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Topic: Amphiphilic


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In the News (Wed 22 May 19)

  
  United States Patent Application: 0040091546
Amphiphilic copolymers and the additive target molecules can be mixed in a ratio between about 1:20 to about 20:1 by weight and result in nanoparticles of amphiphilic copolymers with additive target molecule.
The amphiphilic copolymers used in this invention are comprised of blocks of at least two sub-units or with a minimum contour length the equivalent of at least 5 ethylene units and of a given character and a molecular weight of at least 300 g/mole.
In the present case, nanoparticle compositions in which amphiphilic copolymers contain PEO as the water soluble component are used for steric stabilization of a target molecule are desirable to obtain the properties for a pharmaceutical formulation.
appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=20040091546&OS=20040091546&RS=20040091546   (15321 words)

  
 Patent 6,814,971
The invention relates to adjuvants that contain a lecithin, an oil and an amphiphilic surfactant and that are capable of forming a stable oil-in-water emulsion vaccine so as to minimize local reactions to the vaccine in the injected animal.
In another preferred embodiment, two amphiphilic surfactants are used in an adjuvant of the invention, for example a Tween and a Span surfactant.
Amphiphilic surfactants useful in the adjuvant of the invention have HLB values from about 2 to about 20, preferably from about 3 to about 17.
www.pharmcast.com /Patents100/Yr2004/Nov2004/110904/6814971_Adjuvants110904.htm   (3671 words)

  
 Amphiphilic self-assembly   (Site not responding. Last check: 2007-10-08)
Amphiphiles like tensids or lipids are small molecules which have both hydrophilic and hydrophobic parts and self-assemble in polar solvents like water, non-polar solvents like oil or at the interfaces of polar and non-polar regions of space.
Amphiphilic systems exhibit, in general, an amazing degree of polymorphism due to the very small differences in free energy between the various structures possible.
In ternary systems of amphiphile, water and oil, the same phases exist as in the binary systems, only that now the hydrophobic regions are filled with oil.
www.mpikg-golm.mpg.de /theory/people/schwarz/amphiphiles.html   (751 words)

  
 Lipid -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-08)
Another part of their structure is polar or (additional info and facts about hydrophilic) hydrophilic ("water-loving") and will tend to associate with polar solvents like water.
In the case of (An animal sterol that is normally synthesized by the liver; the most abundant steroid in animal tissues) cholesterol, the polar group is a mere -OH ((The monovalent group -OH in such compounds as bases and some acids and alcohols) hydroxyl or alcohol).
Micelles form when single-tailed amphiphilic lipids are placed in a polar milieu, while lipid bilayers form when two-tailed phospholipids are placed in a polar environment (Fig.
www.absoluteastronomy.com /encyclopedia/l/li/lipid.htm   (728 words)

  
 Origin of Life   (Site not responding. Last check: 2007-10-08)
Amphiphilic molecules have one end that favourably interacts with water molecules (hydrophilic) and another that is far less interactive (hydrophobic).
The amphiphilic molecules on the primitive earth have undeniably undergone considerable evolution as the first forms of life emerged and acquired new catalytic capacities.
Although viewed to have primarily structural roles, amphiphilic molecules and their ability to spontaneously form membranous microenvironments definitely underlie some of the earliest key events that led to the emergence of biological complexity.
www.bioteach.ubc.ca /Biodiversity/origin   (1878 words)

  
 amphiphilic networks   (Site not responding. Last check: 2007-10-08)
Description: An amphiphilic network is a random cocontinuous assemblage of hydrophilic and hydrophobic chains that is able to swell in both water and hydrocarbons.
Thus, amphiphilic networks are able to change their conformations (morphologies) depending on the medium of solution they are exposed to.
Amphiphilic polymers exhibit the property of dissolving or swelling in both aqueous and organic media and are of great interest and use in cosmetic, pharmaceutical, detergent, coating and oil recovery industries.
www.temarex.com /amphi.htm   (266 words)

