- Acridines/administration & dosage
- Acridines/pharmacology
- Administration, Oral
- Animals
- Antineoplastic Agents, Phytogenic/administration & dosage
- Antineoplastic Agents, Phytogenic/blood
- Antineoplastic Agents, Phytogenic/chemistry
- Camptothecin/administration & dosage
- Camptothecin/analogs & derivatives
- Camptothecin/blood
- Carboxylic Acids/administration & dosage
- Carboxylic Acids/blood
- Carboxylic Acids/chemistry
- Female
- Lactones/administration & dosage
- Lactones/blood
- Lactones/chemistry
- Models, Biological
- Rats
- Rats, Sprague-Dawley
- Tetrahydroisoquinolines/administration & dosage
- Tetrahydroisoquinolines/pharmacology
- Topoisomerase I Inhibitors/administration & dosage
- Topoisomerase I Inhibitors/blood
- Topoisomerase I Inhibitors/chemistry
Collapse
Affiliation(s)
- Eyob D Adane
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, Kentucky 40536, USA
| | | | | | | | | |
Collapse
|
12
|
Cao Y, Xiang TX, Anderson BD. Development of Structure−Lipid Bilayer Permeability Relationships for Peptide-like Small Organic Molecules. Mol Pharm 2008; 5:371-88. [DOI: 10.1021/mp700100n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yichen Cao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536
| | - Tian-Xiang Xiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536
| | - Bradley D. Anderson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536
| |
Collapse
|
13
|
Chen IJ, Taneja R, Yin D, Seo PR, Young D, MacKerell AD, Polli JE. Chemical substituent effect on pyridine permeability and mechanistic insight from computational molecular descriptors. Mol Pharm 2006; 3:745-55. [PMID: 17140262 PMCID: PMC2526287 DOI: 10.1021/mp050096+] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The objective was (1) to evaluate the chemical substituent effect on Caco-2 permeability, using a congeneric series of pyridines, and (2) compare molecular descriptors from a computational chemistry approach against molecular descriptors from the Hansch approach for their abilities to explain the chemical substituent effect on pyridine permeability. The passive permeability of parent pyridine and 14 monosubstituted pyridines were measured across Caco-2 monolayers. Computational chemistry analysis was used to obtain the following molecular descriptions: solvation free energies, solvent accessible surface area, polar surface area, and cavitation energy. Results indicate that the parent pyridine was highly permeable and that chemical substitution was able to reduce pyridine permeability almost 20-fold. The substituent effect on permeability provided the following rank order: 3-COO- < 4-NH2 < 3-CONH2 < 3-Cl < 3-CHO < 3-OH < 3-CH2OH < 3-C6H5 < 3-NH2 < 3-CH2C6H5 < 3-C2H5 < 3-H < 3-CH3 < 3-F < 4-C6H5. This substituent effect was better explained via molecule descriptors from the computational chemistry approach than explained by classic descriptors from Hansch. Computational descriptors indicate that aqueous desolvation, but not membrane partitioning per se, dictated substituent effect on permeability.
Collapse
Affiliation(s)
- I-Jen Chen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - Rajneesh Taneja
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - Daxu Yin
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - Paul R. Seo
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - David Young
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - Alexander D. MacKerell
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| | - James E. Polli
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, 21201
| |
Collapse
|
14
|
Xiang TX, Anderson BD. Conformational structure, dynamics, and solvation energies of small alanine peptides in water and carbon tetrachloride. J Pharm Sci 2006; 95:1269-87. [PMID: 16625657 DOI: 10.1002/jps.20453] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The rate-limiting barrier for peptide transport across lipid bilayers is the nonpolar hydrocarbon interior. Permeating peptides may undergo conformational changes during their transfer from an aqueous solution into the barrier domain, thus facilitating peptide transport. To test this hypothesis, all-atom and explicit-solvent molecular dynamics (MD) simulations have been conducted on a series of small peptides, p-toluyl-Ala(n) (n = 0-3) used previously in transport experiments, to explore their conformational structures, dynamics and solvation free energies in water and carbon tetrachloride (CCl(4)). The conformations of the p-toluyl alanine di- and tri-peptides in water were found to be far from random coils, with P(II) and alpha(R) dominating but with smaller populations of seven-membered (c(7)) and five-membered rings (c(5)). In contrast, the seven-membered ring, c(7), along with c(5) dominated in CCl(4). These results indicate that the conformational preferences of the alanine peptides are highly sensitive to solvent. Dynamically, stable seven-membered ring formation occurred on a time scale of 10 ps while larger ring-sizes (e.g., 10-membered rings) were observed much less frequently. The values of adjacent torsional angles (phi(1), psi(1)) were dependent on neighboring torsional angles. Thermal motions of neighboring torsions leading to transitions between c(7), c(5), alpha(R), and P(II) conformers were highly cooperative while longer range correlations between transitions of adjacent sets of torsions (phi(1), psi(1)) and (phi(2), psi(2)) were less evident. Peptide folding in CCl(4) lowers the intramolecular electrostatic energies. This, along with hydrophobic interactions, favors partitioning into CCl(4). These effects only partially offset other types of intramolecular interactions and peptide-solvent polar interactions that are more favorable in water, leading to net transfer free energies (3-7 kcal/mol) that disfavor peptide transfer from water into carbon tetrachloride.
