Sodium bicarbonate

• BPSodium Bicarbonate
• JPSodium Bicarbonate
• Ph. Eur.Sodium Hydrogen Carbonate
• USP–NFSodium Bicarbonate

Baking soda; bicarbonate of soda; carbonic acid monosodium salt; natrii hydrogenocarbonas; sodium acid carbonate; sodium hydrogen carbonate; E500(ii)

Carbonic acid monosodium salt · [144-55-8]

UNII 8MDF5V39QO · PubChem CID 516892

NaHCO3 · 84.01

pH adjuster, buffering agent

Typical concentrations: — · Dosage forms: Solid, Sterile (parenteral/ophthalmic)

Sodium bicarbonate is used as the carbon dioxide source in effervescent tablets and granules, usually combined with citric and/or tartaric acid, at about 25–50% w/w. It is also used as an alkalising agent and buffer in oral and parenteral formulations, in isotonic infusions (1.39% w/v is iso-osmotic), as a gas-generating agent in floating and raft-forming systems, and therapeutically as an antacid and systemic alkaliniser.

An odourless, white, crystalline powder with a saline, slightly alkaline taste. Grades of different particle size, and surface-treated or granular grades for direct compression, are available.

pH

about 8.3 (freshly prepared 0.1 M aqueous solution)

Thermal decomposition

begins to lose carbon dioxide and water at about 50 °C; converted to sodium carbonate at higher temperatures

Solubility

soluble in water (about 1 in 11 at 20 °C); practically insoluble in ethanol

True density

about 2.2 g/cm³

Stable in dry air but slowly decomposes in moist air. In aqueous solution it gradually loses carbon dioxide and becomes more alkaline, particularly on warming or shaking; autoclaving converts it partly to carbonate, so solutions for injection are usually filter-sterilised or sealed to retain CO2. Store in a well-closed container in a cool, dry place.

Reacts with acids, acidic salts and many acidic drugs with evolution of carbon dioxide. Incompatible with calcium salts in solution (precipitation of calcium carbonate) and with many alkaloidal salts, and may raise pH enough to precipitate drugs that are poorly soluble in alkaline conditions.

Manufactured mainly by the ammonia–soda (Solvay) process or by passing carbon dioxide into a solution of sodium carbonate, which precipitates the less soluble bicarbonate. It may also be obtained from the mineral trona.

Used widely in oral and parenteral products and generally regarded as non-toxic at the levels used as an excipient. Large oral or parenteral doses can cause metabolic alkalosis, sodium overload and fluid retention; oral use releases carbon dioxide, which may cause belching and distension.

Observe normal precautions for the quantity handled. Eye protection and gloves are recommended.

GRAS listed. Accepted as a food additive in Europe (E500). Included in the FDA Inactive Ingredient Database (injections, ophthalmic preparations, oral capsules, solutions and tablets) and in parenteral and non-parenteral medicines licensed in Europe.

Potassium bicarbonate; sodium carbonate; citric acid monohydrate; tartaric acid.

Effervescent products must be made in low-humidity conditions (often below about 25% RH) because traces of moisture start the acid–bicarbonate reaction, which then propagates; dried or coated bicarbonate grades and moisture-protective packaging help stability. Avoid drying temperatures that cause thermal decomposition.