Sodium Lactate Solution
»Sodium Lactate Solution is an aqueous solution containing not less than 50.0percent,by weight,of monosodium lactate.It contains not less than 98.0percent and not more than 102.0percent of the labeled amount of C3H5NaO3.
Packaging and storage— Preserve in tight containers.
Labeling— Label it to indicate its content of sodium lactate.
Identification— It responds to the tests for Sodium á191ñand for Lactate á191ñ.
pHá791ñ: between 5.0and 9.0.
Chloride á221ñ— Aportion,equivalent to 1g of sodium lactate,shows no more chloride than corresponds to 0.7mLof 0.020Nhydrochloric acid (0.05%).
Sulfate— To 10mLof a solution (1in 100)add 2drops of hydrochloric acid and 1mLof barium chloride TS:no turbidity is produced.
Heavy metals,Method Iá231ñ— Dilute a quantity of Solution,equivalent to 2.0g of sodium lactate,with 1Nacetic acid to 25mL:the limit is 0.001%.
Sugars— To 10mLof hot alkaline cupric tartrate TSadd 5drops of Solution:no red precipitate is formed.
Limit of citrate,oxalate,phosphate,or tartrate— Dilute 5mLwith recently boiled and cooled water to 50mL.To 4mLof this solution add 6Nammonium hydroxide or 3Nhydrochloric acid,if necessary,to bring the pHto between 7.3and 7.7.Add 1mLof calcium chloride TS,and heat in a boiling water bath for 5minutes:the solution remains clear.
Limit of methanol and methyl esters—
Potassium permanganateand phosphoric acid solution— Dissolve 3g of potassium permanganate in a mixture of 15mLof phosphoric acid and 70mLof water.Dilute with water to 100mL.
Oxalic acidand sulfuric acid solution— Cautiously add 50mLof sulfuric acid to 50mLof water,mix,cool,add 5g of oxalic acid,and mix to dissolve.
Standard preparation— Prepare a solution containing 10.0mg of methanol in 100mLof dilute alcohol (1in 10).
Test preparation— Place 40.0g in a glass-stoppered,round-bottom flask,add 10mLof water,and add cautiously 30mLof 5Npotassium hydroxide.Connect a condenser to the flask,and steam-distill,collecting the distillate in a suitable 100-mLgraduated vessel containing 10mLof alcohol.Continue the distillation until the volume in the receiver reaches approximately 95mL,and dilute the distillate with water to 100.0mL.
Procedure— Transfer 10.0mLeach of the Standard preparationand the Test preparationto 25-mLvolumetric flasks,to each add 5.0mLof Potassium permanganate and phosphoric acid solution,and mix.After 15minutes,to each add 2.0mLof Oxalic acid and sulfuric acid solution,stir with a glass rod until the solution is colorless,add 5.0mLof fuchsin-sulfurous acid TS,and dilute with water to volume.After 2hours,concomitantly determine the absorbances of both solutions in 1-cm cells at the wavelength of maximum absorbance at about 575nm,with a suitable spectrophotometer,using water as the blank:the absorbance of the solution from the Test preparationis not greater than that from the Standard preparation(0.025%).
Assay— Weigh accurately into a suitable flask a volume of Solution,equivalent to about 300mg of sodium lactate,add 60mLof a 1in 5mixture of acetic anhydride in glacial acetic acid,mix,and allow to stand for 20minutes.Titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 11.21mg of C3H5NaO3.
Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist
Expert Committee:(PA1)Pharmaceutical Analysis 1
USP28–NF23Page 1787
Phone Number:1-301-816-8379