Collapse
Affiliation(s)
- Tian-Xiang Xiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536, USA
| | | |
Collapse
|
15
|
Ulander J, Haymet ADJ. Permeation across hydrated DPPC lipid bilayers: simulation of the titrable amphiphilic drug valproic acid. Biophys J 2004; 85:3475-84. [PMID: 14645043 PMCID: PMC1303655 DOI: 10.1016/s0006-3495(03)74768-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Valproic acid is a short branched fatty acid used as an anticonvulsant drug whose therapeutic action has been proposed to arise from membrane-disordering properties. Static and kinetic properties of valproic acid interacting with fully hydrated dipalmitoyl phosphatidylcholine lipid bilayers are studied using molecular-dynamics simulations. We calculate spatially resolved free energy profiles and local diffusion coefficients using the distance between the bilayer and valproic acid respective centers-of-mass along the bilayer normal as reaction coordinate. To investigate the pH dependence, we calculate profiles for the neutral valproic acid as well as its water-soluble anionic conjugate base valproate. The local diffusion constants for valproate/valproic acid along the bilayer normal are found to be approximately 10(-6) to 10(-5) cm2 s(-1). Assuming protonation of valproic acid upon association with--or insertion into--the lipid bilayer, we calculate the permeation coefficient to be approximately 2.0 10(-3) cm s(-1), consistent with recent experimental estimates of fast fatty acid transport. The ability of the lipid bilayer to sustain local defects such as water intrusions stresses the importance of going beyond mean field and taking into account correlation effects in theoretical descriptions of bilayer translocation processes.
Collapse
Affiliation(s)
- Johan Ulander
- Department of Biochemistry and Chemistry, University of California at San Diego, La Jolla, California, USA.
| | | |
Collapse
|
16
|
Bemporad D, Luttmann C, Essex JW. Computer simulation of small molecule permeation across a lipid bilayer: dependence on bilayer properties and solute volume, size, and cross-sectional area. Biophys J 2004; 87:1-13. [PMID: 15240439 PMCID: PMC1304332 DOI: 10.1529/biophysj.103.030601] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2003] [Accepted: 02/04/2004] [Indexed: 11/18/2022] Open
Abstract
Cell membrane permeation is required for most drugs to reach their biological target, and understanding this process is therefore crucial for rational drug design. Recent molecular dynamics simulations have studied the permeation of eight small molecules through a phospholipid bilayer. Unlike experiments, atomistic simulations allow the direct calculation of diffusion and partition coefficients of solutes at different depths inside a lipid membrane. Further analyses of the simulations suggest that solute diffusion is less size-dependent and solute partitioning more size-dependent than was commonly thought.
Collapse
Affiliation(s)
- D Bemporad
- School of Chemistry, University of Southampton, Highfield, Southampton, United Kingdom
| | | | | |
Collapse
|
17
|
Bemporad D, Essex JW, Luttmann C. Permeation of Small Molecules through a Lipid Bilayer: A Computer Simulation Study. J Phys Chem B 2004. [DOI: 10.1021/jp035260s] [Citation(s) in RCA: 225] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
18
|
Kueltzo LA, Middaugh CR. Nonclassical transport proteins and peptides: an alternative to classical macromolecule delivery systems. J Pharm Sci 2003; 92:1754-72. [PMID: 12949995 DOI: 10.1002/jps.10448] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The number of peptides and proteins known to exhibit nonclassical transport activity has increased significantly in recent years. In most cases, these entities have been studied in relation to their ability to deliver high molecular weight compounds, including proteins and DNA, for the ultimate purpose of developing new drug delivery strategies. In this review, an overview of the various types of vectors is presented. The in vitro and in vivo delivery successes of this technology, as well as preliminary therapeutic efforts, are described. Although a comprehensive mechanism of nonclassical transport has not yet been clearly established, we propose a straightforward model based on the cationic nature of the vectors and the need for lack of highly organized structure. In this hypothesis we suggest that the movement of polycations is mediated by a network of extra- and intracellular polyanions while transport across the bilayer is facilitated by cation-pi interactions between the vectors' basic groups and aromatic amino acid side chains in the bilayer spanning helices of membrane proteins.
