Identification
A:
It meets the requirements of Identificationtest Aunder Trimethobenzamide Hydrochloride Capsules.
B:
Transfer a volume of Injection,equivalent to about 100mg of trimethobenzamide hydrochloride,to a separator containing 20mLof water.Add 2mLof 1Nsodium hydroxide,and proceed as directed in
Identificationtest
Bunder
Trimethobenzamide Hydrochloride Capsules,beginning with Extract with 15mLof chloroform.
C:
Dilute a portion of Injection quantitatively and stepwise with methanol to obtain a solution containing 2.5mg of trimethobenzamide hydrochloride per mL:this solution meets the requirements of the
Thin-layer Chromatographic Identification Test á201ñ,a solvent system consisting of a mixture of ethyl acetate,alcohol,and ammonium hydroxide (90:10:5)being used.
Assay
Transfer to a suitable separator an accurately measured volume of Injection,equivalent to about 200mg of trimethobenzamide hydrochloride.Add 5mLof water and 3mLof dilute hydrochloric acid (1in 12),and extract with four 20-mLportions of ether,collecting the ether extracts in a second separator,and transferring the aqueous layer to a 500-mLvolumetric flask.Wash the combined ether extracts with one 20-mLportion of water,transfer the aqueous layer to the 500-mLvolumetric flask,dilute with water to volume,and mix.Dilute 5.0mLof the solution with dilute hydrochloric acid (1in 120)to 100.0mL,and mix.Concomitantly determine the absorbances of this solution and a Standard solution of
USP Trimethobenzamide Hydrochloride RSin the same medium having a known concentration of about 20µg per mL,in 1-cm cells at the wavelength of maximum absorbance at about 258nm,with a suitable spectrophotometer,using dilute hydrochloric acid (1in 120)as the blank.Calculate the quantity,in mg,of C
21H
28N
2O
5·HCl in each mLof the Injection taken by the formula:
(10C/V)(AU/AS),
in which
Cis the concentration,in µg per mL,of USP Trimethobenzamide RSin the Standard solution,
Vis the volume,in mL,of Injection taken,and
AUand
ASare the absorbances of the solution from the Injection and the Standard solution,respectively.