Lysine Hydrochloride
C6H14N2O2·HCl 182.65
l-Lysine hydrochloride
[657-27-2].
(lye' seen hye'' droe klor' ide).
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C6H14N2O2·HCl 182.65
l-Lysine hydrochloride
[657-27-2].DEFINITION
Lysine Hydrochloride contains NLT 98.5% and NMT 101.5% of l-lysine hydrochloride (C6H14N2O2·HCl), calculated on the dried basis.
IDENTIFICATION
ASSAY
• Procedure
Sample:
90 mg of Lysine Hydrochloride
Blank:
Mix 3 mL of formic acid and 50 mL of glacial acetic acid.
Titrimetric system
(See Titrimetry 
541
.)
541.)
Mode:
Direct titration
Titrant:
0.1 N perchloric acid VS
Endpoint detection:
Potentiometric
Analysis:
Dissolve the Sample in 3 mL of formic acid and 50 mL of glacial acetic acid. Add 10 mL of mercuric acetate TS, and titrate with theTitrant. Perform the Blank determination.
Calculate the percentage of lysine hydrochloride (C6H14N2O2·HCl) in the Sample taken:
Result = {[(VS 
VB) × N × F]/W} × 100
VB) × N × F]/W} × 100| VS | = | = Titrant volume consumed by the Sample (mL) |
| VB | = | = Titrant volume consumed by the Blank (mL) |
| N | = | = actual normality of the Titrant (mEq/mL) |
| F | = | = equivalency factor, 91.33 mg/mEq |
| W | = | = Sample weight (mg) |
Acceptance criteria:
98.5%–101.5% on the dried basis
OTHER COMPONENTS
• Content of Chloride
Sample:
350 mg of Lysine Hydrochloride
Blank:
140 mL of water
Titrimetric system
(See Titrimetry 541.)
541.)
Mode:
Direct titration
Titrant:
0.1 N silver nitrate VS
Endpoint detection:
Visual
Analysis:
Transfer the Sample to a porcelain casserole, and add 140 mL of water and 1 mL of dichlorofluorescein TS. Titrate with the Titrant until the silver chloride flocculates and the mixture acquires a faint pink color. Perform the Blank determination.
Calculate the percentage of chloride (Cl) in the Sample taken:
Result = {[(VS VB) × N × F]/W} × 100
VB) × N × F]/W} × 100| VS | = | = Titrant volume consumed by the Sample (mL) |
| VB | = | = Titrant volume consumed by the Blank (mL) |
| N | = | = actual normality of the Titrant (mEq/mL) |
| F | = | = equivalency factor, 35.45 mg/mEq |
| W | = | = Sample weight (mg) |
Acceptance criteria:
19.0%–19.6%
IMPURITIES
• Residue on Ignition 281:
NMT 0.1%
281:
NMT 0.1%
• Chloride and Sulfate, Sulfate 221
221
Standard solution:
0.10 mL of 0.020 N sulfuric acid
Sample:
0.33 g of Lysine Hydrochloride
Acceptance criteria:
NMT 0.03%
• Iron 241:
NMT 30 ppm
241:
NMT 30 ppm
• Heavy Metals, Method I 231:
NMT 15 ppm
231:
NMT 15 ppm
• Related Compounds
Standard solution:
0.05 mg/mL of USP l-Lysine Hydrochloride RS in water. [Note—This solution has a concentration equivalent to 0.5% of that of the Sample solution. ]
Sample solution:
10 mg/mL of Lysine Hydrochloride in water
System suitability solution:
0.4 mg/mL each of USP l-Lysine Hydrochloride RS and USP Arginine Hydrochloride RS
Chromatographic system
Mode:
TLC
Adsorbent:
0.25-mm layer of chromatographic silica gel mixture
Application volume:
5 µL
Developing solvent system:
Isopropyl alcohol and ammonium hydroxide (7:3)
Spray reagent:
0.2 g of ninhydrin in a mixture of butyl alcohol and 2 N acetic acid (95:5)
System suitability
Suitability requirements:
The chromatogram of the System suitability solution exhibits two clearly separated spots.
Analysis
Samples:
Standard solution, System suitability solution, and Sample solution
Dry the plate between 100
and 105 until the ammonia completely disappears. Spray with Spray reagent, and heat between 100 and 105 for 15 min. Examine the plate under white light.
and 105 until the ammonia completely disappears. Spray with Spray reagent, and heat between 100 and 105 for 15 min. Examine the plate under white light.
Acceptance criteria:
Any secondary spot of the Sample solution is not larger or more intense than the principal spot of the Standard solution.
Individual impurities:
NMT 0.5%
Total impurities:
NMT 2.0%
SPECIFIC TESTS
• Optical Rotation, Specific Rotation 781S
781S
Sample solution:
80 mg/mL in 6 N hydrochloric acid
Acceptance criteria:
+20.4 to +21.4
to +21.4
• Loss on Drying 731:
Dry a sample at 105 for 3 h: it loses NMT 0.4% of its weight.
731:
Dry a sample at 105 for 3 h: it loses NMT 0.4% of its weight.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Huy T. Dinh, M.S.
Scientific Liaison 1-301-816-8594 |
(DS2010) Monographs - Dietary Supplements |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 3733