White soft paraffin

• BPWhite Soft Paraffin
• JPWhite Petrolatum
• Ph. Eur.Paraffin, White Soft
• USP–NFWhite Petrolatum

paraffinum molle album; white petrolatum; white petroleum jelly; vaselinum album

Purified and wholly or nearly decolourised semisolid mixture of hydrocarbons obtained from petroleum · [8009-03-8]

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

Semi-solid base, emollient

Typical concentrations: 10–30% creams · up to 100% ointments · Dosage forms: Semi-solid

Used mainly as an emollient, occlusive ointment base and in creams and other topical emulsions; it is also used in ophthalmic ointments, transdermal systems and cosmetics. Typical concentrations: emollient creams 10–30%; topical emulsions 4–25%; topical ointments up to 100%.

A white or almost white, translucent, soft, unctuous mass that is odourless and tasteless; when melted it may show a slight fluorescence in daylight. It is more completely decolourised than yellow soft paraffin.

Melting range

about 38–60 °C (drop point varies with grade)

Consistency (cone penetration)

grade-dependent, typically 100–300 (0.1 mm units)

Solubility

soluble in chloroform, ether, light petroleum and most fixed and volatile oils; practically insoluble in water, ethanol and glycerin

Composition

a colloidal system of solid, mainly microcrystalline and branched hydrocarbons in liquid hydrocarbons

Inherently stable because its components are unreactive, but traces of impurities may oxidise on exposure to light and air, causing discolouration and an unpleasant odour; an antioxidant such as butylated hydroxytoluene or tocopherol may be added. It can be sterilised by dry heat. Store in a well-closed container, protected from light, in a cool, dry place.

An inert material with few incompatibilities.

Prepared from the semisolid residue left after distillation of petroleum, which is dewaxed or blended with lighter fractions to give the required consistency and then purified and decolourised (for example by hydrogenation or by treatment with acid and adsorbent clays) more extensively than the yellow grade.

Used widely on the skin and regarded as non-toxic and non-irritant; occasional hypersensitivity reactions have been attributed to impurities. Purity requirements limit polycyclic aromatic hydrocarbons. Dressings and clothing soaked with paraffin-based emollients are a fire hazard, as they ignite easily from naked flames or cigarettes.

Observe normal precautions for the quantity handled. It is combustible; take care when melting large quantities.

Permitted as a food additive in the USA. Included in the FDA Inactive Ingredient Database (ophthalmic, otic, oral, rectal, topical, transdermal and vaginal preparations) and in non-parenteral medicines licensed in Europe.

Hard paraffin; liquid paraffin; yellow soft paraffin; petrolatum and lanolin alcohols.

Its occlusive film reduces transepidermal water loss, which underlies its value as an emollient and its ability to enhance the penetration of some drugs. Its rheology changes with temperature and shear, so cooling rate and mixing during manufacture affect the consistency of the final ointment.