  
 Bicontinuous Cubic Phases in Amphiphilic Systems   (Site not responding. Last check: 2007-10-08)
Amphiphilic molecules have both polar and non-polar parts (eg a polar headgroup connected to a hydrocarbon chain).
We speak of binary amphiphilic systems if the amphiphile is mixed with a polar or a non-polar solvent like water or oil; and of ternary amphiphilic systems if the amphiphile is mixed with both a polar and a non-polar solvent.
One of the intriguing aspects of amphiphilic polymorphism is the existence of bicontinuous phases which can be traversed in any direction in both the hydrophilic (water-like) and the hydophobic (oil-like) regions.
www.mpikg-golm.mpg.de /theory/people/schwarz/BicontinuousPhases   (1322 words)

  
 HPC-Europa Report by Nélido González-Segredo
Amphiphilic fluids can be considered to be paradigm systems for the study of the interplay between morphogenic attraction-repulsion intermolecular interactions and the hydrodynamics of the fluid medium.
Gyroid liquid-crystal amphiphilic mesophase (c), as self-assembled by Lattice-Boltzmann simulations [7] from a random, homogeneous mixture of two immiscible fluids plus a surfactant species in high concentration.
The lines abovementioned were: (1.) fluid flow through an amphiphilic mesophase grafted in a microchannel, (2.) shearing of amphiphilic mesophases, (3) finishing the implementation of a LB algorithm for amphiphilic fluid flow, and (4) testing and adapting a serial colloidal-flow computer code.
www.hlrs.de /hpc-europa/GUESTS/NELIDO_GONZALEZ-SEGREDO   (1869 words)

  
 National Synchrotron Light Source
In order to generate vectorial function across an interface, we have investigated two approaches that are designed to render the 4-helix bundles themselves amphiphilic such that they possess both a hydrophilic and a hydrophobic domain along the length of each bundle.
The vectorial orientation of the 4-helix bundles in a two-dimensional ensemble at an interface between polar and non-polar media should then allow large second-order non-linear optical phenomena to be generated at the interface.
These two new types of amphiphilic 4-helix bundles now allow for the positioning of prosthetic groups on either side or both sides of the interface.
www.nsls.bnl.gov /newsroom/science/2004/11-Blasie.htm   (965 words)

  
 Amphiphilic Star-Like Macromolecules as Novel Carriers for Topical Delivery of Nonsteroidal Anti-Inflammatory Drugs
In contrast to conventional polymeric micelles, which consist of thermodynamic aggregates of amphiphilic molecules (eg, Pluronic P-85), amphiphilic star-like macromolecules (ASMs) have hydrophilic and hydrophobic segments that are covalently connected.
Thus, the micelle structure is static rather then dynamic and maintained at all concentrations and in a variety of solvents.
The hydrophobic core serves as a reservoir for an insoluble drug, whereas the hydrophilic shell composed of PEG is responsible for micelle stabilization, aqueous solubility, and interactions with plasmatic proteins and cell membranes.
www.aapspharmsci.org /view.asp?art=ps050426   (5273 words)

  
 Amphiphilic biopolymers (amphibiopols) as new surfactants for membrane protein solubilization -- Duval-Terrié et ...   (Site not responding. Last check: 2007-10-08)
Amphiphilic biopolymers (amphibiopols) as new surfactants for membrane protein solubilization -- Duval-Terrié et al.
Eisele, J.-L. and Rosenbusch, J.P. In vitro folding and oligomerization of a membrane protein: Transition of bacterial porin from random coil to native conformation.
Porcar, I., Cottet, H., Gareil, P., and Tribet, C. Association between protein particles and long amphiphilic polymers: Effect of the polymer hydrophobicity on binding isotherms.
www.proteinscience.org /cgi/content/full/12/4/681   (4091 words)

  
 Patent 6,149,937
A process for the entrapment of amphiphilic compounds as uncharged or ionic with different mole ratios of phospholipid to the amphiphilic compound.
Preparations of ionic species of amphiphilic compounds in the absence of crystals can be prepared, while preparations of uncharged amphiphilic compounds can be prepared with the compound exclusively entrapped inside the liposomes, or partly entrapped inside the liposomes with extraliposomal crystals.
a) dissolving the apolar hydrophobic species of the amphiphilic compound in the phospholipid bilayers using predetermined phospholipid/compound mole ratios to obtain preparations of liposomes with the compound exclusively entrapped inside the liposomes without crystals of the compound, or is partly entrapped inside the liposomes with extraliposomal crystals;
www.pharmcast.com /Patents/November2000/112100OG/6149937_Liposomes112100.htm   (571 words)

