@article {2118, title = {Unimolecular Micelles based on Hydrophobically Derivatized Hyperbranched Polyglycerols: Biodistribution Studies}, journal = {Bioconjugate Chemistry}, volume = {19}, number = {11}, year = {2008}, note = {ISI Document Delivery No.: 373VOTimes Cited: 7Cited Reference Count: 31Kainthan, Rajesh Kumar Brooks, Donald E.}, month = {Nov}, pages = {2231-2238}, type = {Article}, abstract = {We recently reported the synthesis and testing of a new class of unimolecular micelles based on hyperbranched polyglycerols as second generation synthetic plasma expanders and as general drug delivery vehicles. A detailed biodistribution study of two derivatized hyperbranched polyglycerols of different molecular weights derivatized with hydrophobic groups and short poly(ethylene glycol) chains is reported in this article. In mice, these materials are nontoxic with circulation half-lives as high as 31 h, controllable by manipulating the molecular weight and the degree of PEG derivatization. Organ accumulation is low, presumably due to the "pegylation" effect. Thermal degradation and hydrolysis data suggest that these polymers are highly stable with a long shelf life, a major advantage for a pharmaceutical product. Degradation under acidic conditions has been observed for these polymers.}, keywords = {ALBUMIN, BIOLOGICAL EVALUATION, DENDRIMERS, IMMUNOGENICITY, IN-VIVO, LIPOSOMES, MOLECULAR-WEIGHT, POLYETHYLENE-GLYCOL DEGRADATION, POLYMERS, STARCH}, isbn = {1043-1802}, url = {://000261001800018}, author = {Kainthan, R. K. and Brooks, D. E.} } @article {935, title = {Stereochemical assignment in acyclic lipids across long distance by circular dichroism: Absolute stereochemistry of the aglycone of caminoside A}, journal = {Angewandte Chemie-International Edition}, volume = {43}, number = {44}, year = {2004}, note = {ISI Document Delivery No.: 874FTTimes Cited: 14Cited Reference Count: 30}, pages = {5946-5951}, type = {Article}, keywords = {AGENT, ANTIVIRAL ANTIBIOTICS, B-1, CHROMOPHORES, circular dichroism, CONFIGURATION ANALYSIS, CYCLOVIRACIN, glycolipids, LIPOSOMES, MOSHER METHOD, natural products, NMR, PHYSICOCHEMICAL, PROPERTIES, SECONDARY ALCOHOLS, SPIN-COUPLING CONSTANTS, STEREOCHEMISTRY}, isbn = {1433-7851}, url = {://000225337000017}, author = {MacMillan, J. B. and Linington, R. G. and Andersen, R. J. and Molinski, T. F.} } @article {597, title = {Drug release characteristics of lipid based benzoporphyrin derivative}, journal = {Journal of Pharmacy and Pharmaceutical Sciences}, volume = {6}, number = {1}, year = {2003}, note = {ISI Document Delivery No.: 679QJTimes Cited: 21Cited Reference Count: 17}, month = {Jan-Apr}, pages = {13-19}, type = {Article}, abstract = {PURPOSE. The purpose of this study was to examine the transfer of verteporfin (BPDMA) from its lipid based formulation to serum proteins. METHODS. As a result of BPDMA being confined to the lipid phase, it was found that fluorescence from the photosensitizer was highly concentration quenched. This phenomenon was used to demonstrate rapid transfer of lipid-based drug to various plasma components such as albumin and lipoproteins. Gel electrophoresis was used to show transfer of drug to lipoproteins. RESULTS. Loss of fluorescence quenching showed rapid transfer of the drug from its lipid based formulation to serum proteins. Gel electrophoresis showed that both the drug and phospholipid components were transferred to the lipoprotein fraction concurrently. The electrophoretic mobility of plasma lipoproteins was increased as a result of their interaction with lipid-based BPDMA. It was also shown that the lipid-based structures were readily destabilized in the presence of relatively low concentrations of plasma, and that liposomes of this lipid composition were highly unlikely to be found intact in the circulation following intravenous injection. CONCLUSIONS. Verteporfin is rapidly transferred from its lipid based formulation to serum proteins. This rapid transfer, particularly to lipoproteins, provides a mechanism for its rapid delivery to cells.