Levetiracetam LEV CAS 102767-28-2 Assay 98.0%~102.0% USP EP Standard

Levetiracetam
C8H14N2O2 170.21
1-Pyrrolidineacetamide, -ethyl-2-oxo-, (S)-;
()-(S)--Ethyl-2-oxo-1-pyrrolidineacetamide [102767-28-2].
DEFINITION
Levetiracetam contains NLT 98.0% and NMT 102.0% of C8H14N2O2, calculated on the anhydrous and solvent-free basis.
IDENTIFICATION
• A. Infrared Absorption <197K>
• B. The retention time of the major peak for levetiracetam from the Sample solution corresponds to that of the levetiracetam S-enantiomer from the System suitability solution, as obtained in the test for Limit of Levetiracetam R-Enantiomer.
ASSAY
• Procedure
Buffer: 2.7 g/L of monobasic potassium phosphate in water. Adjust with 2% aqueous potassium hydroxide (w/v) to a pH of 5.5.
Solution A: Acetonitrile and Buffer (1:19)
Solution B: Acetonitrile
Mobile phase: See the gradient table below.
Time (min) Solution A (%) Solution B (%)
0 100 0
3 100 0
20 71 29
System suitability solution: 0.2 mg/mL of USP Levetiracetam RS and 0.08 mg/mL of USP Levetiracetam Related Compound A RS in Solution A. Prepare by first dissolving the required amount of USP Levetiracetam RS in a suitable volumetric flask. Add 10% of the flask volume of 0.1 N potassium hydroxide. Let the mixture react at room temperature for about 15 min, and then neutralize by adding 0.1 N hydrochloric acid at 10% of the flask volume. Add the required amount of USP Levetiracetam Related Compound A RS, sonicate to dissolve, dilute with Solution A to volume, and mix.
Standard solution: 0.1 mg/mL of USP Levetiracetam RS in Solution A
Sample solution: 0.1 mg/mL of Levetiracetam in Solution A
Chromatographic system
(See Chromatography <621>, System Suitability.)
Mode: LC
Detector: UV 205 nm
Column: 4.6-mm × 15-cm; packing L1
Flow rate: 0.9 mL/min
Injection size: 10 µL
System suitability
Sample: System suitability solution
[Note-The relative retention times are given in Impurity Table 1.]
Suitability requirements
Relative standard deviation: NMT 1.0%
[Note-If system suitability criteria cannot be met, it is recommended that the column temperature be maintained at 20 to stabilize the system.]
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of C8H14N2O2 in the portion of Levetiracetam taken:
Result = [(rU/rS) × (CS/CU) × 100] F
rU = peak response of levetiracetam from the Sample solution
rS = peak response of levetiracetam from the Standard solution
CS = concentration of USP Levetiracetam RS in the Standard solution (mg/mL)
CU = concentration of Levetiracetam in the Sample solution (mg/mL)
F = percentage of levetiracetam R-enantiomer from the test for Limit of Levetiracetam R-Enantiomer
Acceptance criteria: 98.0%-102.0% on the anhydrous and solvent-free basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition <281>: NMT 0.1%
• Heavy Metals, Method II <231>: 20 ppm
Organic Impurities
• Procedure 1: Limit of Levetiracetam Related Compound B
[Note-Perform this test only if levetiracetam related compound B is a known process impurity.]
Buffer: 1.22 g of sodium 1-decanesulfonate in 1 L of water containing about 1.3 mL of phosphoric acid. Adjust with 20% (w/v) potassium hydroxide to a pH of 3.0.
Mobile phase: Acetonitrile and Buffer (3:17)
System suitability solution: 2 mg/mL of USP Levetiracetam Related Compound B RS in Mobile phase
Standard solution: 0.002 mg/mL of USP Levetiracetam Related Compound B RS in Mobile phase
Sample solution: 2.0 mg/mL of Levetiracetam in Mobile phase
Chromatographic system
(See Chromatography 621, System Suitability.)
Mode: LC
Detector: UV 200 nm
Column: 4.6-mm × 25-cm; packing L1
Flow rate: 1.0 mL/min
Injection size
System suitability: 10 µL
Analysis: 50 µL
System suitability
Sample: System suitability solution
[Note-The retention time for levetiracetam related compound B is 9 min.]
Suitability requirements
Tailing factor: NMT 3.0
[Note-If a significant tailing of the levetiracetam related compound B peak is observed (greater than 3.0), it is recommended that the column temperature be maintained at 27 to stabilize the system.]