  
 Reasons To Believe: Facts For Faith Issue 10, 2002
Amphiphilic compounds with a single long hydrocarbon chain generally form spherical structures, referred to as micelles (figure 5).
Formation of nonanoic acid bilayers (or bilayers comprised of any amphiphile with a single hydrocarbon chain) is as improbable as a river flowing up a mountain, since several “just right” conditions need to be met simultaneously.
Amphiphile: a molecule with a polar head attached to a long hydrophobic tail.
www.reasons.org /resources/fff/2002issue10/index.shtml   (17238 words)

  
 Drug-Induced Phospholipidosis: Are There Functional Consequences? -- Reasor and Kacew 226 (9): 825 -- Experimental ...
Amiodarone, fluoxetine, imipramine, chlorcyclizine, tamoxifen, and gentamicin are considered cationic amphiphilic (lipophilic) drugs because each has a hydrophobic region containing a substituted or unsubstituted aromatic or aliphatic ring structure and a hydrophilic region consisting of one or more primary or substituted nitrogen groups that are positively charged at physiological pH.
Fluorescence studies of the binding of amphiphilic amines with phospholipids.
Biochemical and morphologic investigation of the influence of chlorphentermine and subsequent withdrawal on newborn rat lung.
www.ebmonline.org /cgi/content/full/226/9/825   (3344 words)

  
 Molecular dynamics of amphiphilic calixarene   (Site not responding. Last check: 2007-10-08)
An amphiphilic calix[6]arene, which possesses a deep cavity, aggregates in aqueous solution by hydrophobic interaction.
The conformation of aggregated calix[6]arene is conical owing to the coordination of metal ions and hydrophobic interaction between its aromatic parts.
Amphiphilic calixarene molecules recognize each other and form oligomeric complexes in aqueous solution owing to hydrophobic interaction, and the large cavity size and deep hydrophobic cavity are important factors that allow the calixarenes to aggregate.
www.arkat-usa.org /ark/journal/2003/I08_Fukumoto/KF-771H/771H.asp   (2285 words)

  
 Materials Research Lab - "Self-Assembling Amphiphilic Peptides from Marine Bacteria and their Biological Role Mediating ...
In the absence of iron the marinobactins are present as micelles at concentrations exceeding their CMC; upon addition of iron(III), the micelles under go a phase change to form vesicles.
The only siderophores which bear a structural resemblance to the marinobactins and aquachelins are the amphiphilic mycobactin and exochelin siderophores.
These siderophores are produced by mycobacteria, such as Mycobacterium tuberculosis, the bacterium causing tuberculosis, which is the leading cause of death in the world.
www.mrl.ucsb.edu /mrl/events/seminars/show_seminar.php?key=0956790000Butler   (267 words)

  
 Lateral Organization of Lipid Membranes Induced by Amphiphilic Polymer Inclusions
Polymers belonging to a set of amphiphilic poly(acrylic acid) derivatives of varying hydrophobicity and charge density have recently been shown to slowly break small lipid vesicles and stabilize for hours or days transient mixed states such as membrane sheets, aggregates of mixed micelles, integral membrane proteins complexes, and so forth.
We used giant unilamellar vesicles labeled with fluorescent probes to observe the evolution of a whole lipid-membrane including nondisruptive events, during the polymer-induced transition.
The slow kinetics of reorganization and generic formation of domains are specific features of the macromolecules in contrast with the well-documented effects of short surfactant molecules.
pubs.acs.org /cgi-bin/abstract.cgi/langd5/2002/18/i20/abs/la025654v.html   (301 words)

  
 Synthesis and Complexation Properties of an Amphiphilic Cyclodextrin   (Site not responding. Last check: 2007-10-08)
Synthesis and Complexation Properties of an Amphiphilic Cyclodextrin
The formation of amphiphilic cyclodextrins through esterification or etherification at the secondary hydroxyl face has also been described.
[3] However most examples of amphiphilic cyclodextrins are per-6, per-2,3 or per-2,6 substituted compounds and then the inclusion properties of the cavity of cyclodextrin are partially lost due to steric hindrance for the entrance of the host.
www.arkat-usa.org /ark/journal/2001/I12_Tee/302/302.asp   (3130 words)

