C8H8O3 152.15

Benzoic acid,2-hydroxy-,methyl ester.
Methyl salicylate [119-36-8].

Packaging and storage— Preserve in tight containers.

Labeling— Label it to indicate whether it was made synthetically or distilled from either of the plants mentioned above.

Solubility in 70percent alcohol— One volume of synthetic Methyl Salicylate dissolves in 7volumes of 70percent alcohol.One volume of natural Methyl Salicylate dissolves in 7volumes of 70percent alcohol,the solution having not more than a slight cloudiness.

Identification— Shake 1drop with about 5mLof water,and add 1drop of ferric chloride TS:the resulting mixture has a deep violet color.

Specific gravity á841ñ: between 1.180and 1.185for the synthetic variety;between 1.176and 1.182for the natural variety.

Angular rotation á781ñ— Synthetic Methyl Salicylate and that from betula are optically inactive.Methyl Salicylate from gaultheria is slightly levorotatory,the angular rotation not exceeding -1.5in a 100-mm tube.

Refractive index á831ñ: between 1.535and 1.538at 20.

Heavy metals,Method IIá231ñ: 20µg per g.

Organic volatile impurities,Method IVá467ñ: meets the requirements.

Assay— Place about 2g of Methyl Salicylate,accurately weighed,in a flask,add 40.0mLof 1Nsodium hydroxide VS,and boil gently under a reflux condenser for 2hours.Cool,rinse the condenser and the sides of the flask with a few mLof water,add phenolphthalein TS,and titrate the excess alkali with 1Nsulfuric acid VS.Perform a blank determination (see Residual Titrations underTitrimetry á541ñ).Each mLof 1Nsodium hydroxide corresponds to 152.2mg of C8H8O3.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3037

Phone Number:1-301-816-8379