C S= concentration of USP Azithromycin RS in the Sample solution: Nominally 1mg/mL of azithromycinStandard solution (mg/mL)in Mobile phase from NLT 20 Tablets, finely powdered.C U= nominal concentration of azithromycin in Sonicate and shake as needed to dissolve.Sample solution 1 (mg/mL)Chromatographic systemP= potency of azithromycin in USP Azithromycin(See Chromatography 〈621〉, System Suitability.) RS (µg/mg)Mode: LCF= conversion factor, 0.001mg/µg Detector: UV 210 nmWhere packaged in a multiple-unit container Column: 4.6-mm × 25-cm; 5-µm packing L1Calculate the percentage of the labeled amount of Column temperature: 50°azithromycin (C38H72N2O12) in the portion of Flow rate: 2mL/minAzithromycin for Oral Suspension taken:Injection volume: 100µLSystem suitabilityResult = (r U/r S) × (C S/C U) ×P×F× 100Sample:Standard solutionSuitability requirementsr U= peak response from Sample solution 2Tailing factor: NMT 2.0, Standard solutionr S= peak response from the Standard solution Relative standard deviation: NMT 2.0%, StandardC S= concentration of USP Azithromycin RS in the solutionStandard solution (mg/mL)AnalysisC U= nominal concentration of azithromycin in Samples:Standard solution and Sample solutionSample solution 2 (mg/mL)Calculate the percentage of the labeled amount of P= potency of azithromycin in USP Azithromycin azithromycin (C38H72N2O12) in the portion of Tablets RS (µg/mg)taken:F= conversion factor, 0.001mg/µgAcceptance criteria: 90.0%–110.0%Result = (r U/r S) × (C S/C U) ×P×F× 100PERFORMANCE TESTS rU= peak response of azithromycin from the•D ELIVERABLE V OLUME〈698〉: Meets the requirements Sample solution•U NIFORMITY OF D OSAGE U NITS〈905〉rS= peak response of azithromycin from the For single-unit containers Standard solutionAcceptance criteria: Meets the requirements CS= concentration of USP Azithromycin RS in theStandard solution (mg/mL)SPECIFIC TESTS CU= nominal concentration of azithromycin in the •P H 〈791〉Sample solution (mg/mL) For a solid packaged in single-unit containers:P= potency of USP Azithromycin RS (µg/mg)9.0–11.0, in the suspension constituted as directed in F= conversion factor, 0.001mg/µgthe labeling Acceptance criteria: 90.0%–110.0%For a solid packaged in multiple-unit containers:8.5–11.0, in the suspension constituted as directed in PERFORMANCE TESTSthe labeling•D ISSOLUTION〈711〉Medium: pH 6.0phosphate buffer; 900mL ADDITIONAL REQUIREMENTS Apparatus 2: 75 rpm•P ACKAGING AND S TORAGE: Preserve in tight containers.Time: 30 min•USP R EFERENCE S TANDARDS〈11〉Solution A: 4.4mg/mL of dibasic potassium phosphate USP Azaerythromycin A RS and 0.5mg/mL of sodium 1-octanesulfonate, adjusted 9-Deoxo-9a-aza-9a-homoerythromycin A;with phosphoric acid to a pH of 8.20 ± 0.056-Demethylazithromycin.Mobile phase: Acetonitrile, methanol, and Solution A C37H70N2O12734.96(9:3:8)USP Azithromycin RS Diluent: 17.5mg/mL of dibasic potassium phosphate.Adjust with phosphoric acid to a pH of 8.00 ± 0.05.Prepare a mixture of this solution and acetonitrile(80:20).Standard stock solution: Dissolve USP Azithromycin RS Azithromycin Tablets in Medium to obtain a solution having a known concen-tration of about (L/1000) mg/mL, where L is the Tablet DEFINITION label claim in mg.Azithromycin Tablets contain NLT 90.0% and NMT 110.0%Standard solution: Dilute the Standard stock solutionof the labeled amount of azithromycin (C38H72N2O12).with Diluent to obtain a solution having a known con-centration of about (L/2000) mg/mL, where L is the IDENTIFICATION Tablet label claim in mg.