Indomethacin
;)
1H-Indole-3-acetic acid,1-(4-chlorobenzoyl)-5-methoxy-2-methyl-.
1-(p-Chlorobenzoyl)-5-methoxy-2-methylindole-3-acetic acid [53-86-1].
»Indomethacin contains not less than 98.0percent and not more than 101.0percent of C19H16ClNO4,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed,light-resistant containers.
Identification—
A:
Infrared Absorption á197Mñ.
B:
Ultraviolet Absorption á197Uñ—
Solution:
25µg per mL.
Medium:
hydrochloric acid in methanol (1in 120).
Absorptivities at 318nm,calculated on the dried basis,do not differ by more than 3.0%.
C:
Its X-ray diffraction pattern (see X-ray Diffraction á941ñ)conforms to that of USP Indomethacin RS.
Loss on drying á731ñ—
Dry it at a pressure below 5mm of mercury at 100
for 2hours:it loses not more than 0.5%of its weight.
for 2hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.2%.
Heavy metals,Method IIá231ñ:
0.002%.
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Assay—
Mobile phase—
Prepare a suitable solution of 0.01Mmonobasic sodium phosphate and 0.01Mdibasic sodium phosphate in acetonitrile and water (approximately 1:1).
Standard preparation—
Dissolve an accurately weighed quantity of USP Indomethacin RSin Mobile phaseto obtain a solution having a known concentration of about 0.1mg per mL.
Assay preparation—
Weigh accurately about 100mg of Indomethacin,and transfer to a 100-mLvolumetric flask.Dissolve in and dilute with Mobile phaseto volume,and mix.Pipet 10mLof this solution into a 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.
Chromatographic system
(see Chromatography á621ñ)—The liquid chromatograph is equipped with a 254-nm detector and a 4-mm ×30-cm column that contains 10-µm packing L1.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed under Procedure:the column efficiency determined from the analyte peak is not less than 500theoretical plates,and the relative standard deviation for replicate injections is not more than 1.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in mg,of C19H16ClNO4in the portion of Indomethacin taken by the formula:
1000C(rU/rS),
in which Cis the concentration,in mg per mL,of USP Indomethacin RSin the Standard preparation,and rUand rSare the peak responses obtained at equivalent retention times from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:Clydewyn M.Anthony,Ph.D.,Scientist
Expert Committee:(PA2)Pharmaceutical Analysis 2
USP28–NF23Page 1013
Phone Number:1-301-816-8139