International Numbering System (INS) for Food Additives: 524
Food additives Europe numbers: E524
Functional Category
Alkalizing agent; buffering agent.
Applications in Pharmaceutical Formulation
Sodium hydroxide is widely used in pharmaceutical formulations to adjust the pH of solutions.(1) It can also be used to react with weak acids to form salts
Description
Sodium hydroxide occurs as a white or nearly white fused mass. It is available in small pellets, flakes, sticks, and other shapes or forms. It is hard and brittle and shows a crystalline fracture. Sodium hydroxide is very deliquescent and on exposure to air it rapidly absorbs carbon dioxide and water.
Stability and Storage Conditions
Sodium hydroxide should be stored in an airtight nonmetallic container in a cool, dry place. When exposed to air, sodium hydroxide rapidly absorbs moisture and liquefies, but subsequently becomes solid again owing to absorption of carbon dioxide and formation of sodium carbonate.
Incompatibilities
Sodium hydroxide is a strong base and is incompatible with any compound that readily undergoes hydrolysis or oxidation. It will react with acids, esters, and ethers, especially in aqueous solution.
Safety
Sodium hydroxide is widely used in the pharmaceutical and food industries and is generally regarded as a nontoxic material at low concentrations. At high concentrations it is a corrosive irritant to the skin, eyes, and mucous membranes. LD50 (mouse, IP): 0.04 g/kg(2) LD50 (rabbit, oral): 0.5 g/kg