Identification—
A:
The retention time of the major peak in the chromatogram of the
Assay preparationcorresponds to that in the chromatogram of the
Standard preparation,as obtained in the
Assay.
B:
Thin-Layer Chromatographic Identification Test á201ñ—
Test solution—
Dissolve Indomethacin for Injection in methanol to obtain a solution having a concentration of about 5mg of indomethacin per mL.
Standard solution:
5mg per mLin methanol.
Developing solvent system:
a mixture of chloroform and glacial acetic acid (19:1).
Procedure—
Proceed as directed in the chapter,except to dry the spots with the aid of a current of air.The intensity and RFvalue of the principal spot obtained from the Test solutioncorrespond to those obtained from the Standard solution.
Bacterial endotoxins—
Using a test solution,prepared by dissolving Indomethacin for Injection in LAL Reagent Water to obtain a concentration of 1.0mg of indomethacin per mL,proceed as directed under
Bacterial Endotoxins Test á85ñ.It contains not more than 20.0USP Endotoxin Units per mg of indomethacin.
Limit of 4-chlorobenzoic acid—
Mobile phase
and
Solvent mixture—Prepare as directed in the
Assay.
Standard preparation—
Dissolve a suitable quantity of 4-chlorobenzoic acid,accurately weighed,in acetonitrile to obtain a solution having a known concentration of about 0.22mg per mL.Transfer 1.0mLof this solution to a 500-mLvolumetric flask,add 150mLof acetonitrile,dilute with water to volume,and mix.This solution contains about 0.44µg of 4-chlorobenzoic acid per mL.
Test preparation—
Use the Assay preparation.
Chromatographic system—
Prepare as directed in the
Assay.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the capacity factor,
k¢,for the 4-chlorobenzoic acid peak is not less than 1.0.
Procedure—
Separately inject equal volumes (about 50µL)of the
Standard preparationand the
Test preparationinto the chromatograph,record the chromatograms,and measure the 4-chlorobenzoic acid peak areas.Calculate the percentage of 4-chlorobenzoic acid in the portion of Indomethacin for Injection taken by the formula:
10(C4/NCA)(rU/rS),
in which
C4is the concentration,in µg per mL,of 4-chlorobenzoic acid in the
Standard preparation;Nis the number of containers of Indomethacin for Injection taken;
CAis the quantity,in mg,of indomethacin (C
19H
16ClNO
4)in each container of Indomethacin for Injection taken,determined as directed herein;and
rUand
rSare the 4-chlorobenzoic acid peak areas obtained from the
Test preparationand the
Standard preparation,respectively:not more than 2.2%,equivalent to not more than 5.0%,calculated as indomethacin,is found.
Assay—
Mobile phase—
Prepare a suitable mixture of methanol,water,and phosphoric acid (600:400:1),and pass through a suitable filter having a 0.5-µm or finer porosity.Make adjustments if necessary (see
System Suitabilityunder
Chromatography á621ñ).
Solvent mixture—
Prepare a mixture of water,acetonitrile,and phosphoric acid (700:300:1).
Standard preparation—
Transfer about 20mg of
USP Indomethacin RS,accurately weighed,to a 200-mLvolumetric flask,and dissolve in 60mLof acetonitrile.Dilute with water to volume,and mix.
Assay preparation—
Select an accurately counted number of containers of Indomethacin for Injection,equivalent to a total of about 10mg of indomethacin,and constitute each with a volume of Solvent mixturesufficient to obtain solutions containing the equivalent of about 0.5mg of indomethacin per mL.Wash the contents of these containers with the aid of the Solvent mixtureinto a 100-mLvolumetric flask.Dilute with Solvent mixtureto volume,mix,and pass through a filter having a 0.5-µm or finer porosity.Use the filtrate as the Assay preparation.
Chromatographic system
(see
Chromatography á621ñ)—The liquid chromatograph is equipped with a 240-nm detector and a 3.9-mm ×30-cm column that contains packing L1.The flow rate is about 2mLper minute.Chromatograph the
Standard preparation,and record the peak responses as directed for
Procedure:the column efficiency determined from the indomethacin peak is not less than 1500theoretical plates;the capacity factor,
k¢,for the indomethacin peak is not less than 3.5;the tailing factor for the indomethacin peak is not more than 2.0;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 50µL)of the
Standard preparationand the
Assay preparationinto the chromatograph,record the chromatograms,and measure the areas for the major peaks.Calculate the quantity,
CA,in mg,of indomethacin (C
19H
16ClNO
4)in each container of Indomethacin for Injection taken by the formula:
100(C/N)(rU/rS),
in which
Cis the concentration,in mg per mL,of
USP Indomethacin RSin the
Standard preparation;Nis the number of containers of Indomethacin for Injection taken;and
rUand
rSare the indomethacin peak responses obtained from the
Assay preparationand the
Standard preparation,respectively.