Identification
A:
Dilute a volume of Injection,equivalent to about 50mg of chlorpheniramine maleate,with dilute hydrochloric acid (1in 1000)to 25mL,and proceed as directed under
IdentificationOrganic Nitrogenous Bases á181ñ,beginning with Transfer the liquid to a separator.The Injection meets the requirements of the test.
B:
Evaporate a volume of Injection,equivalent to about 25mg of chlorpheniramine maleate,on a steam bath to dryness,and dry the residue at 105

for 1hour:it melts between 128

and 135

.
Assay
Proceed with Injection as directed under
Salts of Organic Nitrogenous Bases á501ñ,to prepare the solution employed for the determination of the absorbance,
AU,at 264nm.For the determination of
AS,dissolve about 25mg of
USP Chlorpheniramine Maleate RS,accurately weighed,in 20mLof dilute sulfuric acid (1in 350),and treat this solution the same as the portion of Injection being assayed.Calculate the quantity,in mg,of C
16H
19ClN
2·C
4H
4O
4in each mLof the Injection taken by the formula:
(C/V)(AU/AS),
in which
Cis the weight,in mg,of
USP Chlorpheniramine Maleate RSin the
Standard preparation,and
Vis the volume,in mL,of Injection taken.