Potassium Chloride Oral Solution, chemical structure, molecular formula, Reference Standards

Potassium Chloride Oral Solution

»Potassium Chloride Oral Solution contains not less than 95.0percent and not more than 105.0percent of the labeled amount of KCl.It may contain alcohol.

Packaging and storage— Preserve in tight containers.

Identification— Carefully evaporate about 5mLto dryness,and ignite the residue at dull-red heat to remove all organic matter.Cool,dissolve the residue in 10mLof water,and filter:the filtrate responds to the tests for Potassium á191ñand for Chloride á191ñ.

Alcohol content (if present)á611ñ: not less than 90.0%and not more than 115.0%of the labeled amount,the labeled amount being not more than 7.5%of C2H5OH,determined by the gas-liquid chromatographic procedure,acetone being used as the internal standard.

Assay—

Potassium stock solution— Dissolve 190.7mg of potassium chloride,previously dried at 105

for 2hours,in water.Transfer to a 1000-mLvolumetric flask,dilute with water to volume,and mix.Transfer 100.0mLof this solution to a 1000-mLvolumetric flask,dilute with water to volume,and mix.This solution contains 10µg of potassium (equivalent to 19.07µg of potassium chloride)per mL.

Standard preparations— To separate 100-mLvolumetric flasks transfer 10.0,15.0,and 20.0mL,respectively,of Potassium stock solution.To each flask add 2.0mLof sodium chloride solution (1in 5)and 1.0mLof hydrochloric acid,dilute with water to volume,and mix.The Standard preparationscontain,respectively,1.0,1.5,and 2.0µg of potassium per mL.

Assay preparation— Transfer an accurately measured volume of Oral Solution,equivalent to about 600mg of potassium chloride,to a 500-mLvolumetric flask,dilute with water to volume,and mix.Transfer 5.0mLof the solution to a 100-mLvolumetric flask,dilute with water to volume,and mix.Transfer 5.0mLof the resulting solution to a 100-mLvolumetric flask,add 2.0mLof sodium chloride solution (1in 5)and 1.0mLof hydrochloric acid,dilute with water to volume,and mix.

Procedure— Concomitantly determine the absorbances of the Standard preparationsand the Assay preparationat the potassium emission line of 766.5nm,with a suitable atomic absorption spectrophotometer (see Spectrophotometry and Light-scattering á851ñ)equipped with a potassium hollow-cathode lamp and an air–acetylene flame,using water as the blank.Plot the absorbance of the Standard preparationversus concentration,in µg per mL,of potassium,and draw the straight line best fitting the three plotted points.From the graph so obtained,determine the concentration,in µg per mL,of potassium in the Assay preparation.Calculate the quantity,in mg,of KCl in the portion of Oral Solution taken by the formula:

200C(1.907),

in which Cis the concentration,in µg per mL,of potassium in the Assay preparation,and 1.907is the ratio of the molecular weight of potassium chloride to the atomic weight of potassium.

Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist

Expert Committee:(PA1)Pharmaceutical Analysis 1

USP28–NF23Page 1585

Phone Number:1-301-816-8379