Aluminum hydroxide n Dried aluminum hydroxide

Aluminium hydroxide or Aluminum hydroxide is used to formulate antacid. Aluminium hydroxide, Al(OH)3, archaically called hydrate of alumina or alumina trihydrate (Al2O3·3H2O), is found in nature as the mineral gibbsite. This chemical acts as a suitable catalyst carrier. It does not dissolve in water. Aluminum hydroxide is used to treat symptoms of increased stomach acid, such as heartburn, upset stomach, sour stomach, or acid indigestion. This is used as an antacid in humans and animals. It is also used to reduce phosphate levels in people with certain kidney conditions. Aluminum Hydroxide serves as a suitable filler material for artificial marble items and as flame proof material used for processing rubber and plastic. Aluminum Hydroxide and Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They may be used to treat these symptoms in patients with peptic ulcer, gastritis, esophagitis, hiatal hernia, or too much acid in the stomach. They combine with stomach acid and neutralize it.

General Specifications of Aluminium hydroxide or Aluminum hydroxide:
Appearance: White crystal or powder.
Assay as Al(OH)3: 99.4% minimum.
SiO2: 0.02% maximum.
Na2O: 0.3% maximum.
Fe2O3: 0.02% maximum.
Loss on ignition: 34.5 ± 0.5%
pH: 8.0 - 10.0
Electrical conductivity: 150 us/cm maximum.
Moisture: 0.3% maximum.
Whiteness: 96% minimum.
D50: 1.3 - 2.1 μm
Oil absorption (linseed oil): 50 mL/100g maximum.
Na2O (soluble): 0.03% maximum.
Specific surface area: 3 - 6 m2/g
Relative density: 2.4
Sieve analysis (% on 325 mesh): 0.1% maximum.

Aluminum Hydroxide Gel USP Grade:
Al(OH)3 --- 78.00 --- [21645-51-2].

Aluminum Hydroxide Gel is a suspension of amorphous aluminum hydroxide in which there is a partial substitution of carbonate for hydroxide. It contains the equivalent of not less than 90.0 percent and not more than 110.0 percent of the labeled amount of aluminum hydroxide [Al(OH)3]. It may contain Peppermint Oil, Glycerin, Sorbitol, Sucrose, Saccharin, or other suitable flavors, and it may contain suitable antimicrobial agents.

Packaging and storage: Preserve in tight containers, and avoid freezing.
Identification:
A: Place about 1 g in a flask equipped with a stopper and glass tubing, the tip of which is immersed in calcium hydroxide in a test tube. Add 5 mL of 3 N hydrochloric acid to the flask, and immediately insert the stopper: gas evolves in the flask and a precipitate is formed in the test tube.
B: The solution remaining in the flask responds to the tests for Aluminum.
Microbial limits: Its total aerobic microbial count does not exceed 100 cfu per mL, and it meets the requirements of the test for the absence of Escherichia coli.
Acid-neutralizing capacity: Not less than 65.0% of the expected mEq value, calculated from the results of the Assay, is obtained. Each mg of Al(OH)3 has an expected acid-neutralizing capacity value of 0.0385 mEq.
pH: between 5.5 and 8.0, determined potentiometrically.
Chloride: Transfer an accurately measured quantity of the Gel, equivalent to 0.6 g of Al(OH)3, to a porcelain dish. Add 0.1 mL of potassium chromate and 25 mL of water. Stir, and add 0.10 N silver nitrate until a faint, persistent pink color is obtained: not more than 8.0 mL of 0.10 N silver nitrate is required [4.7%, based on the Al(OH)3 content].
Sulfate: Add 5.0 mL of 3 N hydrochloric acid to an accurately measured quantity of the Gel, equivalent to 0.3 g of Al(OH)3, and heat to dissolve the specimen under test. Cool, dilute with water to 250 mL, and filter if necessary: a 20-mL portion of the filtrate shows no more sulfate than corresponds to 0.20 mL of 0.020 N sulfuric acid [0.8%, based on the Al(OH)3 content].
Arsenic: --- The limit is 0.001%, based on the Al(OH)3 content.
Heavy metals: Dissolve an accurately measured quantity of the Gel, equivalent to 0.24 g of Al(OH)3, in 10 mL of 3 N hydrochloric acid with the aid of heat, filter, if necessary, and dilute with water to 25 mL: the limit is 0.0083%, based on the Al(OH)3 content.

Dried Aluminium Hydroxide BP Ph Eur Grade:
Hydrated Aluminium Oxide, Ph. Eur.
Action and use: Antacid.

DEFINITION
Content: 47.0 per cent to 60.0 per cent of Al2O3.

CHARACTERS
Appearance: White or almost white, amorphous powder.
Solubility: Practically insoluble in water. It dissolves in dilute mineral acids and in solutions of alkali hydroxides.

IDENTIFICATION
Solution S (see Tests) gives the reaction of aluminium.

TESTS
Solution S: Dissolve 2.5 g in 15 mL of hydrochloric acid, heating on a water-bath. Dilute to 100 mL with distilled water.
Appearance of solution: Solution S is not more opalescent than reference suspension and not more intensely coloured than reference solution.
Alkaline impurities: Shake 1.0 g with 20 mL of carbon dioxide-free water for 1 min and filter. To 10 mL of the filtrate add 0.1 mL of phenolphthalein solution. Any pink colour disappears on the addition of 0.3 mL of 0.1 M hydrochloric acid.
Neutralising capacity: Carry out the test at 37C. Disperse 0.5 g in 100 mL of water, heat, add 100.0 mL of 0.1 M hydrochloric acid, previously heated, and stir continuously; the pH of the solution after 10 min, 15 min and 20 min is not less than 1.8, 2.3 and 3.0 respectively and is at no time greater than 4.5. Add 10.0 mL of0.5 M hydrochloric acid, previously heated, stir continuously for 1 h and titrate with 0.1 M sodium hydroxide to pH 3.5; not more than 35.0 mL of 0.1 M sodium hydroxide is required.
Chlorides: Maximum 1 per cent.
Sulfates: Maximum 1 per cent.
Arsenic: Maximum 4 ppm, determined on 10 mL of solution S.
Microbial contamination:
TAMC: acceptance criterion 103 CFU/g.
TYMC: acceptance criterion 102 CFU/g.
Absence of bile-tolerant gram-negative bacteria.
Absence of Escherichia coli.

ASSAY
Dissolve 0.800 g in 10 ;mL of hydrochloric acid, heating on a water-bath. Cool and dilute to 50.0 mL with water. To 10.0 mL of the solution add dilute ammonia until a precipitate begins to appear. Add the smallest quantity of dilute hydrochloric acid needed to dissolve the precipitate and dilute to 20 mL with water. Carry out the complexometric titration of aluminium.
1 mL of 0.1 M sodium edetate is equivalent to 5.098 mg of Al2O3.

STORAGE
In an airtight container, at a temperature not exceeding 30C.

For Original Monographs of IP Indian Pharmacopoeia BP British Pharmacopoeia USP US Pharmacopoeia FCC Food Grade product, please check with the respective web-pages or books.