•A. The retention time of the major peak of the Sample Sample solution: Pass a portion of the solution under solution corresponds to that of the Standard solution, as test through a suitable filter of 0.45-µm pore size. Di-obtained in the Assay.lute a portion of the filtrate with Diluent to obtain asolution having a theoretical concentration of about ASSAY(L/2000) mg/mL, where L is the Tablet label claim in•P ROCEDURE mg, assuming complete dissolution.Buffer: Dissolve 4.6g of monobasic potassium phos-Chromatographic systemphate anhydrous in 900mL of water. Adjust with 1N(See Chromatography 〈621〉, System Suitability.)sodium hydroxide to a pH of 7.5, and dilute with waterto 1L.Mobile phase: Acetonitrile and Buffer (65:35)Standard solution: 1mg/mL of USP Azithromycin RS inMobile phase. Sonicate and shake as needed to dissolve.Mode: LC Standard stock solution: 0.4mg/mL of USP Azithro-Detector: UV 210 nm mycin RS in acetonitrile. Sonicate and shake as needed Column: 4.6-mm × 15-cm; 5-µm packing L1to dissolve.Column temperature: 50°Standard solution: 0.02mg/mL of azithromycin from Flow rate: 1.5mL/min Standard stock solution in Diluent AInjection volume: 50µL Sensitivity solution: 0.004mg/mL of azithromycin System suitability from Standard solution in Diluent ASample:Standard solution Sample stock solution: Nominally 14.3mg/mL of Suitability requirements azithromycin prepared as follows. Weigh and finely Tailing factor: NMT 2.0powder NLT 20 Tablets. Transfer nominally 1430mg of Relative standard deviation: NMT 2.0%azithromycin to a 100-mL volumetric flask. Add 75mL Analysis of acetonitrile, and sonicate for NLT 15 min. Shake by Samples:Standard solution and Sample solution mechanical means for NLT 15 min. Allow the solution Calculate the percentage of the labeled amount of to equilibrate to room temperature, dilute with acetoni-azithromycin (C38H72N2O12) dissolved:trile to volume, and mix.Sample solution: Nominally 4mg/mL of azithromycin Result = (r U/r S) × (C S/L) ×V× 100prepared as follows. Centrifuge an aliquot of the Samplestock solution for NLT 15 min. Transfer 7.0mL of the r U= peak response of azithromycin from the supernatant to a 25-mL volumetric flask, and dilute Sample solution with Diluent B to volume.r S= peak response of azithromycin from the Blank:Diluent AStandard solution Chromatographic systemC S= concentration of the Standard solution(See Chromatography 〈621〉, System Suitability.)(mg/mL)Mode: LCL= label claim (mg/Tablet)Detector: UV 210 nmV= volume of Medium, 900mL Column: 4.6-mm × 15-cm; 3.5-µm packing L1 Tolerances: NLT 80% (Q) of the labeled amount of Column temperature: 50°azithromycin (C38H72N2O12) is dissolved.Flow rate: 1.2mL/min•U NIFORMITY OF D OSAGE U NITS〈905〉: Meet the Autosampler temperature: 4°requirements Injection volume: 100µLSystem suitabilityIMPURITIES Samples:System suitability solution, Standard solution,•O RGANIC I MPURITIES and Sensitivity solutionProtect all solutions containing azithromycin from light.Suitability requirementsRefrigerate the Standard solution and the Sample solution Signal-to-noise ratio: NLT 10, Sensitivity solution after preparation and during analysis, using a refriger-Resolution: NLT 1.0 between desosaminylazithromy-ated autosampler set at 4°. The solutions must be ana-cin and azithromycin related compound F, System lyzed within 24 h of preparation.suitability solutionSolution A: Water and ammonium hydroxide Relative standard deviation: NMT 2.0%, Standard (2000:1.2). The pH of this solution is about 10.5.solutionSolution B: Acetonitrile, methanol, and ammonium hy-Analysisdroxide (1800:200:1.2)Samples:Sample solution and BlankMobile phase: See Table 1.Calculate the percentage of each impurity in the por-tion of Tablets taken:Table 1Result = (r U/r S) × (C S/C U) ×P×F1× (1/F2) × 100 Time Solution A Solution B(min)(%)(%)rU= peak response of each impurity from the 05446Sample solution205446r S= peak response of azithromycin from theStandard solution351090C S= concentration of USP Azithromycin RS in