Dextran

Absorption

Dextran presents a very low oral bioavailability that is reduced as the chain gets longer. Thus, the bioavailability of dextran is inversely proportional to the length of the carbohydrate chain.

Toxicity

Some reports have shown adverse effects when used in therapeutical doses and some teratogenic effects have been demonstrated when used in large doses. The current LD50 reported in rats is 10700 mg/kg.

Description

Dextrans are glucose polymers produced by bacteria linked in an α-1,6 chain and having an α-1,3 or α-1,4 branch about every fifth residue. The specific positioning of the branching varies by the bacterium producing it. The molecular weights of these chains generally are 40 or 70 kDa (dextran-40 and dextran-70, respectively), and the compounds work via an osmotic gradient similar to the colloids and hypertonic crystalloid solutions.
Dextrans have a longer intravascular residence time than albumin, which limits interstitial edema. As with the crystalloids and other colloids, the dextrans have no oxygen-carrying capacity. Furthermore, because they are bacterial products, the dextrans have the potential to be potent antigens and induce anaphylaxis.

Chemical properties

white crystals or powder

Originator

LMD 10%,Abbott,US,1967

The Uses of Dextran

dextran is a polysaccharide with water-binding properties. It is also used to control product viscosity. Some studies indicate a capacity to enhance the anti-aging activity of formulations containing weak acids, as well as to reduce possible skin irritation arising from such acids.

The Uses of Dextran

Dextran is a polysaccharide composed of glucose molecules used as an antithrombotic to reduce blood viscosity and as a volume expander in anemia. Studies show that it inhibits the mannose receptor-med iated clearance of tissue-type plasminogen activator (t-PA).

The Uses of Dextran

also available in pharma grade

The Uses of Dextran

exhibit borad spectrum of biological activities, with very low anticoagulant capacity: they activate lipoprotein elimination by lipase stimulation, inhibit cell proliferation in vascular wall, regulate transport of plasmatic proteins and inhibit depositi

The Uses of Dextran

antiinflammatory veterinary drug

Indications

Dextran is used as the restoration of blood mass during surgical interventions if there is hypovolemia due to trauma or dehydration. It is as well used after the presence of hemorrhage in cases of blood loss to a level inferior to 15% of the blood mass, if compatibility test cannot be completed or when blood lots need to be tested for pathogen detection. Dextran is also used for the prevention of profound postoperative venous thrombosis.
Dextran as well presents ophthalmic applications as solutions or ointments for the temporary relief of xerophthalmia or minor ocular irritations.

Background

Dextran is a polysaccharide that differs from others in that its glucose units are joined together 1:6 glucoside links. The main chain of glucose has short branches at frequent intervals which are probably joined by 1:3 and 1:4 glucoside links. The chains can be composed of about 200,000 glucose units. Many bacteria, like Leuconostoc, can synthesize dextran from sucrose, and this activity is used commercially to obtain dextran.
Dextran 40 is a sterile, nonpyrogenic preparation of low molecular weight dextran (average mol. wt. 40,000) in 5% Dextrose Injection or 0.9% Sodium Chloride Injection. It is administered by intravenous infusion.
Dextran 75 is a complex branched glucan with an average molecular weight 75000 Daltons. It is produced from certain bacteria that with α-1,6 glycosidic linkages between glucose molecules and α-1,3 linkages between branches. When labelled with technetium Tc99m, dextran 75 is intravenously administered as an imaging agent to detect and diagnose conditions in the vascular compartment such as pericardial effusion or ventricular aneurysm.

What are the applications of Application

Dextran is a multi-use, branched glucan

Definition

dextran: A glutinous glucose polymerproduced by certain bacteria. Itcan be made by fermenting sucrose(cane sugar) and is used as a thickeningagent, as a stabilizer in ice cream,and as a substitute for plasma inblood transfusions. Esters with sulphuricacid yield sodium salts thatare employed as anticoagulant drugs.

Manufacturing Process

Sucrose is subjected to the action of the bacterium Leuconosfoc 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.

brand name

Gentran 40 (Baxter Healthcare).

Therapeutic Function

Plasma extender

General Description

Dextrans are polysaccharides with molecular weights ≥1,000 Dalton, with a linear backbone of α-linked D-glucopyranosyl repeating units. Dextrans are found as bacterial extracellular polysaccharides. They are synthesized from sucrose by Leuconostoc mesenteroides and Lactobacillus brevis. Bacteria employ dextran in biofilm formation or as a protective coating to evade host phagocytes in the case of pathogenic bacteria.
Dextran from Leuconostoc mesenteroides (Mw: 12,000) may be used as an analytical standard to calibrate the column for gel permeation chromatography (GPC).

Biochem/physiol Actions

Dextran is a branched glucan composed of linear a(1→6) linked glucose units and a (1→3) link initiated branches. Dextran ranges in size from 10,000 to 150,000 Kd. Dextrans are used in many applications as volume extenders, stabilizers, matrix components, binding platforms, lubricants and physical structure components.

Mechanism of action

Pharmacokinetics

It is reported that dextran presents an effect on the hemostatic system in particular by prolonging bleeding time. In the same trials, dextran is reported to reduce emboli, reduce platelet adhesiveness and produce hemodilution. These effects have been showed to be greater proportionally with the increase in the molecular weight of the dextran.

Safety Profile

Suspected carcinogen with experimental carcinogenic data. When heated to decomposition it emits acrid smoke and fumes. See also other DEXTRANS.

Veterinary Drugs and Treatments

Dextran 70 is a relatively low cost colloid for the adjunctive treatment of hypovolemic shock. Hetastarch is the more commonly employed synthetic colloid used today.

Metabolism

Long chains of dextran such as dextran 60 are highly metabolized in the liver until formation of lower molecular weight products before being excreted from the body.

Purification Methods

Solutions of dextran keep indefinitely at room temperature if 0.2mL of Roccal (10% alkyldimethylbenzylammonium chloride) or 2mg phenyl mercuric acetate are added per 100mL solution. This inhibits mould growth. [Scott & Melvin Anal Biochem 25 1656 1953.]