Sodium Polystyrene Sulfonate Suspension
»Sodium Polystyrene Sulfonate Suspension is a suspension of Sodium Polystyrene Sulfonate in an aqueous vehicle containing a suitable quantity of sorbitol.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of sorbitol (C6H14O6),and exchanges not less than 110mg and not more than 135mg of potassium for each g of the labeled amount of sodium polystyrene sulfonate.
Packaging and storage— Preserve in well-closed containers,protected from freezing and from excessive heat.
Labeling— Label it to state the quantity of sorbitol in a given volume of Suspension.
Microbial limits á61ñ— Its total aerobic microbial count does not exceed 100cfu per mL,its total combined molds and yeasts count does not exceed 100cfu per mL,and it meets the requirements of the test for absence of Pseudomonas aeruginosa.
Sodium content—
Sodium solution andStandard graph— Prepare as directed in the test for Sodium contentunder Sodium Polystyrene Sulfonate.
Procedure— Transfer an accurately measured quantity of Suspension,freshly mixed and free from air bubbles,equivalent to about 1g of sodium polystyrene sulfonate,to a suitable crucible,heat at 80until dry,and ash the residue with a slight excess of sulfuric acid.Proceed as directed for Procedurein the test for Sodium contentunder Sodium Polystyrene Sulfonate,beginning with “Add 1mLof nitric acid.”Calculate the percentage of sodium taken by the formula:
A/L,
in which Ais the quantity,in mg,of sodium found per liter,and Lis the quantity,in g,of sodium polystyrene sulfonate in the portion of Suspension taken,based on the labeled amount:the sodium content is not less than 9.4%and not more than 11.5%.
Potassium exchange capacity—
Potassium solution,Sodium solution,andStandard graph— Prepare as directed in the test for Potassium exchange capacityunder Sodium Polystyrene Sulfonate.
Procedure— Transfer an accurately measured quantity of Suspension,freshly mixed and free from air bubbles,equivalent to about 1.6g of sodium polystyrene sulfonate,to a suitable glass-stoppered flask,add 100.0mLof Potassium solution,shake by mechanical means for 15minutes,filter,and discard the first 20mLof the filtrate.Proceed as directed for Procedurein the test for Potassium exchange capacityunder Sodium Polystyrene Sulfonate,beginning with “Pipet 5mLof the filtrate.”Calculate the quantity,in mg,of potassium adsorbed on each g of the sodium polystyrene sulfonate taken by the formula:
(X-20Y)/L,
in which Xis the quantity,in mg,of potassium in 100mLof Potassium solutionbefore exchange;Yis the quantity,in mg,of potassium per liter as interpolated from the Standard graph;and Lis the labeled quantity,in g,of sodium polystyrene sulfonate in the portion of Suspension taken.
Assay for sorbitol—
Mobile phase,Resolution solution,Standard preparation,andChromatographic system— Proceed as directed in the Assayunder Sorbitol(see NFmonograph).
Assay preparation— Dilute an accurately measured volume of Suspension,freshly mixed and free from air bubbles,quantitatively with water to obtain a solution containing about 4.8mg of sorbitol per mL.Filter,and use the filtrate as the Assay preparation.
Procedure— Separately inject equal volumes (about 20µL)of the Assay preparationand the Standard preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Proceed as directed for Procedurein the Assayunder Sorbitol(see NFmonograph).Calculate the quantity,in g,of C6H14O6,in each mLof the Suspension taken by the formula:
(L/D)(C)(rU/rS),
in which Lis the labeled quantity,in g,of sorbitol in each mLof Suspension;Dis the quantity,in mg,of sorbitol in each mLof the Assay preparationbased on the labeled quantity and the extent of dilution;Cis the concentration,in mg per mL,of USP Sorbitol RSin the Standard preparation;and rUand rSare the peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(RMI)Radiopharmaceuticals and Medical Imaging Agents
USP28–NF23Page 1793
Phone Number:1-301-816-8305