the35.15446Standard solution (mg/mL) 405446CU= nominal concentration of azithromycin in theSample solution (mg/mL) Buffer: 1.7g/L of monobasic ammonium phosphate inP= potency of USP Azithromycin RS (µg/mg) water. Adjust with ammonium hydroxide to a pH of 10.F1= conversion factor, 0.001mg/µg Diluent A: Methanol, acetonitrile, and BufferF2= relative response factor (see Table 2) (350:300:350)Acceptance criteria: See Table 2. The reporting level Diluent B: Methanol and Buffer (1:1)for impurities is 0.1%. Disregard any peaks in the Sam-System suitability stock solution: 0.1mg/mL each ofple solution that correspond to peaks in the Blank.USP Desosaminylazithromycin RS and USP AzithromycinRelated Compound F RS in acetonitrileSystem suitability solution: 0.028mg/mL each of USPDesosaminylazithromycin RS and USP Azithromycin Re-lated Compound F RS from System suitability stock solu-tion in Diluent ATable 2Table 2 (Continued)Relative Relative Acceptance Relative Relative AcceptanceRetention Response Criteria,Retention Response Criteria, Name Time Factor NMT (%)Name Time Factor NMT (%) Azithromycin N-ox-3-Deoxyazithro-ide a0.200.42 1.0mycin (azithro-——mycin B)h,l 1.143′-(N,N-Didemeth-yl)-3′-N-for-Any individual un-—mylazithromycin b0.29 1.7 1.0specified impurity h 1.00.23′-(N,N-Didemeth-Total impurities h—— 5.0yl)azithro-a(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10, mycin(ami-12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylazinoyl)-β-D-xylo-hex-noazithromycin)c0.340.490.5opyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.Azithromycin related b(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-compound F d0.42 4.3 1.0methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3-formamido-3,4,6-trideoxy-β-D-xylo-hexopyra-Desosaminylazithro-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.mycin e0.46 1.10.5c(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-N-Demethylazithro-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3-amino-3,4,6-trideoxy-β-D-xylo-hexopyra-mycin f0.500.540.7nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.3′-De(dimethylami-d3′-(N-Demethyl)-3′-N-formylazithromycin; (2R,3S,4R,5R,8R,10R,11R,12S, no)-3′-oxoazithro-13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyra-mycin g0.87 1.4 1.0nosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3-(N-methyl)formamido-3,4,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-Azaerythromycin A h,i0.94——azacyclopentadecan-15-one.Azithromycin 1.0——e(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-Ethyl-3,4,10,13-tetrahydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-D-xylo-2-Desethyl-2-prop-——hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. ylazithromycin h,j 1.10f(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-3′-N-Demethyl-3′-N-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,[(4-methylphen-12,14-heptamethyl-11-[[3,4,6-trideoxy-3-methylamino-β-D-xylo-hexopyra-——nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.yl)sulfonyl]azithro-g(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3,3-dimethyl-α-mycin h,k 1.11L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-a(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-heptamethyl-11-[[3,4,6-trideoxy-3-oxo-β-D-xylo-hexopyranosyl]oxy]-1-oxa-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,6-azacyclopentadecan-15-one.12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylazinoyl)-β-D-xylo-hex-h Process impurities that are controlled in the drug substance are not to be opyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.reported. They are listed here for information only. The unspecified impu-b(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-rities and total impurities limits do not include these