Anhydrous 132.12 [70-47-3].
» Asparagine is anhydrous, or contains one molecule of water of hydration. It contains not less than 98.0 percent and not more than 101.5 percent of C4H8N2O3, as l-asparagine, calculated on the dried basis.
Packaging and storage Preserve in well-closed, light-resistant containers. Store at room temperature.
Labeling Label it to indicate whether it is anhydrous or the monohydrate.
Identification, Infrared Absorption 197K. [noteUse USP Asparagine Anhydrous RS and USP Asparagine Monohydrate RS for the evaluation of the anhydrous and monohydrate forms of Asparagine, respectively.]
Specific rotation 781S: between +33.0 and +36.5, measured at 20.
Test solution: 10 mg per mL in 6 N hydrochloric acid.
Microbial enumeration tests 61 and Tests for specified microorganisms 62 The total aerobic microbial count does not exceed 1000 cfu per g, and the total combined molds and yeasts count does not exceed 100 cfu per g.
Loss on drying 731 Dry it at 130 for 3 hours: the anhydrous form loses not more than 1.0% of its weight, and the monohydrate loses between 11.5% and 12.5% of its weight.
Residue on ignition 281: not more than 0.1%, determined on 1.0 g.
Lead 251 Prepare a Test Preparation using a 1-g portion of Asparagine, and use 5 mL of Diluted Standard Lead Solution (5 µg of Pb) for the test: the limit is 5 µg per g.
Adsorbent: 0.25-mm layer of chromatographic silica gel mixture.
Test solution: 10 mg per mL.
Standard solution Prepare a solution of USP Asparagine Anhydrous RS or USP Asparagine Monohydrate RS in water having a known concentration of about 0.05 mg per mL. [noteUse USP Asparagine Anhydrous RS and USP Asparagine Monohydrate RS for the evaluation of the anhydrous and monohydrate forms of Asparagine, respectively.]
Application volume: 5 µL.
Developing solvent system: a mixture of butyl alcohol, water, and glacial acetic acid (3:1:1).
Spray reagent Dissolve 0.2 g of ninhydrin in 100 mL of a mixture of butyl alcohol and glacial acetic acid (95:5).
Procedure Proceed as directed for Thin-Layer Chromatography under Chromatography 621, and then dry the plate at 80 for 30 minutes. Spray the plate with the Spray reagent, heat at 80 for 10 minutes, and examine under white light: no secondary spot in the chromatogram obtained from the Test solution is larger or more intense than the principal spot in the chromatogram obtained from the Standard solution (0.5%); and not more than 1.0% of total impurities is found.
Assay Dissolve about 130 mg of Asparagine, accurately weighed, in 3 mL of formic acid and 50 mL of glacial acetic acid, and titrate with 0.1 N perchloric acid VS (see Titrimetry 541), determining the endpoint potentiometrically. Perform a blank determination, and make any necessary corrections. Each mL of 0.1 N perchloric acid is equivalent to 13.21 mg of C4H8N2O3, calculated on the dried basis.
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USP32NF27 Page 1168Pharmacopeial Forum: Volume No. 31(1) Page 87