Alginic acids

Alginic acid is mostly used as cell transplantation vehicles to grow new tissues as well as in wound dressing. The main drawbacks of this p olymer material are slow degradation and insufficient mechanical integrity, which makes it impxjssible for long-term implants [15]. 

BP Alginic acid PhEur Acidum alginicum USPNF Alginic acid 

E400 Kelacid-, L-gulo-D-mannoglycuronan polymannuronic acid Protacid Satialgine H8. 

Alginic acid is a linear glycuronan polymer consisting of a mixture of P-(l— 4)-D-mannosyluronic acid and a-(1 4)-L-gulosyluronic acid residues, of general formula (CeHgOlK. The molecular weight is typically 20 000-240 000. 

The PhEur 2005 describes alginic acid as a mixture of polyuronic acids [(CgHgOeU composed of residues of D-mannuronic and L-glucuronic acid, and is obtained mainly from algae belonging to the Phaeophyceae. A small proportion of the carboxyl groups may be neutralized. 

Stabilizing agent suspending agent sustained release adjuvant tablet binder tablet disintegrant viscosity-increasing agent. 

There are also other biomedical applications of alginate acid. Alginate-based microcapsules for immunoisolation of pancreatic islets have been intensively investigated. Also, research concerned with polyionic hydrocolloids for the intestinal delivery of protein drugs by alginate-based material has received much attention.  

Pectin is a linear macro molecule constituent of a(1 4)-linked D-galacturonic acid, and it is a monomer unit partially displaced by ce(1 2)-linked L-rhamnose leading to a new structure called rhamnogalacturnonam I. The other kind of pectin structure is rhamnogalacturonam II, which is less frequent and complex and is a more branched polysaccharide. About 80% of the galacturonic acid carboxyl groups are esterified in methanol. This ratio depends on the extraction conditions and since the proportion of esterified, non-esterified galacturonic acid controls the performance of pectin in food applications. 

These non-esterified galacturonic acid entities may be free acid or salts, with sodium, potassium, or calcium as the counter ion. The partly esterified pectin salts are further named pectinates, and the degree of esterification below 5%, was coined as pectates. 

The polyglycerols both individually or after epoxizing with epichloroyrin are commercially available gelatin resin which was casted on the Teflon trays to make it as film and can be used as an artificial skin. This polymer can be adhered to open wounds and protect against fluid loss and infections. Further when this polymer was loaded with bioactive materials or molecules, these bioactive components can be released for several days until the wound cures. These films are prepared and sterilized with y-rays. 

Examination, by n.m.r. spectroscopy, of the products formed by incubation of D-mannuronan C-5-epimerase with alginic acid containing 13% of L-guluronate indicated that reaction adjacent to an existing L-gulosyluronic residue was favored. The L-guluronate content increased171 to 59%. 

Laminarin.—In a study of the conformations of polysaccharide chains in solution, values for the characteristic ratio (C ) and the steric factor (a) have been computed for laminarin [a jS-(l 3)-linked D-glucan] and an a-(l - 3)-linked D-glucan. Laminarin exhibits lower values for C and a than does the a-(l 3)-linked D-glucan this differs from the situation encountered with a- and /8-(l - 4)-linked D-glucans, suggesting that the chain dimensions of polysaccharides depend, among other factors, on the type and orientation of the inter-unit glycosidic bonds. 

It can be further purified by precipitation with calcium salts. During extraction and purification, some degradation of the polymer takes place and the preparations show varying degrees of polymerization ranging from 1000 to 10000. 

Alginic acid is a linear polymer composed of (i-1,4-D-mannuronic and L-gulucuronic acid the proportions of the two units are not constant in the alginates from different algae species (Fig. 11). 

Sodium alginate is a nearly odorless and tasteless powder which is readily soluble in water, forming a viscous colloidal solution. Free alginic acid is insoluble in cold 

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Algin occurs in all members of the class Phaeophjceae, brown seaweed, as a stmctural component of the cell walls in the form of the insoluble mixed calcium, magnesium, sodium, and potassium salt of alginic acid. 

The viscosity of algiaate solutioas is iadepeadeat of pH ia the range 5—10, but below pH 4.5, the viscosity iacreases uatil the pH reaches 3 whea iasoluble alginic acid precipitates. Propyleae glycol algiaate is soluble and stable at pH 2—3 but not above 6.5. 

The alginic acid content of some of the commercially important brown algae is shown in Table 4. The commercial processes for the production of algin are proprietary (22,23). 

The term alginate refers to the salt forms of alginic acid [9005-32-7] a copolymer of D-mannopyranosyluronic acid [56687-62-8] (1) and L-gulopyranosyluronic acid [56688-68-7] (2) residues. 

Alginic acid is a copolymer of P-D-mannopyranosyluronic acid (1) and a-L-gulopyranosyluronic acid (2) units linked 1— 4, with no detectable... 

Alginic acid [9005-32-7] M 48,000-186000. To 5g in 550mL water containing 2.8g KHCO3, were added 0.3mL acetic acid and 5g potassium acetate. EtOH to make the soln 25% (v/v) in EtOH was added and any insoluble material was discarded. Further addition of EtOH, to 37% (v/v), ppted alginic acid. [Pal and Schubert J Am Chem Soc 84 4384 1962.]... 

Antacid/alginic acid (Gaviscon) 2 tablets or 1 5 mL after meals and at bedtime AND/OR C. Patient-directed therapy Over-the-counter H2RAs (each taken up to twice daily) - Cimetidine 200 mg - Lamotidine 1 0 mg - Nizatidine 75 mg - Ranitidine 75 mg OR Over-the-counter PPI (taken once daily) - Omeprazole 20 mg agent. 

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