Poly ethylene glycol cholesterol

Beugin S, et al. New sterically stabilized vesicles based on nonionic surfactant, cholesterol, and poly(ethylene glycol)-cholesterol conjugates. Biophys J 1998 74 3198. 

Development of sterically stabilized liposomes (SSL) composed of high Tm lipids, cholesterol, and a lipopolymer, such as poly-(ethylene glycol methyl ether)-l,2-distearoyl-i n-glycero-3-phospho-ethanolamine triethyl ammonium salt (1,3-5,8,9,14,15)... 

Maruyama K, Yuda T, Okamoto A, et al. Prolonged circulation time in vivo of large unilamelar liposomes composed of distearoyl phosphatidylcholine and cholesterol containing amphipathic poly(ethylene glycol). Biochim Biophys Acta 1992 1128 44. 

Figure 2 Encapsulation as a function of ethanol concentration. Oligonucleotides were added to distearoyl-phosphatidyl-choline/cholesterol/l-0-(2 -(co-methoxy-poly-ethylene-glycol)succinoyl)-2-iV-myristoyl-sphingosine /1,2-dioleoyl-3-dimethylam-monium propane liposomes in varying concentrations of ethanol at an initial oligonucleotide-to-lipid ratio of 0.24mg/mg. Abbreviations AS, antisense oligonucleotide %EtOH(v/v), percentage of ethanol in volume/volume.

Figure 4 Effect on the serum stability of the incorporation of 5% cholesterol poly(ethy-lene glycol) (PEG) into cationic lipoplexes [hpopolyamine RPR209120/DOPE1/1, ratio (mol) lipid/DNA = 10 in 150 mM NaCl]. Lipoplexes were incubated in DMEM + 10% SVF, at 37°C, aliquots were regularly sampled and monitored by dynamic diffusion. Results represent a mean between three measurements. Error bars are not presented to simplify the graph, but differences among PEG, PEG-1, and PEG-2 are significant. Abbreviations PEG, poly(ethylene glycol) DOPE, dioleylphosphatidylethanolamine DMEM, Dulbecco s Modified Eagle Medium.

A new polymeric amphiphile based on cationic poly(L-lysine), which was partially modified with hydrophobic palmitoyl chains and hydrophilic neutral methoxy-poly(ethylene glycol) (Fig. 7e), was introduced by Uchegbu et al. [38,39], In water in the presence of cholesterol, these copolymers assembled into vesicles with diameters ranging from 200 to 600 nm (DLS, freeze-fracture TEM), depending on the chemical composition of the copolymer and the length of the polypeptide backbone. More detailed information about the secondary structure of chains and the structure of vesicle membranes were not given. 

The optimum molecular weight of the poly(ethylene glycol) (PEG) polymer was determined to be 2000. At this weight the polymer was solid at room temperature and therefore can easily be precipitated from the reaction mixture. Alcohols such as benzoin and cholesterol were oxidised in comparable yields to those reported in the literature. 

Ahn et al. reported [62] preparation of a smetic hquid crystalline elastomer with shape memory properties. Shape memory polymeric materials can recover their equilibrium, permanent shapes from nonequilibrium, temporary shapes as a result of external stimuli, like heat or light. Such materials have apphcation in medical practice. Main-chain polynorbomenes were linked with three different side-chains, cholesterol, poly(ethylene glycol), and butylacrylate. 

Permeabilization of polymer membranes is increased by ethanol or mixtures of specific organic solvents. For example, a small amount (< 0.5% v/v) of ethanol [92] or mixtures of ethanol and dimethyl sulfoxide (1 1 v/v) [90] in the system has no influence on the membrane permeability of PMOXA-fc-PDMS-fc-PMOXA copolymers, and therefore much higher amounts of solvents are necessary to destabilize the membrane. However, this permeabilization method is not appropriate when bioapplications are intended. Likewise, a copolymer membrane based on poly(ethylene glycol)-fcZock-poly(D,L-laetic-5to/-glycolic acid) (PEG-fc-PLGA), which exhibits 18-fold less permeability to protons than a liposome membrane (based on a mixture of soybean phospholipids and cholesterol) was rendered more permeable for proton diffiision when increasing amounts of 1,4-dioxane (5-20%) were added (Fig. 11.7) [93]. Upon removal of the 1,4-dioxane by dialysis, the proton diffusion returned to... 

The OH functionality on cholesterol (Choi) can be used directly for the esterification with COOH end-functionalized polymers, by the aid of dicyclohexylcar-bodiimide (DCC) and DMAP (Scheme 14) [114]. Star-shaped and linear poly (ethylene glycol) (PEG) with terminal Cfiol entities have been prepared, and used... 

Copolymer of methoxy Doxorubicin poly[ ethylene glycol]-b-poly[Ai-2-hydroxypropyl methacrylamide-co-histidinej -cholesterol CmPEG-P(HPMA-g-His)-cholesterol) cross-linked with biotin-polyethylene glycol-biotin (biotin2-PEG)... 

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