Packaging and storage—
Preserve in single-dose or multiple-dose containers, preferably of Type I glass, protected from light.
Identification—
A:
Dilute a volume of Injection, equivalent to about 90 mg of codeine phosphate, with water to about 10 mL, add 1 drop of hydrochloric acid, and extract with three 10-mL portions of chloroform, discarding the chloroform extracts. Add 6 N ammonium hydroxide until the solution is alkaline, and extract with several 10-mL portions of chloroform. Evaporate the combined chloroform extracts on a steam bath to dryness, and dry at 80
for 4 hours: the IR absorption spectrum of a potassium bromide dispersion of the residue so obtained exhibits maxima at the same wavelengths as that of the codeine obtained by similarly treating 1 mL of a solution of
USP Codeine Phosphate RS (1 in 100).
Limit of morphine—
Diluted with water to a concentration of 5 mg of codeine phosphate per mL, it meets the requirements of the test for
Limit of morphine under
Codeine Phosphate.
Other requirements—
It meets the requirements under
Injections 
1
.
Assay—
Transfer an accurately measured volume of Injection, equivalent to about 75 mg of codeine phosphate, to a small separator, and add about 15 mL of water. Add 2 drops of phosphoric acid, and extract with four 10-mL portions of chloroform, collecting the chloroform extracts in a separator. Wash the combined chloroform extracts with 10 mL of water, and add the water wash to the first separator containing the sample. Discard the chloroform extracts. Proceed as directed in the
Assay under
Codeine Phosphate Tablets, beginning with “render the solution alkaline with 6 N ammonium hydroxide.” Each mL of 0.02 N sulfuric acid is equivalent to 8.128 mg of C
18H
21NO
3·H
3PO
4·½H
2O.
