C18H21NO3·H3PO4·½H2O 406.37

Morphinan-6-ol,7,8-didehydro-4,5-epoxy-3-methoxy-17-methyl-,(5a,6a)-,phosphate (1:1)(salt),hemihydrate.
7,8-Didehydro-4,5a-epoxy-3-methoxy-17-methylmorphinan-6a-ol phosphate (1:1)(salt)hemihydrate [41444-62-6].

Anhydrous 397.37 [52-28-8].

Packaging and storage— Preserve in tight,light-resistant containers.Store at 25,excursions permitted between 15and 30.

USP Reference standards á11ñ— USP Codeine Phosphate RS.

Identification—

Acidity— Dissolve 100mg in 20mLof water,and titrate with 0.010Nsodium hydroxide to a pHof 5.4,using a pHmeter:not more than 1.0mLof 0.010Nsodium hydroxide is required.

Water,Method Iá921ñ: not more than 3.0%.

Chloride— To 10mLof a solution (1in 100),acidified with nitric acid,add a few drops of silver nitrate TS:no opalescence is produced immediately.

Sulfate— To 10mLof a solution (1in 100)add a few drops of barium chloride TS:no turbidity is produced immediately.

Limit of morphine— Dissolve about 50mg of potassium ferricyanide in 10mLof water,and add 1drop of ferric chloride TSand 1mLof a solution of Codeine Phosphate (1in 100):no blue color is produced immediately.

Chromatographic purity— Using Codeine Phosphate,proceed as directed in the test for Chromatographic purityunder Codeine,except to use a mixture of 0.01Nhydrochloric acid and dehydrated alcohol (4:1),instead of dehydrated alcohol,to prepare Solution A,Solution B,and Solution C.

Assay— Dissolve about 1g of Codeine Phosphate,accurately weighed,in 50mLof glacial acetic acid,warming slightly if necessary to effect solution,and titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 39.74mg of C18H21NO3·H3PO4.

Expert Committee:(PA2)Pharmaceutical Analysis 2

USP28–NF23Page 535

Phone Number:1-301-816-8139