Sodium Starch Glycolate

Starch carboxymethyl ether, sodium salt.
» Sodium Starch Glycolate is the sodium salt of a carboxymethyl ether of starch or of a cross-linked carboxymethyl ether of starch. It may contain not more than 7.0 percent of Sodium Chloride. The pH and assay requirements for Type A and Type B are set forth in the accompanying table.
pH % Sodium, combined as sodium starch glycolate
Type Min. Max. Min. Max.
A 5.5 7.5 2.8 4.2
B 3.0 5.0 2.0 3.4
Packaging and storage— Preserve in well-closed containers, preferably protected from wide variations in temperature and humidity, which may cause caking.
Labeling— Label it to indicate the botanical source of the starch from which it was derived, the cross-linking agent (if used), the pH range, and whether it is Type A or Type B.
Identification—
B: A slightly acidified solution of it is colored blue to violet by the addition of iodine and potassium iodide TS 1.
C: To a 2-mL portion of the solution prepared for the test for Limit of iron, add 4 mL of Potassium pyroantimonate solution. If necessary, rub the inside of the test tube with a glass rod. A white, crystalline precipitate is formed.
Potassium pyroantimonate solution—To 2 g of potassium pyroantimonate add 100 mL of water. Boil the solution for about 5 minutes, cool quickly, and add 10 mL of a solution of potassium hydroxide (3 in 20). Allow to stand for 24 hours, and filter.
D: Sodium Starch Glycolate imparts an intense yellow color to a nonluminous flame.
Microbial enumeration tests 61 and Tests for specified microorganisms 62— It meets the requirements of the tests for absence of Salmonella species and Escherichia coli.
pH 791— Disperse 1 g in 30 mL of water. The pH of the resulting suspension is either between 5.5 and 7.5 for Type A or between 3.0 and 5.0 for Type B.
Loss on drying 731— Dry it at 130 for 90 minutes: it loses not more than 10.0% of its weight.
Limit of iron—
Standard solution— Dissolve 863.4 mg of ferric ammonium sulfate [FeNH4(SO4)2·12H2O] in water, add 25 mL of 2 N sulfuric acid, dilute with water to 500.0 mL, and mix. Pipet 10 mL of this solution into a 100-mL volumetric flask, dilute with water to volume, and mix. Pipet 5 mL of this solution into a 100-mL volumetric flask, dilute with water to volume, and mix. This solution contains the equivalent of 1.0 µg of iron per mL.
Test solution— [note—Reserve a portion of this solution for Identification test C.] Place 2.5 g in a silica or platinum crucible, and add 2 mL of 10 N sulfuric acid. Heat on a water bath, then cautiously raise the temperature progressively over an open flame. Ignite, preferably in a muffle furnace, at 600 ± 25. Continue heating until all black particles have disappeared. Cool, add a few drops of 2 N sulfuric acid, and heat and ignite as above. Add a few drops of 2 M ammonium carbonate, evaporate to dryness, and ignite as above. Cool, dissolve the residue in 50 mL of water, and mix.
Procedure— Treat the Test solution and the Standard solution as follows. Transfer 10 mL of the solution to a suitable beaker, add 2 mL of citric acid solution (1 in 5) and 0.1 mL of thioglycolic acid, and mix. Render the solution alkaline, using litmus paper as an external indicator, by the addition of ammonium hydroxide, dilute with water to 20 mL, and mix. Allow the solutions to stand for 5 minutes: the color of the solution from the Test solution is a shade of pink no deeper than that of the solution from the Standard solution (0.002%).
Limit of sodium chloride— Transfer to a beaker about 500 mg of Sodium Starch Glycolate, accurately weighed, and suspend in 100 mL of water. Add 1 mL of nitric acid. Titrate with 0.1 N silver nitrate VS, determining the endpoint potentiometrically, using a suitable silver-based indicator electrode and a double-junction reference electrode containing a 10% potassium nitrate filling solution in the outer jacket and a standard filling solution in the inner jacket. Each mL of 0.1 N silver nitrate is equivalent to 5.844 mg of sodium chloride.
Limit of sodium glycolate— [note—Conduct this test without exposure to daylight. Use low-actinic glassware.]
Standard solution— Transfer 310 mg of glycolic acid, previously dried over phosphorus pentoxide in a desiccator at room temperature overnight, to a 500-mL volumetric flask, and dissolve in and dilute with water to volume. Transfer 5.0 mL of this solution to a 100-mL beaker, add 4 mL of 6 N acetic acid, and allow to stand for about 30 minutes. Add 50 mL of acetone and 1 g of sodium chloride, mix, and pass through fast filter paper moistened with acetone into a 100-mL volumetric flask. Rinse the beaker and filter paper with acetone. Combine the filtrate and washings, dilute with acetone to volume, and mix. Allow to stand for 24 hours without shaking. Use the clear supernatant as the Standard solution.
Test solution— Transfer 200 mg, accurately weighed, to a 100-mL beaker Add 4 mL of 6 N acetic acid and 5 mL of water. Stir until dissolution is complete (about 10 minutes). Add 50 mL of acetone and 1 g of sodium chloride, mix, and pass through fast filter paper moistened with acetone into a 100-mL volumetric flask. Rinse the beaker and filter paper with acetone. Combine the filtrate and washings, dilute with acetone to volume, and mix. Allow to stand for 24 hours without shaking. Use the clear supernatant as the Test solution.
Procedure— Treat the Test solution and the Standard solution as follows. Heat 2.0 mL of the solution on a water bath for 20 minutes to remove the acetone. Cool to room temperature. Prepare a 2,7-dihydroxynaphthalene solution as follows. Dissolve 10 mg of 2,7-dihydroxynaphthalene in 100 mL of sulfuric acid, allow to stand until decolorized, and use within 2 days. Add 20.0 mL of this 2,7-dihydroxynaphthalene solution to the solution under test, mix, and heat on a water bath for 20 minutes. Cool under running water, and quantitatively transfer to a 25-mL volumetric flask. Maintain the flask under running water, and dilute with sulfuric acid to volume. Within 10 minutes determine the absorbance of the solution at 540 nm with a suitable spectrophotometer, using water as the blank: the absorbance of the solution from the Test solution is not more than that of the solution from the Standard solution (2.0%).
Assay— Transfer about 1 g to a conical flask, add 20 mL of 80% alcohol, stir for 10 minutes, and filter. Repeat the extraction until the chloride has been completely extracted, as shown by a test with silver nitrate. Dry the insoluble portion at 105 to constant weight, and transfer an accurately weighed portion (about 700 mg) of the dried 80% alcohol-insoluble portion to a suitable flask, add 80 mL of glacial acetic acid, heat the mixture under reflux on a boiling water bath for 2 hours, cool to room temperature, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Calculate the percentage of sodium combined in the form of sodium starch glycolate by the formula:
100(22.99)VN/W
in which V is the volume, in mL, of the perchloric acid consumed; N is the normality of the perchloric acid; and W is the weight, in mg, of the dried alcohol-insoluble residue taken for the Assay.
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Topic/Question Contact Expert Committee
Monograph Kevin T. Moore, Ph.D.
Scientist
1-301-816-8369		 (EM205) Excipient Monographs 2
Reference Standards Lili Wang, Technical Services Scientist
1-301-816-8129
RSTech@usp.org
61 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
1-301-816-8339		 (MSA05) Microbiology and Sterility Assurance
62 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
1-301-816-8339		 (MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 1345
Pharmacopeial Forum: Volume No. 31(5) Page 1524
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.