Hard Paraffin
A mixture of solid saturated hydrocarbons obtained from pe-
troleum.
It is a colourless or white, odourless, translucent solid, show-
ing a crystalline structure, and is slightly greasy to the touch,
The melted substance is free from fluorescence in daylight. It
has a congealing range of 47Β° to 65Β°.
Practically insoluble in water and in alcohol; freely soluble in
chloroform, in dichloromethane. in ether, in volatile oils, and
in most warm fixed oils: slightly soluble in dehydrated alco-
hol. An alcoholic extract is neutral to litmus. Protect from
light.
Synthetic Paraffin is a very hard odourless white
wax containing mostly long-chain, unbranched, saturated hy-
drocarbons, with a small amount of branched hydrocarbons.
The average molecular weight may range from 400 lo 1400.
Hard paraffin is employed principally as a stiffening ingredi-
ent in ointment bases. It is also used in creams, and as a coat-
ing for capsules and tablets.
A variety of hard paraffin (m.p. 43Β° to 46Β°) is employed in
physiotherapy in the form of paraffin-wax baths for the relief
of pain in inflamed joints and sprains.
The injection of paraffins may produce granulomatous reac-
tions.
Liquid Paraffin
Liquid paraffin is a mixture of liquid saturated hydrocarbons
obtained from petroleum. The USP permits a suitable stabilis-
er.
It is a transparent, colourless, odourless, or almost odourless.
oily liquid, free, or practically free. from fluorescence by day-
light. Practically insoluble in water, in ether, and in hydrocar-
bons: practically insoluble to slightly soluble in alcohol:
miscible with fixed oils (except castor oil) and soluble in vol-
atile oils. Store in airtight containers. Protect from light.
Light Liquid Paraffin
(Topical Light Mineral Oil)
Light liquid paraffin is a mixture of liquid saturated hydrocar-
bons obtained from petroleum. The USNF permits a suitable
stabiliser. It has similar characteristics to Liquid Paraffin,
but a lower kinematic viscosity.
Adverse Effects and Precautions
Excessive dosage by mouth, or rectum, may result in anal
seepage and irritation. Liquid paraffin is absorbed to a slight
extent and may give rise to foreign-body granulomatous reac-
tions. Similar reactions have followed the injection of liquid
paraffin and may be considerably delayed in onset. Injection
may also cause vasospasm and prompt surgical removal may
be required to prevent severe damage, Lipoid pneumonia has
been reported following the aspiration of liquid paraffin.
Chronic ingestion of liquid paraffin may rarely be associated
with impaired absorption of fat-soluble vitamins and possibly
other compounds. It should not be used when abdominal pain,
nausea, or vomiting is present. Prolonged use should be
avoided. Also it should not be used in children under 3 years
of age.
Haematological changes and deposition of food grade liquid
paraffins in the liver, spleen, and lymph nodes has occutred
during feeding studies in rats.
Uses and Administration
Taken internally, liquid paraffin acts as a lubricant and. since
it keeps the stools soft. it has been used in the symptomatic
treatment of constipation, although its use is gener-
ally not recommended. Up to 45 mL has been given daily by
mouth, usually in the evening but should not be taken imme-
diately before going to bed. Liquid paraffin is an ingredient of
several preparations that contain other laxatives such as cas-
cara. magnesium hydroxide, or phenolphthalein. It has also
been given as an enema in a usual dose of 120 mL.
Externally, liquid paraffin may be used as an ingredient of
ointment bases, as an emollient and cleanser in certain skin
conditions, and as an ophthalmic lubricant in the management
of dry eye.
Light liquid paraffin has similar uses to liquid paraffin.
White Soft Paraffin
Vaselinum Album; in Great Britain the name 'Vaseline' is a
trade-mark.
White soft paraffin is bleached yellow soft paraffin. The USP
permits a suitable stabiliser.
Yellow Soft Paraffin
A purified semi-solid mixture of hydrocarbons obtained from
petroleum. It is a pale yellow to yellow or light amber-col-
oured, translucent, soft, unctuous mass, not more than slightly
fluorescent by daylight even when melted, and odourless
when nibbed on the skin. The USP permits a suitable stabilis-
er. The BP has a drop point of 42Β° to 60Β°. The USP Ms a m.p.
of 38Β° to 60Β°.
Practically insoluble in water and in alcohol: soluble in car-
bon disulphide. chloroform, ether, petroleum spirit, and most
fixed and volatile oils, the solutions sometimes showing a
slight opalescence. Protect from light.
Adverse Effects
Adverse effects of white soft paraffin or yellow soft paraffin
are rare when used in topical preparations, but sensitivity re-
actions and acne have been reported following topical use.
Granulomatous reactions following absorption or injection
and lipoid pneumonia following aspiration have occurred.
A report of burns to the scalp, face, arid hands in 5 patients
who accidentally ignited their hair following the application
of paraffin-based hair grease. Four patients suffered inhala-
tion injury, 2 of whom required intubation.
Hypersensitivity. Studies on the allergenicity of white soft
paraffin and yellow soft paraffin products. Considering
their widespread use there are very few reports of sensitivity;
white soft paraffin is generally less sensitizing than yellow
soft paraffin, although allergenicity differs from product to
product. The allergenic components are probably polycyclic
aromatic hydrocarbons present as impurities and quantities
found in a particular paraffin depend on the source and puri-
fication method. Only the purest forms should be used in
pharmaceuticals, cosmetics, and for patch testing, and highly
purified white soft paraffin is preferred to yellow soft
paraffin.
Uses and Administration
Soft paraffin is used as an ointment basis and as an emollient
in the management of skin disorders. It is not readily ab-
sorbed by the skin. Sterile dressings containing soft paraffin
are used for wound dressing and as a packing material. Soft
paraffin is also included in ointments used as ophthalmic lu-
bricants in the management of dry eye . Application of soft
paraffin has also been used for the eradication of
pubic lice from the eyelashes .