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Production Methods

Sodium carbonate is produced by the ammonia-soda process, also known as the Solvay process.

Pharmaceutical Applications

Sodium carbonate is used as an alkalizing agent in injectable, ophthalmic, oral, and rectal formulations. In effervescent tablets or granules, sodium carbonate is used in combination with an acid, typically citric acid or tartaric acid. When the tablets or granules come into contact with water, an acid– base reaction occurs in which carbon dioxide gas is produced and the product disintegrates. Raw materials with low moisture contents are required to prevent the early triggering of the effervescent reaction. As an alkalizing agent, concentrations of sodium carbonate between 2% and 5% w/w are used in compressed tablet formulations. As an effervescent agent, concentrations of sodium carbonate up to 10% w/w can be used. Therapeutically, sodium carbonate is also used as an oral antacid.

Safety

Sodium carbonate is used in injectable, oral, and rectal pharmaceutical formulations. The pure form of sodium carbonate is mildly toxic by ingestion, moderately toxic by inhalation and SC routes, and very toxic by the IP route. It is irritating to the skin and eyes. Dust and vapors of sodium carbonate may irritate mucous membranes, causing coughing and shortness of breath. It also has experimental reproductive effects. Sodium carbonate can migrate to food from packaging materials. When used as an excipient or antacid, sodium carbonate is generally regarded as a nontoxic and nonirritating material. LD50 (mouse, IP): 0.12 g/kg LD50 (mouse, SC): 2.21 g/kg LD50 (rat, oral): 4.09 g/kg

storage

Sodium carbonate converts to the monohydrate form when in contact with water and produces heat. It begins to lose carbon dioxide at temperatures above 400℃ and decomposes before boiling. Store in airtight containers.

Incompatibilities

Sodium carbonate decomposes when in contact with acids in the presence of water to produce carbon dioxide and effervescence. It may react violently with aluminum, phosphorous pentoxide, sulfuric acid, fluorine, and lithium.

Regulatory Status

GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (injections; ophthalmic solution; oral capsules and tablets; rectal suspensions). Included in the Canadian List of Acceptable Non-medicinal Ingredients. Included in parenteral (powder for solution for injection) and nonparenteral medicines (oral effervescent tablets, soluble tablets, granules, lozenges, chewing gums) licensed in the UK. USP32–NF27 allows either the anhydrous or the monohydrate form.

Chemical Composition and Structure

Sodium carbonate monohydrate consists of sodium ions (Na+), carbonate ions (CO3^2-), and water molecules.

Analysis Method

The kinetics and dynamics of sodium carbonate monohydrate reactions can be analyzed using techniques such as thermogravimetric methods, terahertz spectroscopy, and solid-state analytical techniques like scanning electron microscopy and X-ray powder diffraction.^[3]

Industrial uses

The most prominent characteristic of soda ash in solution is the high buffered pH response. For example, changing the sodium carbonate dosage from 0.03% to 30% only causes the solution pH to change from 10.5 to 11.7. Because of this, in mineral processing application, soda ash is used for pH control to a maximum value of 10.5.