» Methyl Salicylate is produced synthetically or is obtained by maceration and subsequent distillation with steam from the leaves of Gaultheria procumbens Linne (Fam. Ericaceae) or from the bark of Betula lenta Linne (Fam. Betulaceae). It contains not less than 98.0 percent and not more than 100.5 percent of C8H8O3.
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 70 percent alcohol One volume of synthetic Methyl Salicylate dissolves in 7 volumes of 70 percent alcohol. One volume of natural Methyl Salicylate dissolves in 7 volumes of 70 percent alcohol, the solution having not more than a slight cloudiness.
Identification Shake 1 drop with about 5 mL of water, and add 1 drop of ferric chloride TS: the resulting mixture has a deep violet color.
Specific gravity 841: between 1.180 and 1.185 for the synthetic variety; between 1.176 and 1.182 for the natural variety.
Angular rotation 781 Synthetic Methyl Salicylate and that from betula are optically inactive. Methyl Salicylate from gaultheria is slightly levorotatory, the angular rotation not exceeding 1.5 in a 100-mm tube.
Refractive index 831: between 1.535 and 1.538 at 20.
Heavy metals, Method II 231: 20 µg per g.
Assay Place about 2 g of Methyl Salicylate, accurately weighed, in a flask, add 40.0 mL of 1 N sodium hydroxide VS, and boil gently under a reflux condenser for 2 hours. Cool, rinse the condenser and the sides of the flask with a few mL of water, add phenolphthalein TS, and titrate the excess alkali with 1 N sulfuric acid VS. Perform a blank determination (see Residual Titrations under Titrimetry 541). Each mL of 1 N sodium hydroxide corresponds to 152.2 mg of C8H8O3.
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USP32NF27 Page 1281
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.