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Category  Expectorant; antiseptic; pharmaceutic aid.

             Storax is a balsam obtained from the trunk of Liquidambar orientalis Mill., known in commerce as Levant Storax, or of Liquidambar styraciflua L. known in commerce as American Storax (Family Altingiaceae).

Origin of plant  Levant Storax-yielding plants are native to East Aegean Islands to west and southwest Turkey.  An American Storax-yielding plant is native to North America, Central America and northern South America.

Constituents  Levant Storax contains styrene, cinnamic acid and its esters such as cinnamyl cinnamate or styracin. It also contains triterpene acids, vanillin, and aromatic alcohols.  American Storax contains styresinol, both free and as cinnamic acid esters, free cinnamic acid, styracin, vanillin, styrol, etc.

Description  Odour balsamic, characteristic; taste acrid.  Levant Storax:  semiliquid, greyish to greyish brown, opaque mass depositing on a heavy dark brown layer.  American Storax:  semisolid or sometimes solid mass, softened when gently warmed. 

Solubility  Insoluble in water.  Soluble, usually incompletely, in an equal weight of warm ethanol.  Soluble in acetone, in carbon disulfide, and in ether, some insoluble residue usually remaining. 

Packaging and storage  Storax shall be kept in well-closed containers, at a temperature not exceeding 25°.

Loss on drying  Not more than 20.0 per cent w/w after drying 2 g at 105° for 2 hours (Appendix 4.15).

Ethanol-insoluble substances  Not more than 5.0 per cent w/w, determined by the following method.  Accurately weigh about 10 g of mixed Storax in a beaker, heat at 105° for 30 minutes, take up the residue in 100 mL of hot ethanol, filter through counter-balanced filters or a tared filter crucible, and wash the residue with small portions of hot ethanol until the last washing is colourless or practically so.  Dry the residue at 105° for 1 hour and weigh.

Ethanol-soluble substances  Not less than 70.0 per cent w/w, determined by the following method.  Evaporate the combined ethanol filtrate and washings obtained in the test for Ethanol-insoluble substances at a temperature not exceeding 60°.  Dry the residue at 105° for 1 hour and weigh the yellow to brown residue of purified Storax so obtained.

Acid value, Saponification value, Cinnamic acid  The purified Storax obtained in the test for Ethanol-soluble substances meets the requirements of the following tests.
Acid value  50 to 85 for Levant Storax and 36 to 85 for American Storax, determined by the following method.  Dissolve about 1 g of the purified Storax, accurately weighed, in 50 mL of neutralized ethanol, add 0.5 mL of phenolphthalein TS, and titrate with 0.5M sodium hydroxide VS.
Saponification value  160 to 200, determined by the following method.  Place about 2 g of the purified Storax, accurately weighed, in a 250-mL flask, mix it with 50 mL of petroleum ether (boiling range, 40° to 60°), add 25.0 mL of 0.5 M ethanolic potassium hydroxide VS, and allow the mixture to stand for 24 hours with frequent agitation.  Then add 0.5 mL of phenolphthalein TS and titrate the excess alkali with 0.5 M hydrochloric acid VS.
Cinnamic acid  Not less than 25 per cent of the weight of purified Storax taken, determined by the following method.  Add about 2 g of the purified Storax, accurately weighed, to 25 mL of 0.5 M ethanolic potassium hydroxide, and boil the mixture for 1 hour under a reflux condenser.  Add 0.5 mL of phenolphthalein TS, neutralize with 0.25 M sulfuric acid, and evaporate the ethanol on a water-bath.  Dissolve the residue in 50 mL of water, and shake the solution with 20 mL of ether.  Shake the separated ether with 5 mL of water, adding the washing to the aqueous solution, and reject the ether extract.  Add to the aqueous solution 10 mL of dilute sulfuric acid, and shake with four 20-mL portions of ether.  Wash the combined ether extracts with 5 mL of water, rejecting the aqueous washing, transfer to a flask, and distil off the ether.  Add to the residue 100 mL of water and boil the mixture vigorously for 15 minutes under a reflux condenser.  Filter while hot and allow the filtrate to cool to about 25°:  white crystals of cinnamic acid separate.  Collect and dry the cinnamic acid by vacuum filtration.  Repeat the extraction of the residue twice by boiling each time under a reflux condenser, as previously described, with the filtrate from the preceding crystallization, and collect the additional cinnamic acid in the same crucible.  Finally wash the cinnamic acid with two 10-mL portions of ice-cold water, dry at 80°, and weigh.  A portion of the acid recrystallized from hot water melts between 134° and 135°. 
To about 50 mg of the cinnamic acid obtained as directed above add 5 mL of 1 M sulfuric acid, heat, and add potassium permanganate TS:  the odour of benzaldehyde is perceptible.