Levetiracetam
C8H14N2O2 170.21
1-Pyrrolidineacetamide,
-ethyl-2-oxo-, (S)-;
(
)-(S)--Ethyl-2-oxo-1-pyrrolidineacetamide
[102767-28-2].
(lee'' va tye ra' se tam).
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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
• 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
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. ]
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
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
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
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. ]
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-ola | 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%
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
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. ]
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
11
USP Levetiracetam RS 
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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.
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
(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
(S)-2-Aminobutanamide hydrochloride.
C4H10N2O·HCl 138.6
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Hariram Ramanathan, M.S.
Associate Scientific Liaison 1-301-816-8313 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 3659
Pharmacopeial Forum: Volume No. 36(5) Page 1147