impurities.methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,i9-Deoxo-9a-aza-9a-homoerythromycin A.12,14-heptamethyl-11-[[3-formamido-3,4,6-trideoxy-β-D-xylo-hexopyra-j(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.methyl-α-L-ribo-hexopyranosyl)oxy]-2-propyl-3,4,10-trihydroxy-3,5,6,8,10, c(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hex-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,opyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one dihydrate.12,14-heptamethyl-11-[[3-amino-3,4,6-trideoxy-β-D-xylo-hexopyra-k(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10, d3′-(N-Demethyl)-3′-N-formylazithromycin; (2R,3S,4R,5R,8R,10R,11R,12S,12,14-heptamethyl-11-[[3-[N-(4-methylphenylsulfonyl)-N-methylamino]-3, 13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyra-4,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-nosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3-one.(N-methyl)formamido-3,4,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-l(2R,3R,4S,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-azacyclopentadecan-15-one.methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-4,10-dihydroxy-3,5,6,8,10,12, e(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-Ethyl-3,4,10,13-tetrahydroxy-3,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyra-5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-D-xylo-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.f(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-ADDITIONAL REQUIREMENTSmethyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,•PACKAGING AND S TORAGE: Preserve in tight containers. 12,14-heptamethyl-11-[[3,4,6-trideoxy-3-methylamino-β-D-xylo-hexopyra-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.Store at controlled room temperature.g(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3,3-dimethyl-α-•USP R EFERENCE S TANDARDS〈11〉L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14-USP Azithromycin RSheptamethyl-11-[[3,4,6-trideoxy-3-oxo-β-D-xylo-hexopyranosyl]oxy]-1-oxa-USP Azithromycin Related Compound F RS6-azacyclopentadecan-15-one.3′-(N-Demethyl)-3′-N-formylazithromycin;h Process impurities that are controlled in the drug substance are not to be(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dide-reported. They are listed here for information only. The unspecified impu-rities and total impurities limits do not include these impurities.oxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyra-i9-Deoxo-9a-aza-9a-homoerythromycin A.nosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,j(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-14-heptamethyl-11-[[3-(N-methyl)formamido-3,4, methyl-α-L-ribo-hexopyranosyl)oxy]-2-propyl-3,4,10-trihydroxy-3,5,6,8,10,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-aza-12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hex-cyclopentadecan-15-one.opyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one dihydrate.C38H70N2O13762.97k(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10, USP Desosaminylazithromycin RS12,14-heptamethyl-11-[[3-[N-(4-methylphenylsulfonyl)-N-methylamino]-3,(2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-Ethyl-3,4,4,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-10,13-tetrahydroxy-3,5,6,8,10,12,14-heptamethyl-11 one.