Dextran applications

Gauwerky JF, Heinrich D, Kubh F. Complications of intraperitoneal dextran application for prevention of adhesions. Biol Res Pregnancy Perinatol 1986 7(3) 93-7. 

There are various derivatives explored by using several cross linking agents. In earlier studies methacrylated and succinic derivative of dextran wifli a methacrylated and succinic derivative of poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA), PHM-SA were prepared as mentioned in Fig. 2.6. These and many alike methodologies have revolutionize the dextran applications in diverse areas of biomedical science. 

Ragano, J.S. McCutchan, J.H.(1969).Enhancement of viral infectivity with DEAE-Dextran Application to development of vaccines. Prog. Immunobiol Standard,3,152-158. 

Sephadex. Other carbohydrate matrices such as Sephadex (based on dextran) have more uniform particle sizes. Their advantages over the celluloses include faster and more reproducible flow rates and they can be used directly without removal of fines . Sephadex, which can also be obtained in a variety of ion-exchange forms (see Table 15) consists of beads of a cross-linked dextran gel which swells in water and aqueous salt solutions. The smaller the bead size, the higher the resolution that is possible but the slower the flow rate. Typical applications of Sephadex gels are the fractionation of mixtures of polypeptides, proteins, nucleic acids, polysaccharides and for desalting solutions. 

The broad pore size distribution of Sepharose makes it well apt for the analysis of broad molecular mass distributions of large molecules. One example is given by the method for determination of MWD of clinical dextran suggested in the Nordic Pharmacopea (Nilsson and Nilsson, 1974). Because Superose 6 has the same type of pore size distributions as Sepharose 6, many analytical applications performed earlier on Sepharose have been transformed to Superose in order to decrease analysis time. However, Sepharose is suitable as a first try out when no information about the composition of the sample, in terms of size, is available. 

Dextrans are particularly useful and are employed as a plasma substitute. A concentration of about 6% dextran (50,000-100,000 relative molecular weight) has equivalent viscosity and colloid-osmotic properties to blood plasma. Dextran can also be used as non-irritant absorbent wound dressings, an application also suited to alginate gels. 

Dextrans are produced commercially for use as plasma substitutes (plasma expanders) which can be administered by intravenous injection to maintain or restore the blood volume. They can be used in applications to ulcers or bum wounds where they form a hydrophilic layer which absorbs fluid exudates. 

Flodin, P. Dextran Gels and Their Applications in Gel Filtration Halmatd, Uppsala, 1962. 

Nishi et al. [110] used dextran and dextrin as chiral selectors in capillary-zone electrophoresis. Polysaccharides such as dextrins, which are mixtures of linear a-(l,4)-linked D-glucose polymers, and dextrans, which are polymers of D-glucose units linked predominantly by a-(l,6) bonds, have been employed as chiral selectors in the capillary electrophoretic separation of enantiomers. Because these polymers are electrically neutral, the method is applicable to ionic compounds. The enantiomers of basic or cationic drugs such as primaquine were successfully separated under acidic conditions. The effects of molecular mass and polysaccharide concentration on enantioselectivity were investigated. 

Dextrans are also attractive as macromolecular carriers of paramagnetic chelates because of their hydrophilicity, the different available molecular weights with narrow polydispersity, and the versatility of activation methods applicable. Several DTPA- or DOTA-loaded carboxymethyl dextran (CMD) derivatives have been prepared and tested in blood pool MRI.136-139 The relaxivities reported for these compounds are, however, relatively moderate. 

F. Paul, E. Oriol, D. Auriol, and P. Monsan, Acceptor reaction of a highly purified dextransucrase with maltose and oligosaccharides. Application to the synthesis of controlled molecular weight dextrans, Carbohydr. Res., 149 (1986) 433-441. 

Even though the short oligosaccharide segment made of seven units may not be considered as a true polymer chain, the chemistry devised by them should be easily applicable to longer saccharidic chains. Liu and Zhang used the Michael reaction for coupling a dextran (Dex) with an amino-functionalized terminal and acrylolyl end-capped PCL [146]. Sun et al. also synthesized Dex-b-PCL by disulfide bond formation [147]. 

The following protocols make use of the compounds adipic acid dihydrazide and carbohy-drazide to derivatize molecules containing aldehydes, carboxylates, and alkylphosphates. The protocols are applicable for the modification of proteins, including enzymes, soluble polymers such as dextrans and poly-amino acids, and insoluble polymers used as micro-carriers or chromatographic supports. 

Several types of enzymatic reactions were studied during the last decade for the biosynthesis of dextran. Reports on the application of chromatographic reactors for an enzyme catalyzed reaction were first demonstrated in the late 1980s [171, 172]. 

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