A: The chromatogram of the Assayobtained as directed in the Assayexhibits a major peak for ceftazidime,the retention time of which corresponds to that in the chromatogram of the Standard preparation,as obtained in the Assay.

B: It dissolves in 1Nhydrochloric acid with effervescence,evolving a colorless gas,which when passed into calcium hydroxide TSproduces a white precipitate immediately.

Potassium chloride solution— Dissolve 19.07g of potassium chloride in water to make 1000mLof solution.

Standard preparation— Dissolve a suitable quantity of sodium chloride,previously dried at 105for 2hours and accurately weighed,in water to obtain a solution having a known concentration of about 14µg per mL.Transfer 10mLof this solution to a 100-mLvolumetric flask,add 10.0mLof Potassium chloride solution,dilute with water to volume,and mix.

Test preparation— Use the stock solution used to prepare Assay preparation 1in the Assay,diluting it quantitatively,and stepwise if necessary,with water to obtain a solution containing about 12.5µg of sodium carbonate per mL.Transfer 10.0mLof this solution to a 100-mLvolumetric flask,add 10.0mLof Potassium chloride solution,dilute with water to volume,and mix.

Blank solution— Transfer 10.0mLof Potassium chloride solutionto a 100-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Concomitantly determine the absorbances of the Standard preparationand the Test preparationat the sodium emission line of 589.0nm,with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-Scattering á851ñ)equipped with a sodium hollow-cathode lamp and an air–acetylene flame,using the Blank solutionas the blank.Calculate the percentage of sodium carbonate (Na2CO3)in the portion of Ceftazidime for Injection taken by the formula: in which 105.99is the molecular weight of sodium carbonate;116.88is twice the molecular weight of sodium chloride;Cis the concentration,in µg per mL,of sodium chloride in the Standard preparation;Mis the quantity,in mg,of Ceftazidime for Injection in each mLof the Test preparation,based on the quantity taken to prepare the stock solution and the extent of dilution;and AUand ASare the absorbances of the Test preparationand the Standard preparation,respectively.Use this percentage to calculate,on the dried and sodium carbonate-free basis,the result from Assay preparation 1obtained as directed in the Assay.

Mobile phase— Mix 300mLof acetonitrile and 100mLof 0.25Mmonobasic ammonium phosphate,dilute with water to obtain 1000mLof solution,and adjust with ammonium hydroxide to a pHof 7.0±0.1.Pass this solution through a filter having a 1-µm or finer porosity,and degas.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

pH7buffer— Dissolve 5.68g of anhydrous dibasic sodium phosphate and 3.63g of monobasic potassium phosphate in water to make 1000mLof solution.

Standard solution— Transfer about 250mg of pyridine,accurately weighed,to a 100-mLvolumetric flask,dilute with water to volume,and mix.Immediately prior to chromatography,transfer 2.0mLof this solution to a 200-mLvolumetric flask,dilute with pH7bufferto volume,and mix.This solution contains about 25µg of pyridine per mL.

Test solution— Transfer about 660mg of Ceftazidime for Injection,just removed from its container and accurately weighed,to a 100-mLvolumetric flask,promptly add 50mLof pH7bufferto volume,and mix.Store this solution in a cool place,and use it within 1hour.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 254-nm detector and a 4.6-mm ×25-cm column that contains 5-µm packing L1.The flow rate is about 1.6mLper minute.Chromatograph the Standard solution,and record the peak responses as directed for Procedure:the tailing factor for the analyte peak is not more than 2.5;and the relative standard deviation for replicate injections is not more than 3%.

Procedure— Separately inject equal volumes (about 10µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the areas of the responses for the pyridine peaks.Calculate the percentage of pyridine in the portion of Ceftazidime for Injection taken by the formula: in which Cis the concentration,in µg per mL,of pyridine in the Standard solution;Wis the weight,in mg,of Ceftazidime for Injection taken;and rUand rSare the pyridine peak responses obtained from the Test solutionand the Standard solution,respectively:not more than 0.4%of pyridine is found where it contains sodium carbonate;and not more than 0.3%where it contains arginine.

