Storax
»Storax is a balsam obtained from the trunk of Liquidambar orientalisMiller,known in commerce as Levant Storax,or of Liquidambar styracifluaLinné,known in commerce as American Storax (Fam.Hamamelidaceae).
Packaging and storage— Preserve in well-closed containers.
Loss on drying á731ñ— Dry about 2g,accurately weighed,at 105for 2hours:it loses not more than 20.0%of its weight.
Alcohol-insoluble substances— Accurately weigh about 10g of mixed Storax in a beaker,heat at 105for 30minutes,take up the residue in 100mLof hot alcohol,filter through counter-balanced filters or a tared filter crucible,and wash the residue with small portions of hot alcohol until the last washing is colorless or practically so:the weight of the residue so obtained,after drying at 105for 1hour,does not exceed 5.0%of the weight of Storax taken.
Alcohol-soluble substances— Evaporate the combined alcohol filtrate and washings obtained in the test for Alcohol-insoluble substancesat a temperature not exceeding 60,and dry the residue at 105for 1hour:the weight of the yellow to brown residue of purified Storax so obtained is not less than 70.0%of the weight of the Storax taken.
Acid value,Saponification value,Cinnamic acid— The purified Storax obtained in the test for Alcohol-soluble substancesmeets the requirements of the following tests.
Acid value á401ñ —Dissolve about 1g of the purified Storax,accurately weighed,in 50mLof neutralized alcohol,add 0.5mLof phenolphthalein TS,and titrate with 0.5Nsodium hydroxide VS:the acid value is between 50and 85for Levant Storax and between 36and 85for American Storax.
Saponification value á401ñ —Place about 2g of the purified Storax,accurately weighed,in a 250-mLflask,mix it with 50mLof solvent hexane,add 25.0mLof 0.5Nalcoholic potassium hydroxide VS,and allow the mixture to stand for 24hours with frequent agitation.Then add 0.5mLof phenolphthalein TS,and titrate the excess alkali with 0.5Nhydrochloric acid VS:the saponification value thus determined is between 160and 200.
Cinnamic acid— Add about 2g of the purified Storax,accurately weighed,to 25mLof 0.5Nalcoholic potassium hydroxide,and boil the mixture for 1hour under a reflux condenser.Add 0.5mLof phenolphthalein TS,neutralize with 0.5Nsulfuric acid,and evaporate the alcohol on a steam bath.Dissolve the residue in 50mLof water,and shake the solution with 20mLof ether.Shake the separated ether with 5mLof water,adding the washing to the water solution,and reject the ether extract.Add to the water solution 10mLof diluted sulfuric acid,and shake with four 20-mLportions of ether.Wash the combined ether extracts with 5mLof water,rejecting the water washing,transfer to a flask,and distill off the ether.Add to the residue 100mLof water,and boil the mixture vigorously for 15minutes 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-mLportions of ice-cold water,dry at 80,and weigh.The weight of the cinnamic acid so obtained is not less than 25.0%of the weight of purified Storax taken.Aportion of the acid recrystallized from hot water melts between 134and 135.
To about 50mg of the cinnamic acid obtained as directed above add 5mLof 2Nsulfuric acid,heat,and add potassium permanganate TS:the odor of benzaldehyde is perceptible.
Organic volatile impurities,Method IVá467ñ: meets the requirements.
Auxiliary Information— Staff Liaison:Elena Gonikberg,Ph.D.,Scientist
Expert Committee:(PA4)Pharmaceutical Analysis 4
USP28–NF23Page 1804
Phone Number:1-301-816-8251