Monograph: |
LANOLIN ( Wool Fat )
Some pharmacopoeias include Hydrous Wool Fat which is
prepared by the addition of water to wool fat.
US also includes under the tide Modified Lanolin a grade that
has been processed to reduce the contents of free lanolin al-
cohols and detergent and pesticide residues.
A purified anhydrous waxy substance obtained from the wool
of the sheep, Ovis aries (Bovidae). It is a pale yellow unctu-
ous substance with a characteristic odour, melted wool fat is
a clear or almost clear, yellow liquid. Drop point and melting
range 38Β° to 44Β°. It may contain a suitable antoxidant. 10 g
absorbs not less than 20 mL of water.
Practically insoluble in water; sparingly soluble in cold alco-
hol, slightly soluble in boiling alcohol: soluble to freely solu-
ble in ether; freely soluble in chloroform: it forms an
opalescent solution in petroleum spirit. Store at temperature
not exceeding 25Β°.
Wool fat is used in the formulation of water-in-oil creams and
ointments. When mixed with a suitable vegetable oil or with
soft paraffin it gives emollient creams which penetrate the
skin. It can absorb about 30% of water.
Derivatives and modifications of wool fat include poloxyl lan-
olin (ethoxylaled lanolin), isopropyl lanolate, lanolin oil. and
lanolin wax. Hydrogenated wool fat (hydrogenated lanolin) is
a mixture of higher aliphatic alcohols and sterols obtained
from the hydrogenation of wool fat.
Hydrous wool fat (hydrous lanolin) is an ointment basis pre-
pared by the addition of water to wool fat. The Ph. Eur. spec-
ifies wool fat 75% and water 25%.
Wool fat can cause sensitivity reactions.
Lanolin treated to remove both detergent and natural free fat-
ty alcohols reduced the incidence of hypersensitivity in lano-
lin-sensitive patients to almost zero.
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