Packaging and storage—
Preserve in well-closed containers, and store at controlled room temperature.
Thin-layer chromatographic identification test 
201
—
Test solution—
Powder and transfer a portion of Tablets equivalent to about 40 mg of lysine hydrochloride to a 100-mL volumetric flask. Dilute with water to volume, mix, and filter. Use the filtrate.
Standard solution—
Dissolve an accurately weighed quantity of USP L-Lysine Hydrochloride RS in water to obtain a solution having a known concentration of about 0.4 mg per mL.
Developing solvent system—
Prepare a mixture of isopropyl alcohol and ammonium hydroxide (70:30).
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 in the chapter. Dry the plate between 100
and 105
until the ammonia disappears completely. Spray with
Spray reagent, and heat between 100
and 105
for about 15 minutes. Examine the plate under white light.
Assay—
Weigh and finely powder not fewer than 20 Tablets. Transfer about 75 mg of lysine hydrochloride, accurately weighed, to a 125-mL flask, and dissolve in 5 mL of
mercuric acetate TS with gentle heating. Cool, then add 50 mL of glacial acetic acid and 3 drops of
crystal violet TS, and titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 9.133 mg of
L-lysine hydrochloride (C
6H
14N
2O
2·HCl).
Auxiliary Information—
Staff Liaison :
Lawrence Evans, III, Ph.D., Scientist
Expert Committee : (DSN05) Dietary Supplements - Non-Botanicals
USP29–NF24 Page 2359
Pharmacopeial Forum : Volume No. 30(5) Page 1665
Phone Number : 1-301-816-8389