}, keywords = {DENSITY LIPOPROTEINS, DESTABILIZATION, LIPOSOMES, PHOTODYNAMIC THERAPY, PLASMA-LIPOPROTEINS, PROTEIN, TUMORS}, isbn = {1482-1826}, url = {://000182933200002}, author = {Chowdhary, R. K. and Shariff, I. and Dolphin, D.} } @article {4703, title = {Electrostatically mediated interactions between cationic lipid-DNA particles and an anionic surface}, journal = {Archives of Biochemistry and Biophysics}, volume = {366}, number = {1}, year = {1999}, note = {ISI Document Delivery No.: 202JKTimes Cited: 7Cited Reference Count: 29}, month = {Jun}, pages = {31-39}, type = {Article}, abstract = {In an effort to model the interaction of lipid-based DNA delivery systems with anionic surfaces, such as a cell membrane, we have utilized microelectrophoresis to characterize how electrokinetic measurements can provide information on surface charge and binding characteristics. We have established that cationic lipids, specifically N-N-dioleoyl-N,N-dimethylammonium chloride (DODAC), incorporated into liposomes prepared with I,2-dioleoyl-i-glycero-3-phosphoethanolamine (DOPE) or 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) at 50 mol\%, change the inherent electrophoretic mobility of anionic latex polystyrene beads. Self-assembling lipid-DNA particles (LDPs), prepared at various cationic lipid to negative DNA phosphate charge ratios, effected no changes in bead mobility when the LDP charge ratio (+/-) was equal to or less than 1. Increasing the LDP concentration in a solution of 0.1\% (w/v) anionic beads resulted in a charge reversal effect when a net charge of LDP to total bead charge ratio (+/-) of 1:1 was observed. LDP formulations, utilizing either DOPE or DOPC, showed similar titration profiles with a charge reversal observed at a 1:1 net LDP to bead charge ratio (+/-). It was confirmed through centrifugation studies that the DNA in the LDP was associated with the anionic latex beads through electrostatic interactions. LDP binding, rather than the binding of dissociated cationic lipids, resulted in the observed electrophoretic mobility changes of the anionic latex beads. (C) 1999 Academic Press.}, keywords = {BILAYERS, CELLS, ELECTROSTATIC INTERACTIONS, FUSION, GENE-TRANSFER, lipid-DNA particles, lipoplex, LIPOSOMES, microelectrophoresis, PHOSPHATIDYLETHANOLAMINE, PLASMID DNA, VESICLES}, isbn = {0003-9861}, url = {://000080648400005}, author = {Wong, F. M. P. and Bally, M. B. and Brooks, D. E.} } @article {4346, title = {Equations describing passive transport through vesicular membranes}, journal = {Biophysical Chemistry}, volume = {70}, number = {1}, year = {1998}, note = {ISI Document Delivery No.: YU539Times Cited: 4Cited Reference Count: 26}, month = {Jan}, pages = {65-74}, type = {Article}, abstract = {A theoretical description of the kinetics of the passive transport of both lipophobic and lipophilic nonelectrolytes, weak acids, and weak bases through membranes of large unilamellar vesicles is discussed. Equations are derived which may be used to obtain permeability coefficients and predict the extent of LW entrapment of permeant molecules. Theoretical curves are generated to illustrate the difference between lipophobic and lipophilic permeation. By applying a diffusional approach rather than a simple first order kinetic approach to the problem of passive transport, some of the inconsistencies observed in other works are corrected. (C) 1998 Elsevier Science B.V.