Lamivudine
(la miv' ue deen).
C8H11N3O3S 229.26 2(1H)-Pyrimidinone, 4-amino-1-[2-(hydroxymethyl)-1,3-oxathiolan-5-yl]-, (2R-cis)-; ()-1-[(2R,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine [134678-17-4]. DEFINITION
Lamivudine contains NLT 98.0% and NMT 102.0% of C8H11N3O3S, calculated on the anhydrous and solvent-free basis.
IDENTIFICATION
• B.
The retention time of the major peak of the Sample solution corresponds to that of the System suitability solution, as obtained in the test for Lamivudine Enantiomer.
ASSAY
• Procedure
Buffer:
1.9 g/L of ammonium acetate in water. Adjust with acetic acid to a pH of 3.8 ± 0.2 before final dilution.
Mobile phase:
Methanol and Buffer (5:95)
System suitability solution:
0.25 mg/mL of USP Lamivudine Resolution Mixture B RS in Mobile phase
Standard solution:
0.25 mg/mL of USP Lamivudine RS in Mobile phase
Sample solution:
0.25 mg/mL of Lamivudine in Mobile phase
Chromatographic system
Mode:
LC
Detector:
UV 277 nm
Column:
4.6-mm × 25-cm; packing L1
Column temperature:
35
Flow rate:
1 mL/min
Injection size:
10 µL
System suitability
Samples:
System suitability solution and Standard solution
[NoteThe relative retention times for lamivudine diastereomer and lamivudine are 0.9 and 1.0, respectively. ]
Suitability requirements
Resolution:
NLT 1.5 between lamivudine and lamivudine diastereomer, System suitability solution
Relative standard deviation:
NMT 2.0% for lamivudine, Standard solution
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of lamivudine (C8H11N3O3S) in the portion of Lamivudine taken:
Result = (rU/rS) × (CS/CU) × 100
Acceptance criteria:
98.0%102.0% on the anhydrous, solvent-free basis
IMPURITIES
• Organic Impurities, Lamivudine Enantiomer
Buffer:
7.7 g/L of ammonium acetate in water
Mobile phase:
Methanol and Buffer (5:95)
System suitability solution:
0.25 mg/mL of USP Lamivudine Resolution Mixture A RS in water
Sample solution:
0.25 mg/mL of Lamivudine in water
Chromatographic system
Mode:
LC
Detector:
UV 270 nm
Column:
4.6-mm × 25-cm; packing L45
Column temperature:
1530 (constant temperature)
Flow rate:
1 mL/min
Injection size:
10 µL
System suitability
Sample:
System suitability solution
[NoteThe relative retention times for lamivudine and lamivudine enantiomer are 1.0 and 1.2, respectively. ]
Suitability requirements
Resolution:
NLT 1.5 between lamivudine and lamivudine enantiomer
Analysis
Sample:
Sample solution
Calculate the percentage of the lamivudine enantiomer in the portion of Lamivudine taken:
Result = [rU/(rU + rS)] × 100
Acceptance criteria:
NMT 0.3%
• Organic Impurities, Other Related Compounds
Buffer, Mobile phase, Standard solution (Lamivudine), System suitability solution, Suitability requirements, and Chromatographic system:
Proceed as directed in the Assay.
Standard solution:
0.625 µg/mL of salicylic acid in Mobile phase
Sample solution:
0.25 mg/mL of Lamivudine in Mobile phase
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of salicylic acid in the portion of Lamivudine taken:
Result = (rU/rS) × (CS/CU) × 100
Calculate the percentage of other individual impurities in the portion of Lamivudine taken:
Result = (rU/rT) × 100
Acceptance criteria:
See Table 1.
Table 1
• Organic Impurities, Residual Solvents
Internal standard solution:
Dilute 1 mL of 2-pentanone with dimethyl sulfoxide and water (1:1) to 100.0 mL.
Standard solution:
Transfer 10 mL of Internal standard solution to a 100-mL volumetric flask. Add 100 µL of each of the following: dehydrated alcohol, isopropyl acetate, methanol, and triethylamine. Dilute with dimethyl sulfoxide and water (1:1) to volume.
Sample solution:
Transfer 5 g of Lamivudine to a 100-mL volumetric flask, add 10 mL of Internal standard solution, and dilute with dimethyl sulfoxide and water (1:1) to volume.
Chromatographic system
Mode:
GC
Detector:
Flame ionization
Column:
0.53-mm × 50-m column, coated with a 5-µm film of phase G1
Temperature
Injector:
150
Detector:
250
Column:
See Table 2.
Table 2
Injection size:
0.5 µL
Injection type:
Split flow rate, 320 mL/min
Carrier gas:
Hydrogen (at pressure 5 psig)
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of each residual solvent in the portion of Lamivudine taken:
Result = (RU/RS) × (CS/CU) × 100
Acceptance criteria:
See Table 3.
Table 3
SPECIFIC TESTS
• Water Determination, Method Ic 921:
NMT 0.2%
• Light Absorption
Mode:
UV-Vis
Sample solution:
50 mg/mL in water
Analytical wavelength:
440 nm
Cell:
4 cm
Acceptance criteria:
Absorptivity NMT 0.0015
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed, light-resistant containers. Store at room temperature.
Auxiliary Information
Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 3632
Pharmacopeial Forum: Volume No. 32(2) Page 346
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