Collapse
Affiliation(s)
- Lisa A Kueltzo
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave., Lawrence, Kansas 66047, USA
| | | |
Collapse
|
19
|
Xiang TX, Anderson BD. A computer simulation of functional group contributions to free energy in water and a DPPC lipid bilayer. Biophys J 2002; 82:2052-66. [PMID: 11916862 PMCID: PMC1302000 DOI: 10.1016/s0006-3495(02)75553-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A series of all-atom molecular dynamics simulations has been performed to evaluate the contributions of various functional groups to the free energy of solvation in water and a dipalmitoylphospatidylcholine lipid bilayer membrane and to the free energies of solute transfer (Delta(DeltaG(o))X) from water into the ordered-chain interior of the bilayer. Free energies for mutations of the alpha-H atom in p-toluic acid to six different substituents (-CH3, -Cl, -OCH3, -CN, -OH, -COOH) were calculated by a combined thermodynamic integration and perturbation method and compared to literature results from vapor pressure measurements, partition coefficients, and membrane transport experiments. Convergence of the calculated free energies was indicated by substantial declines in standard deviations for the calculated free energies with increased simulation length, by the independence of the ensemble-averaged Boltzmann factors to simulation length, and the weak dependence of hysteresis effects on simulation length over two different simulation lengths and starting from different initial configurations. Calculated values of Delta(DeltaG(o))X correlate linearly with corresponding values obtained from lipid bilayer transport experiments with a slope of 1.1 and from measurements of partition coefficients between water and hexadecane or decadiene, with slopes of 1.1 and 0.9, respectively. Van der Waals interactions between the functional group of interest and the acyl chains in the ordered chain region account for more than 95% of the overall potential energy of interaction. These results support the view that the ordered chain region within the bilayer interior is the barrier domain for transport and that solvation interactions within this region resemble those occurring in a nonpolar hydrocarbon.
Collapse
Affiliation(s)
- Tian-xiang Xiang
- Division of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, USA
| | | |
Collapse
|
20
|
Lagerquist C, Beigi F, Karlén A, Lennernäs H, Lundahl P. Effects of cholesterol and model transmembrane proteins on drug partitioning into lipid bilayers as analysed by immobilized-liposome chromatography. J Pharm Pharmacol 2001; 53:1477-87. [PMID: 11732750 DOI: 10.1211/0022357011778016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We have analysed how cholesterol and transmembrane proteins in phospholipid bilayers modulate drug partitioning into the bilayers. For this purpose we determined the chromatographic retention of drugs on liposomes or proteoliposomes entrapped in gel beads. The drug retention per phospholipid amount (the capacity factor Ks) reflects the drug partitioning. Cholesterol in the bilayers decreased the Ks value and hence the partitioning into the membrane in proportion to the cholesterol fraction. On average this cholesterol effect decreased with increasing temperature. Model transmembrane proteins, the glucose transporter GLUT1 and bacteriorhodopsin, interacted electrostatically with charged drugs to increase or decrease the drug partitioning into the bilayers. Bacteriorhodopsin proteoliposomes containing cholesterol combined the effects of the protein and the cholesterol and approached the partitioning properties of red blood cell membranes. For positively charged drugs the correlation between calculated intestinal permeability and log Ks was fair for both liposomes and bacteriorhodopsin-cholesterol proteoliposomes. Detailed modeling of solute partitioning into biological membranes may require an extensive knowledge of their structures.
Collapse
Affiliation(s)
- C Lagerquist
- Department of Biochemistry, Uppsala Biomedical Center, Uppsala University, Sweden
| | | | | | | | | |
Collapse
|
21
|
Mayer PT, Xiang TX, Anderson BD. Independence of substituent contributions to the transport of small molecule permeants in lipid bilayers. AAPS PHARMSCI 2000; 2:E14. [PMID: 11741230 PMCID: PMC2751028 DOI: 10.1208/ps020214] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To explore the independence of functional group contributions to permeability of nonelectrolytes across egg lecithin bilayers, the transport rates were measured of a series of alpha-substituted p-methylhippuric acids (-H, -Cl, -OCH3, -CN, -OH, -COOH, and -CONH2) across egg lecithin lipid bilayers, in the form of large unilamellar vesicles (LUVs) at 25 degrees C. Intrinsic permeability coefficients (P(HA)) were calculated from apparent permeability coefficients (P(app)) measured as a function of pH. Group contributions to the free energy of transfer from water into the barrier domain Delta (Delta G degrees)P,X, were calculated for the substituents and compared to the contributions of these groups when attached top-toluic acid measured earlier. The Delta (Delta G degrees)P,X values from permeability data were also correlated with Delta (Delta G degrees)PC,X values of partitioning from water into organic solvents to determine the physicochemical selectivity of the barrier domain. P(app) values in LUVs were found to vary approximately linearly with the fraction of neutral permeant over a pH range of 5.5 to 10.5, suggesting that the transport of the ionized species is negligible over this pH range. The Delta (Delta G degrees)P,X values from the 2 series of compounds appear to be the same, indicating that the functional group contributions are independent. 1,9-decadiene was found to be the most similar to the chemical environment of the barrier domain. Functional group contributions to transport across egg lecithin bilayers appear to be independent of the compound to which they are attached, even though the thickness of the barrier domain in lipid bilayers is approximately the same as the extended length of the permeant.
Collapse
Affiliation(s)
- Peter T. Mayer
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 84112 Salt Lake City, Utah USA
| | - Tian-Xiang Xiang
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 84112 Salt Lake City, Utah USA
| | - Bradley D. Anderson
- Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, 84112 Salt Lake City, Utah USA
| |
Collapse
|