Arginine
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L-Arginine.
L-Arginine [74-79-3].
»Arginine contains not less than 98.5percent and not more than 101.5percent of C6H14N4O2,as L-arginine,calculated on the dried basis.
Packaging and storage—
Preserve in well-closed containers.
Identification,
Infrared Absorption á197Kñ.
Specific rotation á781Sñ:
between +26.3
and +27.7.
and +27.7.
Test solution:
80mg per mL,in 6Nhydrochloric acid.
Loss on drying á731ñ—
Dry it at 105for 3hours:it loses not more than 0.5%of its weight.
for 3hours:it loses not more than 0.5%of its weight.
Residue on ignition á281ñ:
not more than 0.3%.
Chloride á221ñ—
A1.0-g portion shows no more chloride than corresponds to 0.70mLof 0.020Nhydrochloric acid (0.05%).
Sulfate á221ñ—
A1.0-g portion shows no more sulfate than corresponds to 0.30mLof 0.020Nsulfuric acid (0.03%).
Iron á241ñ:
0.003%.
Heavy metals,Method Iá231ñ:
0.0015%.
Chromatographic purity—
Adsorbent:
0.25-mm layer of chromatographic silica gel mixture.
Test solution—
Dissolve an accurately weighed quantity of Arginine in 2Nhydrochloric acid to obtain a solution having a concentration of 10mg per mL.Apply 5µL.
Standard solution—
Dissolve an accurately weighed quantity of USPL-Arginine RSin 0.1Nhydrochloric acid to obtain a solution having a known concentration of about 0.05mg per mL.Apply 5µL.[NOTE—This solution has a concentration equivalent to about 0.5%of that of the Test solution.]
System suitability solution—
Prepare a solution in 0.1Nhydrochloric acid containing 0.4mg each of USPL-Arginine RSand USPL-Lysine Hydrochloride RSper mL.Apply 5µL.
Spray reagent—
Dissolve 0.2g of ninhydrin in 100mLof a mixture of butyl alcohol and 2Nacetic acid (95:5).
Developing solvent system—
Prepare a mixture of isopropyl alcohol and ammonium hydroxide (70:30).
Procedure—
Proceed as directed for Thin-Layer Chromatographyunder Chromatography á621ñ.Dry the plate between 100and 105until the ammonia disappears completely.Spray with Spray reagent,and heat between 100and 105for about 15minutes.Examine the plate under white light.The chromatogram obtained from the System suitability solutionexhibits two clearly separated spots.Any secondary spot in the chromatogram obtained from the Test solutionis not larger or more intense than the principal spot in the chromatogram obtained from theStandard solution:not more than 0.5%of any individual impurity is found;and not more than 2.0%of total impurities is found.
and 105until the ammonia disappears completely.Spray with Spray reagent,and heat between 100and 105for about 15minutes.Examine the plate under white light.The chromatogram obtained from the System suitability solutionexhibits two clearly separated spots.Any secondary spot in the chromatogram obtained from the Test solutionis not larger or more intense than the principal spot in the chromatogram obtained from theStandard solution:not more than 0.5%of any individual impurity is found;and not more than 2.0%of total impurities is found.
Organic volatile impurities,Method Iá467ñ:
meets the requirements.
Solvent—
Use water.
Assay—
Transfer about 80mg of Arginine,accurately weighed,to a 125-mLflask,dissolve in a mixture of 3mLof formic acid and 50mLof glacial acetic acid,and titrate with 0.1Nperchloric acid VS,determining the endpoint potentiometrically.Perform a blank determination,and make any necessary correction.Each mLof 0.1Nperchloric acid is equivalent to 8.710mg of C6H14N4O2.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(DSN)Dietary Supplements:Non-Botanicals
USP28–NF23Page 175
Phone Number:1-301-816-8389