Polacrilin potassium

• USP–NFPolacrilin Potassium

Amberlite IRP88; methacrylic acid polymer with divinylbenzene, potassium salt; polacrilinum kalicum

Potassium salt of a cross-linked copolymer of methacrylic acid and divinylbenzene · [—]

Polymer, mixture or material of variable composition — no single molecular formula applies.

Disintegrant

Typical concentrations: 2–10% · Dosage forms: Solid

Used mainly as a tablet disintegrant, typically at 2–10% w/w, in both direct compression and wet granulation. Its strong swelling on contact with water gives rapid disintegration without forming a gel. It is not normally used for its ion-exchange properties.

A cation-exchange resin made from methacrylic acid cross-linked with divinylbenzene, in the potassium salt form. It is supplied as a fine, free-flowing, cream-coloured powder with little or no odour or taste.

Physical form

free-flowing, cream-coloured fine powder; odourless and almost tasteless

Potassium content

about 21–25% (dried basis)

Solubility

insoluble in water and in most organic solvents; swells rapidly in water

Type

weakly acidic cation-exchange resin (carboxylate functional groups)

Stable. Store in a well-closed container in a cool, dry place.

Incompatible with strong oxidising agents. As an ion-exchange resin it may bind cationic drugs and exchange potassium with other cations, which can affect drug release.

Made by suspension copolymerisation of methacrylic acid with divinylbenzene as the cross-linker; the resin is then neutralised with potassium hydroxide, washed, dried and milled.

Used in oral solid dosage forms and regarded as non-toxic; being an insoluble, high-molecular-weight polymer it is not absorbed from the gastrointestinal tract. The potassium it contains should be considered for patients on potassium restriction only when large amounts are taken.

Observe normal precautions for the quantity handled. Avoid generating dust; eye protection, gloves and a dust mask are recommended.

Included in the FDA Inactive Ingredient Database (oral capsules and tablets).

Polacrilex resin; sodium polystyrene sulfonate; cholestyramine resin.

Polacrilin potassium is relatively insensitive to the lubricant and to compression force, but because it is an ion exchanger, compatibility with ionic (especially basic) drugs should be checked. The related hydrogen-form resin (polacrilex) is used to bind and mask the taste of bitter cationic drugs and in nicotine gum.