Levocarnitine Tablets
DEFINITION
Levocarnitine Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of levocarnitine (C7H15NO3).
IDENTIFICATION
•  A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
•  B. Color Reaction
Analysis:  Dissolve 1 Tablet in 5 mL of water, filter, and add 5 mL of 1 N hydrochloric acid. Place 2 mL of the filtrate in a test tube and add a few drops of ammonium reineckate TS.
Acceptance criteria:  A red-violet precipitate is produced.
ASSAY
•  Procedure
Buffer:  0.05 M phosphate buffer, pH 4.5, prepared by dissolving 6.805 g of monobasic potassium phosphate in 1 L of water
Solution A:  Acetonitrile and Buffer (65:35). Adjust with phosphoric acid to a pH of 4.7, and mix.
Mobile phase:  See Table 1.
Table 1
Time
(min)
Acetonitrile
(%)
Solution A
(%)
Water
(%)
0 100 0 0
50 100 0 0
70 65 0 35
170 65 0 35
190 0 100 0
370 0 100 0
System suitability solution:  1.5 mg/mL of USP Levocarnitine RS and 7 µg/mL of USP Levocarnitine Related Compound A RS in water
Standard solution:  3 mg/mL of USP Levocarnitine RS in water
Sample solution:  Transfer 10 Tablets, accurately weighed, to a 500-mL volumetric flask, and add water to volume. Shake until the Tablets have disintegrated completely, and pass through a filter of 0.45-µm pore size. Dilute a portion of the filtrate quantitatively with water to a nominal concentration of about 3 mg/mL of levocarnitine.
Chromatographic system 
(See Chromatography 621, System Suitability.)
Mode:  LC
Detector:  UV 205 nm
Column:  3.9-mm × 30-cm; 10-µm packing L8
Flow rate:  1 mL/min
Injection size:  20 µL
System suitability 
Samples:  System suitability solution and Standard solution
Suitability requirements 
Resolution:  NLT 1.0 between levocarnitine related compound A (crotonoylbetaine) and levocarnitine, System suitability solution
Relative standard deviation:  NMT 2.0% for levocarnitine, Standard solution
Analysis 
Samples:  Standard solution and Sample solution
Calculate the percentage of the labeled amount of levocarnitine (C7H15NO3) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
rU== peak area of levocarnitine from the Sample solution
rS== peak area of levocarnitine from the Standard solution
CS== concentration of USP Levocarnitine RS in the Standard solution (mg/mL)
CU== nominal concentration of levocarnitine in the Sample solution (mg/mL)
Acceptance criteria:  90.0%–110.0%
PERFORMANCE TESTS
•  Dissolution 711
Medium:  Water; 900 mL
Apparatus 2:  75 rpm
Time:  30 min
Standard solution:  Known concentration of USP Levocarnitine RS in Medium
Sample solution:  Filtered portion of the solution under test, suitably diluted with Medium if necessary
Analysis 
Samples:  Standard solution and Sample solution
Proceed as directed in the Assay, making any necessary modifications.
Determine the percentage of the labeled amount of levocarnitine (C7H15NO3) dissolved:
Result = (rU/rS) × (CS × D × V/L) × 100
rU== peak area of levocarnitine in the Sample solution
rS== peak area of levocarnitine in the Standard solution
CS== concentration of USP Levocarnitine RS in the Standard solution (mg/mL)
V== volume of Medium, 900 mL
D== dilution factor for Sample solution
L== label claim (mg/Tablet)
Tolerances:  NLT 75% (Q) of the labeled amount of levocarnitine (C7H15NO3) is dissolved.
•  Uniformity of Dosage Units 905: Meet the requirements for Weight Variation
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in tight containers.
•  USP Reference Standards 11
USP Levocarnitine RS Click to View Structure
USP Levocarnitine Related Compound A RS
2-Propen-1-aminium, 3-carboxy-N,N,N-trimethyl-, chloride.
     C7H14ClNO2        179.65
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Topic/Question Contact Expert Committee
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Scientific Liaison
1-301-816-8328
(DS2010) Monographs - Dietary Supplements
711 Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison
1-301-816-8106
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USP35–NF30 Page 3667