For sem 3 B.pharm students GTU

1. Prepared by ~ Milan chovatiya
B.Pharm. Sem -3
APIP, Jamnagar
Guide by: Mrs. Pooja Khanpara

2.  Synonyms
 Biological source
 Geographical source
 Preparation
 Description
 Chemical constituents
 Identification test
 Uses

3.  Synonyms Sodium alginate; Alginic acid
sodium; Sodium polymannuronate; Kelgin;
Minus; Protanal;
 Biological Source Algin: is a gelling
polysaccharide extracted from the giant
brown seaweed (giant kelp. Macrocystis
pyrifera L.) Ag., Lessoniaceae) or
from horsetail kelp (Laminaria
digitata L.) Lamour, Laminariaceae) or
from sugar kelp (Laminaria saccharina L.).
 Some other common species are Laminaria
hyperborea and Ascophyllum nodosum

4.  The different varieties of seaweeds are invariably
found in the Pacific and Atlantic Oceans, more
specifically along the coastal lines of USA, Canada,
Scotland, Japan and Australia.
 In India the Western coast of Saurashtra is also a
potential source of algin. However, USA, and UK
are the largest producers of algin in the world.

5.  The algin (or sodium alginate) is the sodium salt of
alginic acid which is a purified carbohydrate
extracted from brown seaweed (algae) by the
careful treatment with dilute sodium hydroxide.
 The brown colour of the crude algin is due to the
presence of a carotenoid pigment
 associated with it which may be eliminated by
treating the aqueous solution with activated carbon
and spray drying the powder.

6.  Colour : Yellowish-white, cream coloured, buff
coloured
 Odour : Odourless
 Taste : Tasteless
 Solubility : Insoluble in alcohol, ether, chloroform
and strong acids, freely soluble in water
 Viscosity : A 1% (w/v) aqueous solution at 20°C
may show a viscosity ranging between 20-
400 centipoises.

7.  Alginic acid is mainly comprised of D-mannuronic
acid residues which on methylation and hydrolysis
gives rise to the formation of 2,3 dimethyl-D-
mannuronide.
 Therefore, the ring as well as bridge oxygen atoms
involve C-4 and C-5 and the carboxyl groups are
absolutely free to react (to form sodium salts),
whereas the aldehydic moieties are duly utilized by
the respective glycosidic linkages.
 It has been observed that these mannuronic acid
entities are joined by β-1, 4-glycosidic linkages. The
resulting structure could be either linear or very
slightly branched.

8.  1. The aqueous solution of algin gives an instant white
copious precipitate with calcium chloride solution.
 2. A 1% (w/v) aqueous solution of algin yields a heavy
gelatinous precipitate with diluted sulphuric acid.
 3. It is not precipitated by saturated ammonium sulphate
solution (distinction from agar and tragacanth)
 4. It gives effervescence (liberates CO2) with
carbonates.
 5. It readily reacts with compounds having ions of alkali
metals (e.g., Na+, K+, Li+) or ammonium (NH4
+) or
magnesium (Mg2+ ) to produce their respective alginates
(salts) that are water soluble and forms thick and
viscous solutions characteristic of hydrophillic colloids.

9.  1. It is extensively used in the manufacture of ice-creams
where it serves as a stabilizing colloid, ensuring creamy
texture thereby checking the growth of ice-flakes (or
crystals).
 2. It is also used in the flocculation of suspended solids in
most water treatment plants.
 3. It is employed as a stabilizing and thickening agent in food
and pharmaceutical industry.
 4. It is used as a film and film-forming agent in the rubber and
paint industry.
 5. It is widely used in the textile industry as absorbable
haemostatic dressings.
 6. It is employed as a binding and distintegrating agent for
tablets and lozenges.