Carboxymethylcellulose Sodium

Cellulose,carboxymethyl ether,sodium salt.
Cellulose carboxymethyl ether sodium salt [9004-32-4].
»Carboxymethylcellulose Sodium is the sodium salt of a polycarboxymethyl ether of cellulose.It contains not less than 6.5percent and not more than 9.5percent of sodium (Na),calculated on the dried basis.
Packaging and storage— Preserve in tight containers.
Labeling— Label it to indicate the viscosity in solutions of stated concentrations.
Identification— Add about 1g of powdered Carboxymethylcellulose Sodium to 50mLof water,while stirring to produce a uniform dispersion.Continue the stirring until a clear solution is produced,and use the solution for the following tests.
A: To 1mLof the solution,diluted with an equal volume of water,in a small test tube,add 5drops of 1-naphthol TS.Incline the test tube,and carefully introduce down the side of the tube 2mLof sulfuric acid so that it forms a lower layer:a red-purple color develops at the interface.
B: To 5mLof the solution add an equal volume of barium chloride TS:a fine,white precipitate is formed.
C: Aportion of the solution responds to the tests for Sodium á191ñ.
Viscosity á911ñ— Determine the viscosity in a water solution at the concentration stated on the label.Using undried Carboxymethylcellulose Sodium,weigh accurately the amount that,on the dried basis,will provide 200g of solution of the stated concentration.Add the substance in small amounts to about 180mLof stirred water contained in a tared,wide-mouth bottle,continue stirring rapidly until the powder is well wetted,add sufficient water to make the mixture weigh 200g,and allow to stand,with occasional stirring,until solution is complete.Adjust the temperature to 25±0.2,and determine the viscosity,using a rotational type of viscosimeter,making certain that the system reaches equilibrium before taking the final reading.The viscosity of solutions of 2%or higher concentration is not less than 80.0%and not more than 120.0%of that stated on the label;the viscosity of solutions of less than 2%concentration is not less than 75.0%and not more than 140.0%of that stated on the label.
pHá791ñ: between 6.5and 8.5in a solution (1in 100).
Loss on drying á731ñ— Dry it at 105for 3hours:it loses not more than 10.0%of its weight.
Heavy metals,Method IIá231ñ— Determine as directed in the test for Heavy metalsunder Methylcellulose,using a 1.0-g specimen:the limit is 20µg per g.
Organic volatile impurities,Method IVá467ñ: meets the requirements.
Assay— Transfer to a beaker about 500mg of Carboxymethylcellulose Sodium,accurately weighed,add 80mLof glacial acetic acid,heat the mixture on a boiling water bath for 2hours,cool to room temperature,and titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Each mLof 0.1Nperchloric acid is equivalent to 2.299mg of Na.
Auxiliary Information— Staff Liaison:Justin Lane,B.S.,Scientific Associate
Expert Committee:(EMC)Excipients:Monograph Content
USP28–NF23Page 358
Pharmacopeial Forum:Volume No.28(3)Page 867
Phone Number:1-301-816-8323