}, keywords = {accumulation, DIFFUSION, FATTY-ACIDS, IONS, KINETICS, LARGE UNILAMELLAR VESICLES, lipid bilayer, LIPID BILAYER-MEMBRANES, LIPOSOMES, PARTITION-COEFFICIENTS, passive, permeability, PROCEDURE, RAPID EXTRUSION, TRANSMEMBRANE PH GRADIENTS, TRANSPORT}, isbn = {0301-4622}, url = {://000071728000007}, author = {Males, R. G. and Phillips, P. S. and Herring, F. G.} } @article {4210, title = {Inhibition of liposome-induced complement activation by incorporated poly(ethylene glycol) lipids}, journal = {Archives of Biochemistry and Biophysics}, volume = {357}, number = {2}, year = {1998}, note = {ISI Document Delivery No.: 119UCTimes Cited: 65Cited Reference Count: 50}, month = {Sep}, pages = {185-194}, type = {Article}, abstract = {Complement activation causes opsonization of foreign particles leading to particle elimination from the blood. Complement-mediated opsonization of charged and large liposomes presents a fundamental problem in their use to deliver therapeutic agents in vivo. To prolong the circulation half-lives of such liposomes, complement activation must be curtailed. The aim of this study was to assess the ability of poly(ethylene glycol)-lipids (PEG-lipids) to inhibit the in vitro activation of the classical pathway of complement in human serum by anionic liposomes. Incorporation of cholesterol-PEG(600) (CH-PEG(600)), cholesterol-PEG(1000) (CH-PEG(1000)), or phosphatidylethanolamine-PEG(2000) (PE-PEG(2000)) resulted in dose-dependent inhibition of Clq binding and complement activation. The dose of PEG-lipid at which complement activation was blocked was inversely related to the PEG chain length. Complement activation was strongly inhibited when 15 mole\% of CH-PEG(600), 10 mole\% CH-PEG(1000), or 5 mole\% PE-PEG(2000), was incorporated into 100-nm anionic liposomes. PEG-lipid incorporation into larger liposomes (240 nm) was also successful in blocking C1q binding and complement activation. Radiolabeled cholesterol-PEG(similar to 1400) was prepared and used to determine both the percentage of CH-PEG incorporated into the liposomes and the percentage maintained in the liposomes in the presence of 50\% human serum at 37 degrees C for up to 24 h. (C) 1998 Academic Press.}, keywords = {C1q, CHOLESTEROL, CLEARANCE, complement activation, HEPATIC-UPTAKE, INVIVO, LARGE UNILAMELLAR VESICLES, LIPOSOMES, POLY(ETHYLENE GLYCOL), POLYETHYLENE-GLYCOL, PROLONGED CIRCULATION TIME, SERUM, SIZE, SURFACE-CHARGE}, isbn = {0003-9861}, url = {://000075915200002}, author = {Bradley, A. J. and Devine, D. V. and Ansell, S. M. and Janzen, J. and Brooks, D. E.} } @article {3938, title = {The effect of organotin compounds on the permeability of model biological membranes}, journal = {Applied Organometallic Chemistry}, volume = {11}, number = {5}, year = {1997}, note = {ISI Document Delivery No.: WZ733Times Cited: 7Cited Reference Count: 28Pacifichem 95 Meeting on Safety and Environmental Effects of Organometallics1995HONOLULU, HI}, month = {May}, pages = {369-379}, type = {Proceedings Paper}, abstract = {The efflux of dimethylarsinic acid (DMA) from liposomes formed from egg phosphatidylcholine (EPC) is increased when tributyltin chloride (TBT) is added to the extraliposomal compartment; however the addition of monobutyltin trichloride (MBT) slows down the efflux. When the liposomes are prepared from EPC and organotin compounds, different mechanisms for DMA efflux seem to operate: TBT-EPC liposomes show a mixture of facilitated and passive diffusion; MBT-EPC liposomes show only passive diffusion. The facilitated diffusion of DMA(-) seems to be stopped by the addition of TBT to the extraliposomal compartment. (C) 1997 by John Wiley \& Sons, Ltd.