Dextran sucrose

M. Ressing, W. Jiskoot, H. Talsma, C. van Ingen, E. Beuvery, and D. Crommelin, The influence of sucrose, dextran, and hydroxypropyl-beta-cyclodextrin as lyoprotectants for freeze-dried mouse IgG2a monoclonal antibosy (MN12), Pharm. Res., 9, 266... 

Dextrans are giucose poiymers produced by bacteriai digestion of sucrose. Dextrans with different average moiecuiar weights are avaiiabie. Dextran 70 (6%, 70 kDa) and dextran 40 (10%, 40 kDa) are the most wideiy used soiutions. Because dextran soiutions are poiydisperse, i.e. they consist of moiecuies with a wide range of moiecuiar weights, the initiai voiume expansion is reiativeiy short. 

Bulking agents mannitol, lactose, sucrose, dextran. 

Dextran Sucrose. Dextrans are produced by the bacteria Leuconostoc mesenteroides from sucrose. The reaction is catalyzed by a glucotrans-ferase, which has been purified and which produces little if any free glucose.Similar enzymes appear to be present in other bacteria. The reaction catalyzed by dextran sucrase is ... 

The second section contains six chapters emphasizing saccharides and polysaccharides with natural feed stocks derived from sucrose, dextran, cellulose, cotton, xylan, chitin, starch, and bagasse for potential applications as commercial insulation, topical medical applications, fire retardant articles, durable roofing panels, and other building materials. 

These products exhibited a wide variety of biological activities ranging from very specific, particularly when utilizing synthetic alcohol-containing reactants such as poly(vinyl alcohol), to very broad ranging, particularly when employing natural alcohol-containing reactants such as sucrose, dextran, cellulose, and xylan (see, e.g.. Refs. 39, 40). 

Dextran. This polysaccharide is produced from sucrose by certain species of l euconostoc (70). Dextran [9004-54-0] was the first commercial microbial polysaccharide. It was used as a blood plasma extender in the U.S. Army during the late 1940s and early 1950s. This program was discontinued in 1955. 

The above chemicals can be obtained by fermentation (qv) of other sugars. However, some compounds require sucrose as a unique feedstock. Examples are the polysaccharides dextran, alteman, andlevan, which are produced by specific strains of bacteria (48,54—56). Dextrans are used to make chromatographic separation media, and sulfated dextran derivatives are used as plasma extenders (41). Levans show promise as sweetness potentiators and, along with alteman, have potential as food thickeners and bulking agents in reduced-caloric foods (55,56) (see Carbohydrates). 

Polarimetric determination of the sucrose concentration of a solution is vaUd when sucrose is the only optically active constituent of the sample. In practice, sugar solutions are almost never pure, but contain other optically active substances, most notably the products of sucrose inversion, fmctose and glucose, and sometimes also the microbial polysaccharide dextran, which is dextrorotatory. Corrections can be made for the presence of impurities, such as invert, moisture, and ash. The advantage of polarization is that it is rapid, easy, and very reproducible, having a precision of 0.001°. 

Sucrose is subjected to the action of the bacterium Leuconostoc mesenteroides B 512 and the crude, high-molecular weight dextran thus formed is hydrolyzed and fractionated to an average molecular weight of about 40,000 as measured by light-scattering techniques. 

Homopolysaccharides are synthesised by relatively few spedfic enzymes and are not constructed from subunits. The commerdally important homo polymer dextran is synthesised extracellularly by the enzyme dextransucrase. In Leuconostoc mesenteroides the enzyme is induced by the substrate sucrose. This is deaved to release free fructose and link the glucose to the redudng end of the acceptor dextran chain, which is bound to the enzyme. The product from this bacterium is composed almost exdusively of... 

There are two types of stationary phases commonly used in exclusion chromatography silica gel and micro-reticulated cross-linked polystyrene gels. A third type of exclusion media is comprised of the Dextran gels. Dextran gels are produced by the action of certain bacteria on a sucrose substrate. They consist of framework of glucose units that can form a gel in aqueous solvents that have size exclusion properties. Unfortunately the gels are mechanically weak and thus, cannot tolerate the high pressures necessary for HPLC and, as a consequence, are of very limited use to the analyst. 

A Note on the Dextran Produced from Sucrose by Betacoccus arabinosaceous Haemolyticus, M. Stacey and F. R. Youd, Biochem. J., 32 (1938) 1943-1945. 

Polysaccharides. Part XXIX. Constitution of the Dextran Produced from Sucrose by Leuconostoc dextranicum (Belacoccus arabinosaceous Haemoiyticus), S. Peat, E. Schliichterer, and M. Stacey, /. Chem. Soc., (1939) 581-585. 

Structure of the Dextran Synthesised from Sucrose by a New Strain of Betacoccus arabinosa-ceous" M. Stacey and G. Swift, J. Chem. Soc., (1948) 1555-1559. 

When replacing iron stores in patients receiving ESA therapy, the general approach to treatment is to give a total of 1 g of IV iron, administered in smaller, sequential doses. Because iron stores deplete quickly in patients who do not receive iron supplementation, maintenance doses are often used, particularly in patients receiving hemodialysis. Maintenance doses consist of smaller doses of iron administered weekly or with each dialysis session (e.g., iron dextran or iron sucrose 20 to 100 mg per week sodium ferric gluconate 62.5 to 125 mg per week). 

Parenteral iron therapy currently is available in three different formulations, which are listed in Table 63-3. Iron dex-tran was the first parenteral iron formulation to be approved, followed by ferric gluconate, and then iron sucrose. Although these newer agents are only approved by the Food and Drug Administration (FDA) to treat anemia associated with CKD in patients receiving erythropoietin products, they are effective in treating iron-deficiency anemia as well. Iron dextran is FDA approved for treating documented iron deficiency in patients who are unable to tolerate the oral formulation. 

Iron-deficiency anemia in chronic PN patients may be due to underlying clinical conditions and the lack of iron supplementation in PN. Parenteral iron therapy becomes necessary in iron-deficient patients who cannot absorb or tolerate oral iron. Parenteral iron should be used with caution owing to infusion-related adverse effects. A test dose of 25 mg of iron dextran should be administered first, and the patient should be monitored for adverse effects for at least 60 minutes. Intravenous iron dextran then may be added to lipid-free PN at a daily dose of 100 mg until the total iron dose is given. Iron dextran is not compatible with intravenous lipid emulsions at therapeutic doses and can cause oiling out of the emulsion. Other parenteral iron formulations (e.g., iron sucrose and ferric gluconate) have not been evaluated for compounding in PN and should not be added to PN formulations. 

---