A: Infrared Absorption 197K.

B: Ultraviolet Absorption 197U—

Solution: 100 µg per mL.

Medium: dilute hydrochloric acid (1 in 120).

Test solution: 100 mg per mL, in chloroform. Its specific rotation does not differ from that of the similarly prepared solution of USP Dextromethorphan RS by more than 1.0%.

Standard solution— Transfer about 50 mg of N,N-dimethylaniline to a 100-mL volumetric flask, add 70.0 mL of water, insert the stopper tightly, shake for 20 minutes using a mechanical wrist-action shaker or equivalent, dilute with water to volume, and mix. Transfer 1.0 mL to a 100-mL volumetric flask, dilute with water to volume, transfer 1.0 mL of this solution to a 25-mL volumetric flask, and add 19 mL of water.

Test solution— Transfer about 500 mg of Dextromethorphan, accurately weighed, to a 25-mL volumetric flask, add 19 mL of water and 1 mL of 3 N hydrochloric acid, dissolve by warming on a steam bath, and cool.

Procedure— Add 2 mL of 1 N acetic acid and 1 mL of sodium nitrite solution (1 in 100) to the Test solution, dilute with water to volume, and mix. This solution shows no more color than the straw yellow to greenish yellow color of the solution obtained from the Standard solution similarly treated: not more than 0.001% of N,N-dimethylaniline is found.

(Official January 1, 2007)