Packaging and storage— Preserve in well-closed containers.

Loss on drying á731ñ— Dry it at 105for 2hours:it loses not more than 0.5%of its weight.

Loss on ignition á733ñ— Transfer about 1g,previously dried and accurately weighed,to a tared platinum or porcelain crucible,and ignite at 980±25for 1hour:it loses not more than 2.0%of its weight.

Acid-soluble substances— Digest 10.0g with 50mLof 0.5Nhydrochloric acid at 70for 15minutes,and filter.Wash the residue,adding the washings to the filtrate,to obtain a total volume of 100mL.Evaporate at 110in a tared porcelain dish to dryness:the weight of the dried residue so obtained does not exceed 200mg (2.0%).

Water-soluble substances— Place 12.5g in a 500-mLconical flask,add 250mLof water,and shake for 2hours at room temperature.Filter with the aid of vacuum,and again filter if necessary to obtain a clear filtrate.Evaporate in a tared platinum or porcelain dish,and dry at 110:the weight of the residue does not exceed 25mg (0.2%).

Leachable arsenic— Transfer 10.0g to a 250-mLbeaker,add 50mLof 0.5Nhydrochloric acid,cover with a watch glass,and heat at 70for 15minutes.Cool,and decant through a Whatman No.3filter paper into a 100-mLvolumetric flask.Wash the slurry with three 10-mLportions of water,preheated to 70,dilute with water to volume,and mix:a 3.0-mLportion of this solution meets the requirements under Arsenic,Method Iá211ñ.The limit is 0.001%.

Leachable lead— A10.0-mLportion of the solution prepared in the test for Leachable arsenicmeets the requirements under Lead á251ñ,10mLof Diluted Standard Lead Solutionbeing used for the control.The limit is 0.001%.

Limit of nonsiliceous substances— Transfer about 200mg,accurately weighed,to a tared platinum crucible,add 5mLof hydrofluoric acid and 2drops of dilute sulfuric acid (1in 2),and evaporate gently to dryness.Cool,add 5mLof hydrofluoric acid,evaporate again to dryness,and ignite to constant weight:the weight of the residue so obtained does not exceed 50mg.

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 3073

Phone Number:1-301-816-8262