Chemical Properties
clear to white solid
General Description
Dark brown, green, amber or white odorless thick liquid. Floats on water.
Reactivity Profile
Petrolatum is unreactive in most circumstances.
Health Hazard
LIQUID: Irritating to eyes.
Definition
Petrolatum is a complex combination of hydrocarbons obtained as a semi-solid from dewaxing paraffinic residual oil. It consists predominantly of saturated crystalline and liquid hydrocarbons having carbon numbers predominantly greater than C25.
Production Methods
Petrolatum is manufactured from the semisolid residue that remains
after the steam or vacuum distillation of petroleum.This residue
is dewaxed and/or blended with stock from other sources, along
with lighter fractions, to give a product with the desired consistency.
Final purification is performed by a combination of high-pressure
hydrogenation or sulfuric acid treatment followed by filtration
through adsorbents. A suitable antioxidant may be added.
Brand name
Moroline (Schering-Plough HealthCare).
Flammability and Explosibility
Notclassified
Pharmaceutical Applications
Petrolatum is mainly used in topical pharmaceutical formulations as
an emollient-ointment base; it is poorly absorbed by the skin.
Petrolatum is also used in creams and transdermal formulations and
as an ingredient in lubricant formulations for medicated confectionery
together with mineral oil.
Therapeutically, sterile gauze dressings containing petrolatum
may be used for nonadherent wound dressings or as a packing
material.Petrolatum is additionally widely used in cosmetics and
in some food applications.
Safety
Petrolatum is mainly used in topical pharmaceutical formulations
and is generally considered to be a nonirritant and nontoxic
material.
Animal studies, in mice, have shown petrolatum to be nontoxic
and noncarcinogenic following administration of a single subcutaneous
100 mg dose. Similarly, no adverse effects were observed in a
2-year feeding study with rats fed a diet containing 5% of
petrolatum blends.
Although petrolatum is generally nonirritant in humans following
topical application, rare instances of allergic hypersensitivity
reactions have been reported,as have cases of acne, in susceptible individuals following repeated use on facial skin.
However, given the widespread use of petrolatum in topical
products, there are few reports of irritant reactions. The allergic
components of petrolatum appear to be polycyclic aromatic
hydrocarbons present as impurities. The quantities of these
materials found in petrolatum vary depending upon the source
and degree of refining. Hypersensitivity appears to occur less with
white petrolatum and it is therefore the preferred material for use in
cosmetics and pharmaceuticals.
Petrolatum has also been tentatively implicated in the formation
of spherulosis of the upper respiratory tract following use of a
petrolatum-based ointment packing after surgery,and lipoid
pneumonia following excessive use in the perinasal area.Other
adverse reactions to petrolatum include granulomas (paraffinomas)
following injection into soft tissue.Also, when taken orally,
petrolatum acts as a mild laxative and may inhibit the absorption of
lipids and lipid-soluble nutrients.
Petrolatum is widely used in direct and indirect food applications.
In the USA, the daily dietary exposure to petrolatum is
estimated to be 0.404 mg/kg body-weight.
For further information see Mineral Oil and Paraffin.
storage
Petrolatum is an inherently stable material owing to the unreactive
nature of its hydrocarbon components; most stability problems
occur because of the presence of small quantities of impurities. On
exposure to light, these impurities may be oxidized to discolor the
petrolatum and produce an undesirable odor. The extent of the
oxidation varies depending upon the source of the petrolatum and
the degree of refinement. Oxidation may be inhibited by the
inclusion of a suitable antioxidant such as butylated hydroxyanisole,
butylated hydroxytoluene, or alpha tocopherol.
Petrolatum should not be heated for extended periods above the
temperature necessary to achieve complete fluidity (approximately
70°C).
Petrolatum may be sterilized by dry heat. Although petrolatum
may also be sterilized by gamma irradiation, this process affects the
physical properties of the petrolatum such as swelling, discoloration,
odor, and rheological behavior.
Petrolatum should be stored in a well-closed container, protected
from light, in a cool, dry place.
Incompatibilities
Petrolatum is an inert material with few incompatibilities.
Regulatory Status
GRAS listed. Accepted for use in certain food applications in many
countries worldwide. Included in the FDA Inactive Ingredients
Database (ophthalmic preparations; oral capsules and tablets; otic,
topical, and transdermal preparations). Included in nonparenteral
medicines licensed in the UK. Included in the Canadian List of
Acceptable Non-medicinal Ingredients.
