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.
- BP: Citric Acid Monohydrate
- JP: Citric Acid Hydrate
- PhEur: Citric Acid Monohydrate
- USP: Citric Acid Monohydrate
Acidum citricum monohydricum; E330; 2-hydroxypropane-1,2,3- tricarboxylic acid monohydrate.
Chemical Name and CAS Registry Number
2-Hydroxy-1,2,3-propanetricarboxylic acid monohydrate [5949-29-1]
Empirical Formula and Molecular Weight: C6H8O7.H2O 210.14
Acidifying agent; antioxidant; buffering agent; chelating agent; flavor enhancer; preservative.
Applications in Pharmaceutical Formulation or Technology
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 monohydrate 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.