  
 Nanostructure of Ionic Amphiphilic Block Copolymer Monolayer at Air / Water Interface   (Site not responding. Last check: 2007-10-08)
Amphiphilic diblock copolymers,(1and2) which have hydrophilic and hydrophobic chains, self-assemble to form a monolayer at the air / water interface and a micelle in selective solvents.
Furthermore, the hydrophilic chain in the polymer monolayer is an excellent model system of the "polymer brush,"(3) which is useful in surface modification, colloid stabilization, etc.
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www.dekker.com /sdek/93729035-2528623/abstract~db=enc~content=a713557565   (280 words)

  
 (WO 01/83564) AMPHIPHILIC MACROCYCLIC DERIVATIVES AND THEIR ANALOGUES   (Site not responding. Last check: 2007-10-08)
(57) Soluble amphiphilic macrocycle analogues having lipophilic groups attached to one side of the units making up the macrocycle and hydrophilic groups attached to the other side.
These amphiphilic macrocyclic derivatives have the ability to self-assemble in aqueous solvent forming micelles or vesicles and can be used as hosts for the solubilisation and/or stabilisation of various compounds.
Embodiments of the present invention utilise macrocyclic oligosaccharides and preferably cyclodextrin as the macrocyclic derivatives to be modified.
www.wipo.int /ipdl/IPDL-CIMAGES/view/pct/getbykey5?KEY=01/83564.011108   (189 words)

  
 K+ current inhibition by amphiphilic fatty acid metabolites in rat ventricular myocytes -- Xu and Rozanski 275 (6): ...
K+ current inhibition by amphiphilic fatty acid metabolites in rat ventricular myocytes -- Xu and Rozanski 275 (6): 1660 -- AJP - Cell Physiology
purpose of the present study was to determine the impact of amphiphilic
To assess the significance of intracellular amphiphile on the overall electrophysiology of myocytes, action potentials were
ajpcell.physiology.org /cgi/content/full/275/6/C1660   (3108 words)

  
 Search Results for amphiphilic - Encyclopædia Britannica
One of the triumphs of molecular biology during the decade from 1965 to 1975 was the recognition of the cell membrane as a fluid collection of amphiphilic molecules.
Early stages in the evolutionary pathway presumably centred...
Includes illustrated information on studies in electron microscopy, polyelectrolytes, and amphiphilic block copolymers.
www.britannica.com /search?query=amphiphilic&submit=Find&source=MWTEXT   (153 words)

  
 Aggregation of Amphiphilic Molecules in Supercritical CO2   (Site not responding. Last check: 2007-10-08)
Abstract: Highly soluble amphiphilic materials are shown to form aggregates in supercritical CO The strategy for synthesis of these amphiphilic molecules involves incorporating CO -philic segments that, for this study, are perfluorinated alkyl chains.
Subsequent small angle x-ray scattering (SAXS) measurements were used to characterize the aggregation of these materials in supercritical CO Each of the three amphiphiles studies showed a different type of aggregation behavior.
The improved understanding of amphiphile aggregation in CO will aid in the development of new routes for polymer and organic synthesis in this relatively benign solvent.
www.pnl.gov /supercriticalfluid/abs6.stm   (254 words)

  
 Special Feature: Self-assembling amphiphilic molecules: Synthesis in simulated interstellar/precometary ices -- Dworkin ...
All amphiphiles have the capacity to form monolayers at air-water interfaces.
proximity to amphiphilic molecules and are captured on rehydration
To determine the amphiphilic character of the residue, we used a standard Langmuir isotherm test for surface activity.
www.pnas.org /cgi/content/full/98/3/815   (2914 words)

  
 Aggregation Behavior of Amphiphilic Phthalocyanine Block Copolymers
Novel amphiphilic poly(norbornene)s were prepared from two different monomers bearing a copper phthalocyanine and a branched hydrophilic side chain through a ring-opening metathesis reaction using a ruthenium initiator.
The phthalocyanine moieties were contained as a side chain of the resulting poly(norbornene) backbone.
The aggregation behavior of the amphiphilic phthalocyanine diblock copolymer was investigated by a monolayer experiment at a water-air interface, transmission electron microscopy (TEM), and atomic force microscopy (AFM).
pubs.acs.org /cgi-bin/abstract.cgi/langd5/2002/18/i20/abs/la020275n.html   (153 words)

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