C18H34O2 -- 282.5 -- 112-80-1
Action and use: Excipient.
Ph Eur
DEFINITION
(Z)-Octadec-9-enoic acid (C18H34O2; Mr 282.5), together with varying amounts of
saturated and other unsaturated fatty acids. A suitable antioxidant may be
added.
Content: 65.0 per cent to 88.0 per cent of C18H34O2.
CHARACTERS
Appearance: Clear, yellowish or brownish, oily liquid.
Solubility: Practically insoluble in water, miscible with alcohol and with
methylene chloride.
Relative density: About 0.892.
IDENTIFICATION
A. It complies with the test for acid value (see Tests).
B. It complies with the test for iodine value (see Tests).
C. It complies with the test for composition of fatty acids (see Tests).
Margaric acid: Maximum 0.2 per cent for oleic acid of vegetable origin and
maximum 4.0 per cent for oleic acid of animal origin.
TESTS
Appearance: The substance to be examined is not more intensely coloured than
reference solution.
Acid value: 195 to 204, determined on 0.5 g.
Iodine value: 89 to 105.
Peroxide value: Maximum 10.0.
Composition of fatty acids by Gas chromatography:
myristic acid: maximum 5.0 per cent;
palmitic acid : maximum 16.0 per cent;
palmitoleic acid : maximum 8.0 per cent;
stearic acid : maximum 6.0 per cent;
oleic acid : 65.0 per cent to 88.0 per cent;
linoleic acid : maximum 18.0 per cent;
linolenic acid : maximum 4.0 per cent;
fatty acids of chain length greater than C18: maximum 4.0 per cent.
Total ash: Maximum 0.1 per cent, determined on 2.00 g.
Oleic Acid is manufactured from fats and oils derived from edible sources, animal or
vegetable, and consists chiefly of (Z)-9-octadecenoic acid [CH3(CH2)7CH:CH(CH2)7COOH].
It may contain suitable stabilizers.
NOTE: Oleic Acid labeled solely for external use is exempt from the requirement that it
be prepared from edible sources.
Labeling: If it is for external use only, the labeling so indicates. Label it to
indicate whether it is derived from animal or vegetable sources. Indicate the names and
quantity of any added stabilizers.
Specific gravity: between 0.889 and 0.895.
Congealing temperature: between 3 and 10 for Oleic Acid derived from animal
sources; between 10 and 16 for Oleic Acid derived from vegetable sources.
Acid value: between 196 and 204, about 2 g, accurately weighed, being used.
Iodine value: between 85 and 95.
Residue on ignition: not more than 1 mg (about 0.01%), from a 10-mL portion.
Mineral acids: Shake 5 mL with an equal volume of water at a temperature of about
25 for 2 minutes, allow the liquids to separate, and filter the water layer through a
paper filter previously moistened with water: the filtrate is not reddened by the
addition of 1 drop of methyl orange.
Neutral fat or mineral oil: Boil 1 mL with about 500 mg of sodium carbonate and
30 mL of water in a 250-mL flask: the resulting solution, while hot, is clear or, at
most, opalescent.
REQUIREMENTS
Acid Value: Between 196 and 204.
Iodine Value: Between 83 and 103.
Lead: Not more than 0.1 mg/kg.
Residue on Ignition: Not more than 0.01%.
Saponification Value: Between 196 and 206.
Titer (Solidification Point): Not above 10°.
Unsaponifiable: Matter Not more than 2.0%.
Water: Not more than 0.4%.
