Citric Acid Monohydrate

Nonproprietary Names
BP: Citric Acid Monohydrate
JP: Citric Acid Hydrate
PhEur: Citric Acid Monohydrate
USP: Citric Acid Monohydrate 

Synonyms
Acidum citricum monohydricum; E330; 2-hydroxypropane-1,2,3-tricarboxylic acid monohydrate.

Description
Citric acid monohydrate occurs as colorless or translucent crystals, or as a white crystalline, efflorescent powder. It is odorless and has a strong acidic taste. The crystal structure is orthorhombic.

Chemical Name: 2-Hydroxy-1,2,3-propanetricarboxylic acid monohydrate

CAS Registry Number: [5949-29-1]

Empirical Formula: C6H8O7H2O

Molecular Weight: 210.14 

Acidifying agent; antioxidant; buffering agent; chelating agent; flavor enhancer; preservative.

• Citric acid (as either the monohydrate or anhydrous material) is widely used in pharmaceutical formulations and food products, primarily to adjust the pH of solutions.
• It has also been used experimentally to adjust the pH of tablet matrices in enteric-coated formulations for colon-specific drug delivery. 
• Citric acid mono hydrate is used in the preparation of effervescent granules, while anhydrous citric acid is widely used in the preparation of effervescent tablets. 
• Citric acid has also been shown to improve the stability of spray-dried insulin powder in inhalation formulations. 
• In food products, citric acid is used as a flavor enhancer for its tart, acidic taste. 
• Citric acid monohydrate is used as a sequestering agent and antioxidant synergist. 
• It is also a component of anticoagulant citrate solutions. 
• Therapeutically, preparations containing citric acid have been used to dissolve renal calculi.

Citric acid is incompatible with potassium tartrate, alkali and alkaline earth carbonates and bicarbonates, acetates, and sulfides. Incompatibilities also include oxidizing agents, bases, reducing agents, and nitrates. It is potentially explosive in combination with metal nitrates. On storage, sucrose may crystallize from syrups in the presence of citric acid

Citric acid is found naturally in the body, mainly in the bones, and is commonly consumed as part of a normal diet. Orally ingested citric acid is absorbed and is generally regarded as a nontoxic material when used as an excipient. However, excessive or frequent consumption of citric acid has been associated with erosion of the teeth.

Citric acid and citrates also enhance intestinal aluminum absorption in renal patients, which may lead to increased, harmful serum aluminum levels. It has therefore been suggested that patients with renal failure taking aluminum compounds to control phosphate absorption should not be prescribed citric acid or citrate-containing products.

Observe normal precautions appropriate to the circumstances and quantity of material handled. Eye protection and gloves are recommended. Direct contact with eyes can cause serious damage. Citric acid should be handled in a well-ventilated environment or a dust mask should be worn. It is combustible.

Anhydrous citric acid; fumaric acid; malic acid; sodium citrate dihydrate; tartaric acid.