631. Adeps Lanae Hydrosus.—Lanolin. Hydrous Wool-Fat.
The purified fat of the wool of sheep, Ovis aries Linné (Fam. Bovidae), mixed with not more than 30 per cent. of water. For Tests see U.S.P.
DESCRIPTION.—A yellowish-white unctuous mass. Faint, peculiar odor. Insoluble in water, but miscible with twice its weight. Melts at about 40°C. (104°F.). Adeps Lanae, U. S., is the above freed from water.
CONSTITUENTS.—Cholesterin, palmitin, olein, the first mentioned being largely represented.
USES.—As an inunction and vehicle for substances the medicinal action of which can be obtained by local application. It is employed in several official ointments.
631a. HYDROCARBON FATS AND OILS.—(Petrolatum, etc.).
DESCRIPTION, SOURCE, ETC.—As a most valuable addition to the list of ointment bases and oleaginous liquids there has been officially recognized: Petrolatum album (White Petrolatum); Petrolatum Liquidum (oil); Petrolatum Molle (soft Petrolatum); and Petrolatum Spissum (Hard Petrolatum). These are mixtures of the harder and softer members of the paraffin series of hydrocarbons, having different melting and congealing points, etc. Hard paraffin consists chiefly of hydrocarbons ranging from C20H42 to C30H62; soft paraffin consists chiefly of C15H32 to C20H42; liquid consists chiefly of heptane, C7H16, and octane, C8H18.
USE.—As a vehicle for medicinal substances applied locally. As such it is much less permeable through the skin than other fats.