Aluminum hydroxide is a white, amorphous powder or gel, odorless and tasteless. It is practically insoluble in water but dissolves in acidic and basic solutions. It neutralizes stomach acid by forming aluminum salts and water.
Chemical Name and CAS Registry Number:Aluminum hydroxide [21645-51-2]
Functional Category:Antacid; adsorbent; emulsifying agent
Identification: Positive for aluminum and hydroxide
Assay (Al(OH)₃ content): 76.5%–83.5%
Loss on Ignition: ≤35%
Acid-Neutralizing Capacity: ≥ 20 mEq/g
pH (1% suspension): 6.0–8.0
Microbial Limits: Complies with pharmacopeial standards
Antacid: Used in suspensions and tablets to relieve symptoms of hyperacidity, indigestion, and peptic ulcer disease.
Adsorbent: Binds toxins and gases in the GI tract.
Emulsifying Agent: Occasionally used in vaccines as an adjuvant to enhance immune response.
Aluminum hydroxide is a commonly used antacid with a slower onset and longer duration than magnesium-based antacids. It can cause constipation and is often combined with magnesium hydroxide to balance GI effects. It also plays a role in vaccine formulations due to its immunostimulatory properties.
