Dextran-poly -water system

MET Mete, D., Goksel, C., and Gilner, A., Characterization and miscibility dynamics of dextran-poly(vinylpyiTolidone)-water system, Macra/wo/. Symp., 302, 257,2011. 

FOR Forciniti, D., Hall, C.K., and Kula, M.R., Interfacial tension of poly(etltylene glycol)-dextran-water systems influence of temperature and polymer molecular weight,/. BiotechnoL, 16, 279, 1990. 

FUR Furuya, T., Iwai, Y., Tanaka, Y., Uchida, H., Yamada, S., and Aral, Y., Measurement and correlation of Uquid-liquid equilibria for dextran-poly(ethylene glycol)-water aqueous two-phase systems at 20°C, Fluid Phase Equil., 103, 119, 1995. 

Thus, for a typical case of van der Waals interactions, when the interaction parameter Kj(T) varies as 1/T, the critical temperature should be roughly proportional to the molecular weight. However, for water-soluble jpolymers, such as the dextran-poly(ethylene glycol)-water system ° currently used in purification of biological macromolecules, the monomer-morwmer interaction parameter Ki depends on T in a more complex way > and Tk should not be simply proportional to Af and Eq. (50) may be then used to find the mass dependence of... 

Amphiphilic poly(ethylene glycol)-alkyl dextran ethers are emerging as vehicles in the oral delivery of poorly water soluble drugs [251,268,269]. They form polymer micelles of low critical association concentrations (CAC) and small micelle sizes in aqueous solution. Particulate delivery systems lead to an enhancement of the absorption efficiency and bioavailability of highly hpophihc drugs orally applied, and provide the drug with some level of pro-... 

As an example of a correlation of ternary LLE data, the system water-dextran (Mn = 23,000)-poly(ethylene glycol) (Mw = 6,750) at 273 K (Albertsson, 1986) was correlated... 

Poly(amino acid)s (PAAs) have also been used in drug delivery PEO-(l-aspartic acid) block copolymer nano-associates , formed by dialysis from a dimethyl acetamide solution against water, could be loaded with vasopressin. PLA-(L-lysine) block copolymer microcapsules loaded with fluorescently labelled (FITC) dextran showed release profiles dependent on amino acid content. In a nice study, poly(glutamate(OMe)-sarcosine) block copolymer particles were surface-grafted with poly(A-isopropyl acrylamide) (PNIPAAm) to produce a thermally responsive delivery system FITC-dextran release was faster below the lower critical solution temperature (LCST) than above it. PAAs are prepared by ring-opening polymerisation of A-carboxyanhydride amino acid derivatives, as shown in Scheme 1. 

A recent study has explored the potential of the ternary complex formed between a poly(p-cyclodextrin) (formed by polycondensation of p-cyclodextrin), a cationic surfactant (dodecyltrimethylammonium chloride), and a polyanion in water, to act as a delivery system for gene therapy,using a combination of viscometric and SANS studies as well as visual observations to determine the macroscopic and microscopic properties of the complexes. In the study, sodium dextran sulfate was used as a substitute for DNA. The potential advantages of the use of such ternary complexes over the more commonly investigated DNA-lipid or polymer complexes (lipoplexes and poly-plexes, respectively) include a high water solubility of the resulting complex (lipoplexes and polyplexes often... 

Systems with two aqueous phases have been used in the separation of proteins and metal ions.46 These involve water-soluble polymers, such as poly (ethylene glycol), with or without salts, such as potassium phosphate.47 Such systems eliminate the need for volatile organic solvents. A typical example is the separation of myoglobin with aqueous poly(/V-vinylacetamide)-dextran, the protein going to the bottom phase containing the dextran.48... 

The well documented phenomenon of separation of an aqueous solution of two different water-soluble polymers into individual phases, during recent years, has shown widespread potential in biotechnology (1). A number of polymers have been employed for the preparation of these bi-phasic systems. (2). The n st commonly used systems have been those of poly(ethylene glycol) (PEG) and dextran. The molecular weight of the polymers used plays an important role in determining the characteristics of the phase system. Phase systems formed by mixing one polymer and a high concentration of certain salts in aqueous solutions, have also been reported. (2). 

Separation by partition between two immiscible aqueous phases has been successfully applied to a large number of proteins, nucleic acids, and cellular particles such as mitochondria, chloroplasts, membrane vesicles, and whole cells. The phase systems are made up of two different water-soluble polymers, dextran and poly(ethylene glycol), dissolved in water and complemented with suitable buffers, salts, and sucrose. Highly selective adjustment of the distribution process is possible by linking an affinity... 

Additional data for the system poly(ethylene glycol) (B) -1- water (A) -1- dextran (C) can be ... 

SJO Sjoberg, A. and Karlstrom, G., Temperatrrre dependence of phase equihbria for the system poly(ethylene glycol)/dextran/water. A theoretical and experimental study. Macromolecules, 22, 1325, 1989. 

CON Connemann, M., Gaube, J., Leffrang, U., Muller, S., and Pfennig, A., Phase equilibria in the system poly(ethylene glycol) + dextran + water, J. Chem. Eng. Data, 36, 446, 1991. 

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