Chlorpheniramine Maleate Oral Solution
(Monograph under this new title—to become official June 1,2005)
(Current monograph title is Chlorpheniramine Maleate Syrup)
»Chlorpheniramine Maleate Oral Solution contains not less than 90.0percent and not more than 110.0percent of the labeled amount of chlorpheniramine maleate (C16H19ClN2·C4H4O4).
Packaging and storage— Preserve in tight,light-resistant containers.
Identification—
A: Evaporate the remaining extract from the Assayon a steam bath to a small volume,then transfer it to a smaller,more suitable vessel,and evaporate just to the point where hexane vapors are no longer perceptible.Transfer the oily residue,with the aid of four 3-mLportions of dimethylformamide,to a suitable glass-stoppered graduated cylinder,dilute with dimethylformamide to 15.0mL,and mix:the optical rotation of the solution so obtained,in a 100-mm tube,after correcting for the blank,is not more than +0.01(distinction from dexchlorpheniramine maleate).
B:Ultraviolet Absorption á197Uñ—
Solution: the solution employed for measurement of absorbance in the Assay.
Alcohol content (if present)á611ñ: between 6.0%and 8.0%of C2H5OH.
Assay— Transfer 10mLof Oral Solution,accurately measured,to a separator.Transfer about 40mg of USP Chlorpheniramine Maleate RS,accurately weighed,to a 100-mLvolumetric flask,dilute with water to volume,mix,and pipet 10mLof this Standard solution into a separator similar to that containing the Oral Solution.Treat each solution as follows.Add 10mLof sodium hydroxide solution (1in 10),and extract with two 50-mLportions of solvent hexane.Combine the extracts in a second separator,wash with 10mLof sodium hydroxide solution (1in 250),and discard the washing.Extract the hexane solution with two 40-mLportions of dilute hydrochloric acid (1in 100),collect the extracts in a 100-mLvolumetric flask,add the same dilute acid to volume,and mix.Wash 50-mLportions of each solution,and of dilute hydrochloric acid (1in 100),respectively,with three 30-mLportions of chloroform and then with 50mLof solvent hexane,and discard the washings.Filter the acid phases through paper,discarding the first few mLof each filtrate,and determine the absorbances of the solutions obtained from the Oral Solution and the Standard solution in 1-cm cells at the wavelength of maximum absorbance at about 264nm,with a suitable spectrophotometer,using the extracted acid as the blank.Calculate the quantity,in µg,of chlorpheniramine maleate (C16H19ClN2·C4H4O4)in each mLof the Oral Solution taken by the formula:
C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Chlorpheniramine Maleate RSin the Standard solution;and AUand ASare the absorbances of the solutions from the Oral Solution and the Standard solution,respectively.
(Official June 1,2005)
Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 450
Pharmacopeial Forum:Volume No.28(2)Page 263
Phone Number:1-301-816-8379