» Aspartic Acid contains not less than 98.5 percent and not more than 101.5 percent of C4H7NO4, calculated on the dried basis.
Packaging and storage Preserve in well-closed containers, protected from light.
Identification, Infrared Absorption 197K.
Specific rotation 781S: between +24.0 and +26.0, at 20.
Test solution: 80 mg per mL, in 6 N hydrochloric acid.
Loss on drying 731 Dry it at 105 for 3 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281: not more than 0.1%.
Chloride 221 Dissolve 0.7 g in 10 mL of diluted nitric acid, and dilute with water to make 15 mL: the solution shows no more chloride than corresponds to 0.20 mL of 0.020 N hydrochloric acid (0.02%).
Sulfate 221 Dissolve 0.8 g in 4 mL of hydrochloric acid, and dilute with water to make 15 mL: the solution shows no more sulfate than corresponds to 0.25 mL of 0.020 N sulfuric acid (0.03%).
Iron 241: 0.001%.
Heavy metals, Method II 231: 0.001%.
Adsorbent: 0.25-mm layer of chromatographic silica gel mixture.
System suitability solution Dissolve 10 mg each of USP Aspartic Acid RS and glutamic acid, each accurately weighed, in 2 mL of ammonia TS, dilute with water to 25.0 mL, and mix.
Test solution Transfer 0.1 g of Aspartic Acid to a 10-mL volumetric flask, dissolve in 2 mL of 17% ammonia solution (prepared by diluting ammonium hydroxide, 6 in 10), dilute with water to volume, and mix.
Standard solution Transfer 5 mg of USP Aspartic Acid RS to a 100-mL volumetric flask, dissolve in 2 mL of 17% ammonia solution (prepared by diluting ammonium hydroxide, 6 in 10), dilute with water to volume, and mix.
Application volume: 5 µL.
Developing solvent system: a mixture of butyl alcohol, glacial acetic acid, and water (6:2:2).
Spray reagent Dissolve 0.2 g of ninhydrin in 100 mL of a mixture of butyl alcohol and 2 N acetic acid (95:5).
Procedure Proceed as directed for Thin-Layer Chromatography under Chromatography 621, except to dry the plate at 80 for 30 minutes, spray with Spray reagent, and heat at 80 for 30 minutes. Examine the plate under white light. The chromatogram obtained from the System suitability solution exhibits two clearly separated spots, and no secondary spot in the chromatogram of the Test solution is larger or more intense than the principal spot in the chromatogram of the Standard solution: not more than 0.5% of any individual impurity is found; and not more than 2.0% of total impurities is found.
Assay Transfer about 0.1 g of Aspartic Acid, accurately weighed, to a 125-mL flask, and dissolve in 50 mL of carbon dioxide-free water, heating slightly if necessary. Cool, add 0.1 mL of bromothymol blue TS, and titrate with 0.1 N sodium hydroxide VS until the color changes from yellow to blue. Perform a blank determination, and make any necessary correction (see Titrimetry 541). Each mL of 0.1 N sodium hydroxide is equivalent to 13.31 mg of C4H7NO4.
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USP32NF27 Page 1581Pharmacopeial Forum: Volume No. 31(5) Page 1345