}, keywords = {bilayer, DIMETHYLARSINIC ACID, efflux, egg, ERYTHROCYTE, EXCHANGE, facilitated diffusion, LIPOSOMES, membrane modification, monobutyltin, NMR, PHOSPHATIDYLCHOLINE, tributyltin chloride, trichloride}, isbn = {0268-2605}, url = {://A1997WZ73300003}, author = {Cullen, W. R. and Herring, F. G. and Nwata, B. U.} } @article {3838, title = {Poly(ethylene glycol) amphiphile adsorption and liposome partition}, journal = {Journal of Chromatography B-Biomedical Applications}, volume = {680}, number = {1-2}, year = {1996}, note = {ISI Document Delivery No.: UQ821Times Cited: 4Cited Reference Count: 649th International Conference on Partitioning in Aqueous 2-Phase Systems - Advances in the Use of Polymers in Cell Biology, Biotechnology and Environmental SciencesJUN 04-09, 1995ZARAGOZA, SPAIN}, month = {May}, pages = {145-155}, type = {Proceedings Paper}, abstract = {Surface localized poly(ethylene glycol) (PEG) amphiphiles of type C-16:0-EO(151) and C-18:2-EO(1.51) were studied via ellipsometry at macroscopic, hat methylated silica (MeSi), phosphatidic acid (PA), and phosphatidylcholine (PC) surfaces. At these surfaces the amphiphiles adsorb similarly, in a non-cooperative manner, achieving a plateau (approximate to 0.1 PEG chains/nm(2)) well below amphiphile critical micelle concentration (CMC). The resultant PEG-enriched layers were 10-15 nm thick, with a polymer concentration (approximate to 0.07 g/cm(3)) greater than the PEG-enriched phase of many dextran, PEG aqueous two-phase systems. PEG-amphiphile adsorption (mg/m(2)) at hydrophobic and phospholipid flat surfaces correlated with changes in the partition (log K) of PC liposomes in such two-phase systems. PEG-amphiphile adsorption at macroscopic surfaces appears to represent a balance between hydrophobic attraction and repulsive intra-chain interactions which promote chain elongation normal to the surface.}, keywords = {ADSORPTION, AQUEOUS 2-PHASE SYSTEMS, BEHAVIOR, CELL-SEPARATION, critical micelle concentration, ellipsometry, HYDROPHOBIC AFFINITY PARTITION, LIPOSOMES, partitioning, PHASE SYSTEMS, poly(ethylene glycol) (PEG), polymer, PROTEINS, SURFACE-PROPERTIES, WATER-INTERFACE}, isbn = {0378-4347}, url = {://A1996UQ82100016}, author = {VanAlstine, J. M. and Malmsten, M. and Brooks, D. E.} } @article {7204, title = {THE USE OF LIPOSOMES IN PREDICTING THE BIOLOGICAL MOBILITY OF ARSENIC COMPOUNDS}, journal = {Applied Organometallic Chemistry}, volume = {6}, number = {2}, year = {1992}, note = {ISI Document Delivery No.: HQ168Times Cited: 10Cited Reference Count: 14INTERNATIONAL CONF ON ENVIRONMENTAL AND BIOLOGICAL ASPECTS OF MAIN-GROUP ORGANOMETALS ( ICEBAMO )SEP 15-19, 1991PADUA, ITALYUNIV PADUA, ITALIAN CHEM SOC}, month = {Apr}, pages = {179-183}, type = {Proceedings Paper}, abstract = {Efflux studies of radio-labelled methylarsonic acid (MMA) and dimethylarsinic acid (DMA) encapsulated in liposomes afford the following permeability values for the two arsenicals: 1.4 x 10(-13) cm s-1 and 4.5 x 10(-11) cm s-1 for MMA and DMA, respectively. These data are compared with the octanol/water partition coefficients which are 7.4 x 10(-3) and 8.4 x 10(-3) for MMA and DMA, respectively.}, keywords = {DIFFUSION, LIPOSOMES, MEMBRANE, ORGANOARSENIC}, isbn = {0268-2605}, url = {://A1992HQ16800010}, author = {Cullen, W. R. and Nelson, J.} }