Name: Potassium Citrate
CAS No: 2-Hydroxy-1,2,3-propanetricarboxylic acid tripotassium salt monohydrate [6100-05-6], 2-Hydroxy-1,2,3-propanetricarboxylic acid tripotassium salt anhydrous [866-84-2].
BP: Potassium Citrate PhEur: Potassium Citrate USP: Potassium Citrate
Citrate of potash; citric acid potassium salt; E332; kalii citras; tripotassium citrate
2-Hydroxy-1,2,3-propanetricarboxylic acid tripotassium salt monohydrate [6100-05-6], 2-Hydroxy-1,2,3-propanetricarboxylic acid tripotassium salt anhydrous [866-84-2].
C6H5K3O7H2O 324.41 (for monohydrate) C6H5K3O7 306.40 (for anhydrous
Potassium citrate is used in beverages, foods, and oral pharmaceutical formulations as a buffering and alkalizing agent. It is also used as a sequestering agent and as a therapeutic agent to alkalinize the urine and to relieve the painful irritation caused by cystitis.(1–5) See Table I.
Transparent prismatic crystals or a white, granular powder. Potassium citrate is hygroscopic and odorless, and has a cooling, saline taste.
See Table II.
Acidity/alkalinity pH = 8.5 (saturated aqueous solution). Density 1.98 g/cm3 Melting point 2308C (loses water of crystallization at 1808C). NIR spectra see Figure 1. Solubility see Table III.
Potassium citrate is a stable, though hygroscopic material, and should be stored in an airtight container in a cool, dry place. It is deliquescent in moist air.
Aqueous potassium citrate solutions are slightly alkaline and will react with acidic substances. Potassium citrate may also precipitate alkaloidal salts from their aqueous or alcoholic solutions. Calcium and strontium salts will cause precipitation of the corresponding citrates. Potassium citrate is incompatible with strong oxidizing agents.
Potassium citrate is prepared by adding either potassium bicarbonate or potassium carbonate to a solution of citric acid until effervescence ceases. The resulting solution is then filtered and evaporated to dryness to obtain potassium citrate.
Potassium citrate is used in oral pharmaceutical formulations and is generally regarded as a nontoxic and nonirritant material by this route of administration. Most potassium citrate safety data relate to its use as a therapeutic agent, for which up to 10 g may be administered daily, in divided doses, as a treatment for cystitis. Although there are adverse effects associated with excessive ingestion of potassium salts, the quantities of potassium citrate used as a pharmaceutical excipient are insignificant in comparison to those used therapeutically. LD50 (IV, dog): 0.17 g/kg(6)
Observe normal precautions appropriate to the circumstances and quantity of material handled. Potassium citrate may be irritant to the skin and eyes and should be handled in a well-ventilated environment. Eye protection and gloves are recommended. When heated to decomposition, potassium citrate emits toxic fumes of potassium oxide.(6)
GRAS listed. Accepted as a food additive in Europe. Included in the FDA Inactive Ingredients Database (oral solutions and suspensions; topical emulsions and aerosol foams). Included in nonparenteral medicines (cutaneous foams and emulsions; oral liquids, granules, mixtures and soluble tablets; topical liquids, emulsions and mousses) licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.
Each gram of potassium citrate monohydrate represents approximately 9.3 mmol of potassium and 3.08 mmol of citrate. Potassium citrate monohydrate 2.77 g is equivalent to about 1 g of potassium. Each gram of potassium citrate anhydrous represents approximately 9.8 mmol of potassium and 3.26 mmol of citrate. A specification for potassium citrate is contained in the Food Chemicals Codex (FCC).(7) The EINECS number for potassium citrate is 212-755-5. The PubChem Compound ID (CID) for potassium citrate monohydrate includes 22470 and 2735208.