Packaging and storage— Preserve in single-dose or in multiple-dose containers,preferably of Type Iglass.Protect from light.

USP Reference standards á11ñ— USP Aurothioglucose RS.

Identification— Transfer a volume of Injectable Suspension,equivalent to about 200mg of aurothioglucose,to a centrifuge separator containing 20mLof ethyl acetate and 50mLof water.Shake the mixture thoroughly,and centrifuge until the liquid phases have been clearly separated.Withdraw the lower,aqueous phase,and filter,discarding the first 10mLof the filtrate.Collect the filtrate in a glass-stoppered vessel,and proceed as directed in Identificationtest Aunder Aurothioglucose,beginning with “apply 10µLof this solution.”

Other requirements— It meets the requirements under Injections á1ñ.

Assay— Transfer with a pipet,calibrated to contain rather than to deliver,an accurately measured volume of Injectable Suspension,equivalent to about 200mg of aurothioglucose,to a beaker containing 400mLof acetone.Wash the pipet into the beaker with a small quantity of acetone,mix,allow the solids to settle,and decant the supernatant through a filter.Wash the solids with another 400-mLportion of acetone,and repeat the decantation.Transfer the solids to the filter with the aid of acetone,then transfer the filter and its contents to a short-necked,300-mL Kjeldahl flask,add 5mLof water,and proceed as directed in the Assayunder Gold Sodium Thiomalate,beginning with “add 20mLof nitric acid.”The weight of gold so obtained,multiplied by 1.991,represents the weight of C6H11AuO5Sin the portion of Injectable Suspension taken.

Expert Committee:(PA2)Pharmaceutical Analysis 2

USP28–NF23Page 203

Phone Number:1-301-816-8139