Definition
ChEBI: A potassium salt that is the monopotassium salt of carbonic acid. It has fungicidal properties and is used in organic farming for the control of powdery mildew and apple scab.
Production Methods
Potassium bicarbonate can be made by passing carbon dioxide into
a concentrated solution of potassium carbonate, or by exposing
moist potassium carbonate to carbon dioxide, preferably under
moderate pressure.
Potassium bicarbonate also occurs naturally in the mineral
calcinite.
General Description
Potassium bicarbonate is water soluble alkaline potassium salt with monoclinic crystalline structure. It is a raw material for the synthesis of many potassium compounds. It is a better coolant than sodium bicarbonate in the aerosol fire extinguishing apparatus. It shows potential as an antifungal agent.
Flammability and Explosibility
Nonflammable
Agricultural Uses
Potassium bicarbonate (KHCO3), also called potassium
hydrogen carbonate, is a white crystalline solid, soluble
in water (insoluble in ethanol). It decomposes at about
120°C. Potassium bicarbonate contains about 28%
potassium (K2O) and used as a potassium supplying
fertilizer.
Potassium bicarbonate, which occurs naturally as
calcinite, is made by passing carbon dioxide into
saturated potassium carbonate solution. It is used as
baking powder and as a fire extinguisher.
Pharmaceutical Applications
Alkali metal carbonates and bicarbonates have wide-ranging pharmaceutical applications. Potassium bicarbonate or citrate is used in over-the-counter drugs as active pharmaceutical ingredients (APIs) against urinary-tract infections (increasing the pH of the urine) in the United Kingdom.
Oralbicarbonate solutions such as potassium bicarbonate are typically given orally for chronic acidosis states low pH of the blood plasma. This can be again due to impaired kidney function. The use of potassium bicarbonate for the treatment of acidosis has to be carefully evaluated, as even small changes of the potassium plasma levels can have severe consequences.
Pharmaceutical Applications
As an excipient, potassium bicarbonate is generally used in
formulations as a source of carbon dioxide in effervescent
preparations, at concentrations of 25–50% w/w. It is of particular
use in formulations where sodium bicarbonate is unsuitable, for
example, when the presence of sodium ions in a formulation needs
to be limited or is undesirable. Potassium bicarbonate is often
formulated with citric acid or tartaric acid in effervescent tablets or
granules; on contact with water, carbon dioxide is released through
chemical reaction, and the product disintegrates. On occasion, the
presence of potassium bicarbonate alone may be sufficient in tablet formulations, as reaction with gastric acid can be sufficient to cause
effervescence and product disintegration.
Potassium bicarbonate has also been investigated as a gasforming
agent in alginate raft systems.The effects of potassium
bicarbonate on the stability and dissolution of paracetamol and
ibuprofen have been described.
Potassium bicarbonate is also used in food applications as an
alkali and a leavening agent, and is a component of baking powder.
Therapeutically, potassium bicarbonate is used as an alternative
to sodium bicarbonate in the treatment of certain types of metabolic
acidosis. It is also used as an antacid to neutralize acid secretions in
the gastrointestinal tract and as a potassium supplement.
Safety
Potassium bicarbonate is used in cosmetics, foods, and oral
pharmaceutical formulations, where it is generally regarded as a
relatively nontoxic and nonirritant material when used as an
excipient. However, excessive consumption of potassium bicarbonate
or other potassium salts may produce toxic manifestations of
hyperkalemia.
storage
Potassium bicarbonate should be stored in a well-closed container
in a cool, dry location. Potassium bicarbonate is stable in air at
normal temperatures, but when heated to 100–200°C in the dry
state, or in solution, it is gradually converted to potassium
carbonate.
Purification Methods
It is crystallised from water at 65-70o (1.25mL/g) by filtering and then cooling to 15o (~0.4ml/g). During all operations, CO2 is passed through the stirred mixture. The crystals are sucked dry at the pump, washed with distilled water, dried in air and then over H2SO4 in an atmosphere of CO2. It is much less soluble than the carbonate in H2O (see below).
Incompatibilities
Potassium bicarbonate reacts with acids and acidic salts with the
evolution of carbon dioxide.
Regulatory Status
E501 refers to potassium carbonates). Included in nonparenteral
medicines licensed in the UK and USA (chewable tablets;
effervescent granules; effervescent tablets; lozenges; oral granules;
oral suspensions; powder for oral solutions). Included in the
Canadian List of Acceptable Non-medicinal Ingredients.
