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Recent Progress in Polymer Therapeutics as Nanomedicines
Published in Dan Peer, Handbook of Harnessing Biomaterials in Nanomedicine, 2021
Sahar Israeli Dangoor, Shani Koshrovski Michael, Hemda Baabur-Cohen, Liora Omer, Ronit Satchi-Fainaro
Several polysaccharides are being used as polymeric carriers [14–16]. Among natural and semi-synthetic polysaccharides, hyaluronic acid, chitosan and dextran have been largely investigated for drug bioconjugation [14]. Dextran is a natural polysaccharide containing monomers of simple sugar glucose. This polyglucose biopolymer is characterized by a-1,6 linkages, with hydroxylated cyclohexyl units [15]. Dextran has been particularly popular owing to its clinical approval for use as a plasma expander. Dextran is a water-soluble biopolymer, but it can also dissolve in some organic solvents, such as dimethyl sulfoxide (DMSO), dimethylformamide (DMF), formamide, ethylene glycol, and glycerol. Dextran is biocompatible and biodegradable in blood and in the gastrointestinal (GI) tract [17–20]. However, it is not degraded in lysosomes. Dextran possesses multiple primary and secondary hydroxyl groups that can be used for binding drugs or proteins directly or via spacers [16, 21]. Recently, OsteoDex, a novel bifunctional cytotoxic bone-targeting polybisphosphonate was developed for the treatment of bone metastases in prostate and breast cancer. It consists of a Dextran backbone conjugated to alendronic acid and aminoguanidine, which demonstrated significant bifunctional efficacy of inhibiting bone resorption and anti-tumor effect [19]. A phase I Clinical study was recently completed in patients with castration-resistant prostate cancer (CRPC) [20] and a phase II clinical study is currently ongoing.
Applications of Green Polymeric Nanocomposites
Published in Satya Eswari Jujjavarapu, Krishna Mohan Poluri, Green Polymeric Nanocomposites, 2020
Mukesh Kumar Meher, Krishna Mohan Poluri
Dextran is a water-soluble homopolysaccharide composed of (1→6)-linked α-d-glucopyranose repeating units (Sidebotham 1974). Different varieties of dextran polysaccharides with different ranges of molecular weights and branching are produced by different microorganisms. Commercially available dextran is produced by the nonpathogenic bacteria Leuconostoc mesenteroides (Soetaert et al. 1995). The average molecular weight of dextran ranges from 1 kDa to 40,000 kDa. Dextrans have excellent volume expansion properties and inhibitory effects on thrombocyte aggregation and coagulation factors (Polifka and Habermann 2015, Reuvers 2001). Dextran has been used as an excellent coating polymer to improve biocompatibility (Estevanato et al. 2012). Therefore, dextran is extensively explored in biomedical applications and the pharmaceutical industry (Zahedi et al. 2017, Karandikar et al. 2017).
Enzyme Catalysis
Published in Harvey W. Blanch, Douglas S. Clark, Biochemical Engineering, 1997
Harvey W. Blanch, Douglas S. Clark
Other important microbial polysaccharides include dextran, alginate and pullulan. Dextran is produced by Leuconostoc mesenteroides by the action of dextran sucrase. It can also be produced directly from sucrose by the action of dextran sucrase. Dextran is a branched neutral polysaccharide consisting primarily of 1,6 linkages of glucose monomers. Branching occurs at the 3 position. Dextran is used in molecular sieves for separating molecules on the basis of size. Alginate is primarily obtained from seaweed, but microbial routes are available from Azotobacter vinlandii. Alginates are linear polysaccharides containing mannopyranosyluronic and guluronic acid residues. Pullulan and scleroglucan are also produced by fermentation. Table 8.7. Major food and industrial uses of xanthan gum [From A. Margaritis and G. Pace, Comprehensive Biotechnology, Vol 3, Chapter 49, Pergamon Press (1985)]. Food Applications
Synthesis and characterization of Dextran, poly (vinyl alcohol) blend biopolymer electrolytes with NH4NO3, for electrochemical applications
Published in International Journal of Green Energy, 2022
T. Maheshwari, K. Tamilarasan, S. Selvasekarapandian, R. Chitra, M Muthukrishnan
Among the various biopolymers available, Dextran has a considerable attention because of its nontoxicity, good water solubility, and stability under mild acid and basic conditions, easily filtered, biocompatible, biodegradable nature, and presence of a large number of hydroxyl groups for conjugation. Dextran has been widely used in food industry, manufacturing blood plasma extenders, cosmetics, anticoagulant therapy and so on (Leathers, Hayman, and Cote 1995). It is a complex branched polysaccharide. The parent chain of dextran consists of α-1,6 glycosidic linkages. The branches begin from α-1,4 linkage (α-1,2 and α-1,3 linkages) as well (Lakshmi Bhavani and Nishadextran 2010). Dextran is a microorganism based polysaccharide and it is produced using microorganisms like Leuconostoc, Mesenteroides, Lacobacillus, and so on. Its structure is shown in scheme 1.
Industrial production and applications of α/β linear and branched glucans
Published in Indian Chemical Engineer, 2021
Geetha Venkatachalam, Senthilkumar Arumugam, Mukesh Doble
α-glucans are glucose monomers linked by α-glucosidic bonds. The structure of α-glucans varies on different microbial strain. Dextran (Figure 1A) is produced by Lactobacillus hilgardii, Leuconostoc, mesenteroides, Leuconostoc dextranicum and Streptococcus. Amylopectin (Figure 1B) are highly branched glucans (main component 70–85% in common starches) which are found in higher plants (corn, rice and sorghum) and animals. Glycogen (Figure 1C) are highly branched α-glucans (contains 60,000 glucose residues) which are major carbohydrate forms (liver 6–8% wet weight), and are found in animals and higher plants (starch analog) [5]. Pullulan (Figure 1D), the water-soluble gum-like glucans are produced by strains of Aureobasidium pullulans [4,6,7]. Pea starch (Figure 1E) are highly branched glucans with rich amylose content and are derived from plant sources. An overview of some of the important α glucans, their manufacturers and applications are listed in Table 1 [8–12].
Progress in spray-drying of protein pharmaceuticals: Literature analysis of trends in formulation and process attributes
Published in Drying Technology, 2021
Joana T. Pinto, Eva Faulhammer, Johanna Dieplinger, Michael Dekner, Christian Makert, Marco Nieder, Amrit Paudel
Dextran is composed of α-(1,6)-linked glucan with side chains attached to the C-3 position of the backbone.[151] The side chains vary in length, originating dextran molecules with distinct degree of polymerization (DP) and, hence different physicochemical properties (e.g. molecular weight, solubility, flexibility, etc.). Dextran having various molecular weights, from 1 to 70 kDa, have been applied to the formulation of proteins via spray-drying, with weights between 40 and 70 kDa being preferred. Dextran in combination with mannitol and trehalose have successfully been applied in the stabilization of recombinant viral vaccines[130,131] and bacteriophages formulations.[134] However, dextran with 1 kDa and 60–70 kDa were not so successful, when stabilizing IgG formulations[11] and a tuberculosis vaccine[118] via spray-drying. Used alone, dextran of 20, 40, and 70 kDa have been unsuccessful stabilizing formulations of methionyl human hormone growth[148] and transport proteins.[98] One report describes the successful use of 10 kDa dextran to stabilize an investigational peptide hormone.[152] However, the presence of a larger percentage of reducing groups on smaller molecular weight dextran[150] should be carefully considered when selecting these as excipients.