Clove Oil
» Clove Oil is the volatile oil distilled with steam from the dried flower buds of Syzygium aromaticum (L.) Merr. and L. M. Perry (Fam. Myrtaceae). It contains not less than 85.0 percent (v/v) of total phenolic substances, chiefly eugenol (C10H12O2).
Packaging and storage— Preserve in well-filled, tight containers, and avoid exposure to excessive heat.
Labeling— The label states the Latin binomial name and, following the official name, the part of the plant source from which the article was derived.
Solubility in 70 percent alcohol— One volume dissolves in 2 volumes of 70 percent alcohol.
Specific gravity 841: between 1.038 and 1.060.
Angular rotation 781A It is optically inactive or slightly levorotatory; and the angular rotation is not greater than –1.5.
Refractive index 831: between 1.527 and 1.535 at 20.
Limit of phenol— Shake 1 mL of Oil with 20 mL of hot water: the water shows not more than a scarcely perceptible acid reaction with blue litmus paper. Cool the mixture, pass the water layer through a wetted filter, and treat the clear filtrate with 1 drop of ferric chloride TS: the mixture exhibits only a transient, grayish green color, but not a blue or violet color.
Assay— Pipet 10 mL of Oil into a suitable cassia flask, the neck of which is graduated from 0 mL to 6 mL at intervals of 0.1 mL. Add 75 mL of 1 N potassium hydroxide, shake the mixture for 5 minutes, and heat for 10 minutes in boiling water, shaking the flask at least 3 times during the heating. Remove the flask from the bath, and cool to room temperature. When the liquids have separated completely, add sufficient 1 N potassium hydroxide to raise the lower level of the oily layer within the graduated portion of the neck. After standing for 18 hours, the volume of the oily layer does not exceed 1.5 mL, indicating the presence in the Oil of not less than 85.0%, by volume, of total phenolic substances.
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Topic/Question Contact Expert Committee
Monograph Rick G. Schnatz
Manager, Compounding Pharmacy Expert Committee
(CRX05) Compounding Pharmacy05
USP32–NF27 Page 1207
Pharmacopeial Forum: Volume No. 27(4) Page 2796