Mobile phase— Dissolve 1.15g of monobasic ammonium phosphate in about 800mLof water.Adjust with phosphoric acid to a pHof 2.0±0.1,dilute with water to 1000mL,and mix.Prepare a filtered and degassed mixture of acetonitrile and this solution (750:250).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Dissolve accurately weighed quantities of USP Ceftazidime Pentahydrate RSand USPL-Arginine RSin water to obtain a solution containing known concentrations of about 0.2mg of each per mL.

Test preparation— Quantitatively dissolve an accurately weighed portion of Ceftazidime for Injection in water to obtain a solution having a concentration of about 0.2mg of ceftazidime per mL.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 206-nm detector,a 4.6-mm ×50-cm saturator pre-column containing packing L27,and a 4-mm ×25-cm analytical column containing packing L20.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the responses as directed for Procedure:the resolution,R,between the ceftazidime and the arginine peaks is not less than 6.0;and the tailing factor for the arginine peak is not more than 4.0.

Procedure— Separately inject equal volumes (about 20µLof the Standard preparationand the Test preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the percentage of arginine (C6H14N4O2)in the Ceftazidime for Injection taken by the formula: in which CSis the concentration,in mg per mL,of USPL-Arginine RSin the Standard preparation;CUis the concentration,in mg per mL,of Ceftazidime for Injection in the Test preparation,based on the weight,in mg,of Ceftazidime for Injection taken and the extent of dilution;and rUand rSare the arginine peak responses obtained from the Test preparationand the Standard preparation,respectively.Use this percentage to calculate,on the anhydrous and arginine-free basis,the assay result from Assay preparation 1obtained as directed in the Assay.

pH7buffer,Mobile phase,Standard preparation,Resolution solution,and Chromatographic system— Proceed as directed in the Assayunder Ceftazidime.

Assay preparation 1— Transfer an accurately weighed quantity of Ceftazidime for Injection,equivalent to about 250mg of ceftazidime (C22H22N6O7S2),to a 250-mLvolumetric flask,dilute with water to volume,and mix to obtain a stock solution.[NOTE—Protect this solution from light.]Immediately prior to chromatography,transfer 5.0mLof this solution to a 50-mLvolumetric flask,dilute with water to volume,and mix.

Assay preparation 2 (where it is represented as being in a single-dose container)—Constitute a container of Ceftazidime for Injection in a volume of water,accurately measured,corresponding to the volume of solvent specified in the labeling.Withdraw all of the withdrawable contents,using a suitable hypodermic needle and syringe,and dilute quantitatively with water to obtain a solution containing about 1mg of ceftazidime (C22H22N6O7S2)per mL.[NOTE—Protect this solution from light.]Immediately prior to chromatography,transfer 5.0mLof this solution to a 50-mLvolumetric flask,dilute with water to volume,and mix.

Assay preparation 3 (where the label states the quantity of ceftazidime in a given volume of constituted solution)—Constitute a container of Ceftazidime for Injection in a volume of water,accurately measured,corresponding to the volume of solvent specified in the labeling.Dilute an accurately measured volume of the constituted solution quantitatively with water to obtain a solution containing about 1mg of ceftazidime (C22H22N6O7S2)per mL.[NOTE—Protect this solution from light.]Immediately prior to chromatography,transfer 5.0mLof this solution to a 50-mLvolumetric flask,dilute with water to volume,and mix.

Procedure— Proceed as directed for Procedurein the Assayunder Ceftazidime.Calculate the percentage of ceftazidime (C22H22N6O7S2)on the dried and sodium carbonate-free or arginine-free basis in the portion of Ceftazidime for Injection taken by the formula: in which Cis the concentration,in µg per mL,of ceftazidime (C22H22N6O7S2)in the Standard preparation;Wis the quantity,in mg,of Ceftazidime for Injection taken to prepare Assay preparation 1;mis the total percentage of loss on drying;sis the percentage of sodium carbonate or arginine in the Ceftazidime for Injection taken;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.Calculate the quantity,in mg,of ceftazidime (C22H22N6O7S2)withdrawn from the container,or in the portion of constituted solution taken by the formula: in which Lis the labeled quantity,in mg,of ceftazidime (C22H22N6O7S2)in the container,or in the volume of constituted solution taken;and Dis the concentration,in µg of ceftazidime (C22H22N6O7S2)per mL,of Assay preparation 2or Assay preparation 3,based on the labeled quantity in the container or in the portion of constituted solution taken,respectively,and the extent of dilution.