-[[3,4,6-trideoxy-3-dimethylamino-β-D-xylo-hexopyra-l(2R,3R,4S,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O-nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-4,10-dihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyra-C30H58N2O9590.79nosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one.Suitability requirementsResolution: NLT 2.0 between aztreonam and aztre-Aztreonamonam E -isomer, System suitability solutionTailing factor: NMT 2 for aztreonam, System suitabil-ity solutionRelative standard deviation: NMT 2.0%, Standard solution AnalysisSamples: Standard solution and Sample solutionCalculate the percentage of aztreonam (C 13H 17N 5O 8S 2)in the portion of Aztreonam taken:Result = (r U /r S ) × (C S /C U ) × P × F × 100C 13H 17N 5O 8S 2435.43r U = peak response from the Sample solution Propanoic acid, 2-[[[1-(2-amino-4-thiazolyl)-2-[(2-methyl-r S = peak response from the Standard solution 4-oxo-1-sulfo-3-azetidinyl)amino]-2-oxoethylidene]ami-C S= concentration of USP Aztreonam RS in theno]oxy]-2-methyl-, [2S -[2α,3β(Z )]]-;Standard solution (mg/mL)(Z )-2-[[[(2-Amino-4-thiazolyl)[[(2S ,3S )-2-methyl-4-oxo-C U = concentration of Aztreonam in the Sample1-sulfo-3-azetidinyl]carbamoyl]methylene]amino]oxy]-solution (mg/mL)2-methylpropionic acid [78110-38-0].P = potency of USP Aztreonam RS (µg/mg)F = unit conversion factor, 0.001mg/µgDEFINITIONAcceptance criteria: 92.0%–105.0% on the anhydrous Aztreonam, which may be anhydrous or hydrated, contains and solvent-free basisNLT 92.0% and NMT 105.0% of C 13H 17N 5O 8S 2, calculated on the anhydrous and solvent-free basis.IMPURITIESInorganic ImpuritiesIDENTIFICATION•R ESIDUE ON I GNITION 〈281〉: NMT 0.1%, the charred resi-•I NFRARED A BSORPTION 〈197K 〉: If a difference appears in due being moistened with 2mL of nitric acid and the IR spectra of the analyte and the standard, dissolve 5drops of sulfuric acidequal portions of the test specimen and the reference standard in equal volumes of methanol. [N OTE —To achieve a complete dissolution, it is suggested to use Delete the following:about 25mL of methanol for each 50mg of material,and stir the mixture for 40 min at room temperature.]••H EAVY M ETALS , Method II 〈231〉: NMT 30ppm •(Official 1-Evaporate the solutions to dryness under vacuum, and Jan-2018)dry at 40° for 4 h under vacuum. Perform the test on Organic Impurities the residues.•P ROCEDURE[N OTE —Store the System suitability solution , Standard so-ASSAYlution , and Sample solution at 5°, and protect from light •P ROCEDUREto prevent isomerization of aztreonam Z -isomer to az-[N OTE —Store the System suitability solution , Standard so-treonam E -isomer.]lution , and Sample solution at 5°, and protect from light Mobile phase, System suitability solution, Standard to prevent isomerization of aztreonam Z -isomer to az-solution, Sample solution, Chromatographic system,treonam E -isomer.]and System suitability: Proceed as directed in the Buffer: 6.8mg/mL of monobasic potassium phosphate Assay .in water. Adjust with 1M phosphoric acid to a pH of Analysis3.0.Samples: Standard solution and Sample solutionMobile phase: Methanol and Buffer (1:4)Calculate the percentage of each impurity in the por-System suitability solution: 1mg/mL of USP Aztre-tion of Aztreonam taken:onam RS and 1mg/mL of USP Aztreonam E -Isomer RS in Mobile phaseResult = (r U /r S ) × (C S /C U ) × P × F × 100Standard solution: 1mg/mL of USP Aztreonam RS in Mobile phaser U= peak response of each impurity from theSample solution: 1mg/mL of Aztreonam in Mobile Sample solutionphaser S = peak response of aztreonam from the StandardChromatographic systemsolution(See Chromatography 〈621〉, System Suitability .)C S = concentration of USP Aztreonam RS in theMode: LCStandard solution (mg/mL)Detector: UV 254 nmC U = concentration of Aztreonam in the SampleColumn: 3.9-mm × 30-cm; 10-µm packing L1solution (mg/mL)Flow rate: 1.5mL/min P = potency of USP Aztreonam RS (µg/mg)Injection size: 10µL F = unit conversion factor, 0.001mg/µg System suitabilityAcceptance criteriaSamples: System suitability solution and Standard Individual impurities: See Table 1.solution[N OTE —The relative retention times for aztreonam and aztreonam E -isomer are 1.0 and 1.8, respectively.]。