Solution— Dilute a quantity of Suspension with a mixture of methanol and hydrochloric acid (99:1)to obtain a solution having a concentration of about 1mg per mL.Filter the mixture,if necessary,to obtain a clear solution.Transfer 1mLof this solution to a 100-mLvolumetric flask,dilute with 0.1Nsodium hydroxide to volume,and mix.

Acidified methanol— Use a mixture of methanol and hydrochloric acid (99:1).

Mobile phase— Dissolve 11.0g of monobasic sodium phosphate in 800mLof water.Add 1200mLof methanol,and mix.Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).

Standard preparation— Quantitatively dissolve an accurately weighed quantity of USP Albendazole RSin Acidified methanolto obtain a stock solution having a known concentration of about 1mg per mL.Dilute an accurately measured volume of this stock solution with Mobile phaseto obtain a solution having a known concentration of about 100µg per mL.

Assay preparation— Transfer an accurately measured volume of Oral Suspension,equivalent to about 100mg of albendazole,to a 100-mLvolumetric flask,dilute with Acidified methanolto volume,and mix.Transfer 10.0mLof this solution to a second 100-mLvolumetric flask,dilute with Mobile phaseto volume,and mix.Filter,if necessary,to obtain a clear solution.

Chromatographic system(see Chromatography á621ñ)— The liquid chromatograph is equipped with a 308-nm detector and a 4-mm ×25-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 is not less than 2000theoretical plates;the tailing factor 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 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 albendazole (C12H15N3O2S)in each mLof the Oral Suspension taken by the formula: in which Cis the concentration,in µg per mL,of USP Albendazole RSin the Standard preparation;and rUand rSare the albendazole peak responses obtained from the Assay preparationand the Standard preparation,respectively.