Relative standard deviation: NMT 2.0%
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of levetiracetam related compound B in the portion of Levetiracetam taken:
Result = (rU/rS) × (CS/CU) × (Mr1/Mr2) × 100
rU = peak response of levetiracetam related compound B from the Sample solution
rS = peak response of levetiracetam related compound B from the Standard solution
CS = concentration of USP Levetiracetam Related Compound B RS in the Standard solution (mg/mL)
CU = concentration of Levetiracetam in the Sample solution (mg/mL)
Mr1 = molecular weight of levetiracetam related compound B free base, 102.1
Mr2 = molecular weight of levetiracetam related compound B, 138.6
Acceptance criteria: NMT 0.10%
[Note-The amount of levetiracetam related compound B measured is to be included in the total impurities in the test for Organic Impurities, Procedure 2.]
• Procedure 2
Buffer, Solution A, Solution B, Mobile phase, System suitability solution, and Chromatographic system: Proceed as directed in the Assay.
Standard solution: 0.005 mg/mL of USP Levetiracetam RS in Solution A
Sample solution: 5 mg/mL of Levetiracetam in Solution A
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Levetiracetam taken:
Result = (rU/rS) × (CS/CU) × (1/F) × 100
rU = peak response of each impurity from the Sample solution
rS = peak response of levetiracetam from the Standard solution
CS = concentration of USP Levetiracetam RS in the Standard solution (mg/mL)
CU = concentration of Levetiracetam in the Sample solution (mg/mL)
F = relative response factor (see Impurity Table 1)
[Note-Disregard any peak with a relative retention time of 0.19 or less.]
Acceptance criteria
Individual impurities: See Impurity Table 1.
Total impurities: NMT 0.4%
Impurity Table 1
Name Relative Retention Time Relative Response Factor Acceptance Criteria, NMT (%)
Pyridin-2-ol a 0.37 1.0 0.025
Levetiracetam acidb 0.62 1.2 0.3
Levetiracetam 1.00 - -
Levetiracetam related compound Ac 1.25 0.35 0.05
Any individual unspecified impurity - 1.0 0.05
a Not included in the Total impurities limit.
b (S)-2-(2-Oxopyrrolidin-1-yl)butanoic acid. Included in the Total impurities limit.
c (S)-N-(1-Amino-1-oxobutan-2-yl)-4-chlorobutanamide. Included in the Total impurities limit only if levetiracetam related compound B is a known process impurity.
SPECIFIC TESTS
• Water Determination, Method Ia <921>: NMT 0.5%
• Limit of Levetiracetam R-Enantiomer
Mobile phase: n-Hexane and dehydrated alcohol (4:1)
System suitability solution: 0.1 mg/mL of USP Levetiracetam Racemic Mixture RS in Mobile phase
Standard solution: 0.05 mg/mL of USP Levetiracetam RS in Mobile phase
Sample solution: 10 mg/mL of Levetiracetam in Mobile phase
Chromatographic system
(See Chromatography <621>, System Suitability.)
Mode: LC
Detector: UV 215 nm
Column: 4.6-mm × 25-cm; 10-µm packing L51
Flow rate: 1.0 mL/min
Injection size: 20 µL
System suitability
Sample: System suitability solution
[Note-The relative retention times for levetiracetam R-enantiomer and levetiracetam S-enantiomer are 0.55 and 1.0, respectively.]
Suitability requirements
Resolution: NLT 4.0 between the R- and S-enantiomers
[Note-If a loss of resolution (less than 4.0) is observed, it is recommended that the column temperature be maintained at 25 to stabilize the system.]
Analysis
Samples: Standard solution and Sample solution
Calculate the percentage of levetiracetam R-enantiomer in the portion of Levetiracetam taken:
Result = (rU/rS) × (CS/CU) × 100
rU = peak response of levetiracetam R-enantiomer from the Sample solution
rS = peak response of levetiracetam from the Standard solution
CS = concentration of USP Levetiracetam RS in the Standard solution (mg/mL)
CU = concentration of Levetiracetam in the Sample solution (mg/mL)
Acceptance criteria: NMT 0.8%
ADDITIONAL REQUIREMENTS
• Packaging and Storage: Preserve in well-closed containers, and store at room temperature.
• USP Reference Standards <11>
USP Levetiracetam RS
USP Levetiracetam Racemic Mixture RS
A 1:1 mixture of levetiracetam S-enatiomer-(2S)-2-(2-oxopyrrolidin-1-yl)butanamide and levetiracetam R-enantiomer (2R)-2-(2-oxopyrrolidin-1-yl)butanamide.
USP Levetiracetam Related Compound A RS
(S)-N-(1-Amino-1-oxobutan-2-yl)-4-chlorobutanamide.
C8H14ClNO3 207.65
USP Levetiracetam Related Compound B RS
(S)-2-Aminobutanamide hydrochloride.
C4H10N2O·HCl 138.6