Chemical Properties
white powder(s); absorbs atmospheric moisture [MER06]
Uses
Astringent (topical).
Definition
ChEBI: A metal sulfate composed of potassium, aluminium and sulfate ions in the ration 1:1:2.
Production Methods
Potassium alum is manufactured by treating bauxite with sulfuric
acid and then potassium sulfate. Alternatively, aluminum sulfate is
reacted with potassium sulfate.
Flammability and Explosibility
Nonflammable
Pharmaceutical Applications
Potassium alum precipitates proteins and is a powerful astringent.
The ability to precipitate proteins is utilized in the manufacture of
vaccines, where purified proteins are coprecipitated with and
adsorbed onto potassium alum.
Potassium alum is often included in preparations used as
mouthwashes or gargles and in dermatological preparations, and
it may be used as a topical hemostatic, either as a solid or as a
solution. Intravesical instillation of potassium alum, typically as a
1% solution, has been used for hemorrhagic cystitis.
Safety
Potassium alum is often included in preparations used as
mouthwashes or gargles and in dermatological preparations.
Large doses of potassium alum act as an irritant and may be
corrosive; gum necrosis and gastrointestinal hemorrhage have
occurred. Acute encephalopathy has been reported following
bladder irrigation with alum solutions in the treatment of bladder
hemorrhage. Anecdotal evidence suggests that this practice should
be avoided for patients with renal insufficiency.
storage
Store in a cool, dry place in tightly closed containers. Stable under
normal temperatures and pressures. When kept for a long time at
60–65°C (or over sulfuric acid) potassium alum dodecahydrate
loses water, which is reabsorbed on exposure to air. It becomes
anhydrous at about 200°C.
Incompatibilities
Potassium alum is incompatible with strong oxidizing agents,
aluminum, copper, steel, and zinc. When it is dispensed in powders
with phenol, salicylates, or tannic acid, gray or green colors may be
developed owing to traces of iron in the alum.
Regulatory Status
GRAS listed. Included in the FDA Inactive Ingredients Database
(vaginal; suppository). Included in medicines licensed in the UK.
