Lamivudine and Zidovudine Tablets
DEFINITION
Lamivudine and Zidovudine Tablets contains NLT 90.0% and NMT 110.0% of the labeled amount of lamivudine (C8H11N3O3S) and zidovudine (C10H13N5O4).
IDENTIFICATION
• The retention times of the lamivudine and zidovudine peaks of the Sample solution correspond to those of the Standard solution, as obtained in the Assay.
ASSAY
• Procedure
Solution A:
25 mM of ammonium acetate. Adjust with glacial acetic acid to a pH of 4.0.
Solution B:
Methanol
Solution C:
Acetonitrile
Mobile phase:
See Table 1.
Table 1
| Time (min) |
Solution A (%) |
Solution B (%) |
Solution C (%) |
|---|---|---|---|
| 0 | 95 | 5 | 0 |
| 15.0 | 95 | 5 | 0 |
| 30.0 | 70 | 30 | 0 |
| 38.0 | 70 | 30 | 0 |
| 38.1 | 0 | 0 | 100 |
| 45.0 | 0 | 0 | 100 |
| 45.1 | 95 | 5 | 0 |
| 60.0 | 95 | 5 | 0 |
Diluent:
Solution A and Solution B (19:1)
System suitability solution:
0.17 mg/mL of USP Lamivudine Resolution Mixture B RS in Diluent
Standard solution:
0.15 mg/mL of USP Lamivudine RS and 0.30 mg/mL of USP Zidovudine RS in Diluent
Sample stock solution:
Transfer a counted number of Tablets, equivalent to 1500 mg of zidovudine and 750 mg of lamivudine, into a 500-mL volumetric flask. Add 250 mL of water, and disintegrate completely by shaking for a minimum of 15 min. Dilute with water to volume, and mix.
Sample solution:
Pass a portion of the Sample stock solution through a filter of 0.45-µm pore size, discarding the first 2–3 mL. Further dilute the filtrate to obtain 0.15 mg/mL of lamivudine and 0.30 mg/mL of zidovudine in Diluent.
Chromatographic system
Mode:
LC
Detector:
UV 270 nm
Column:
3-mm × 25-cm; packing L1
Flow rate:
0.5 mL/min
Injection size:
10 µL
System suitability
Samples:
System suitability solution and Standard solution [Note—The relative retention times for lamivudine diastereomer and lamivudine are 0.50 and 0.52, respectively. ]
Suitability requirements
Resolution:
NLT 1.5 between lamivudine diastereomer and lamivudine, System suitability solution
Relative standard deviation:
NMT 2.0% for zidovudine and lamivudine, Standard solution
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of the labeled amount of lamivudine (C8H11N3O3S) and zidovudine (C10H13N5O4) in the portion of Tablets taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response of zidovudine or lamivudine from the Sample solution |
| rS | = | = peak response of zidovudine or lamivudine from the Standard solution |
| CS | = | = concentration of USP Zidovudine RS or USP Lamivudine RS in the Standard solution (mg/mL) |
| CU | = | = nominal concentration of zidovudine or lamivudine in the Sample solution (mg/mL) |
Acceptance criteria:
90.0%–110.0%
PERFORMANCE TESTS
• Dissolution 
711
711
Test 1
Medium:
0.1 N hydrochloric acid; 900 mL, deaerated
Apparatus 2:
75 rpm
Time:
15 min
Lamivudine response factor solutions:
0.167 mg/mL of USP Lamivudine RS in Medium. [Note—Prepare in duplicate. ]
Zidovudine response factor solutions:
0.333 mg/mL of USP Zidovudine RS in Medium. [Note—Prepare in duplicate. ]
Sample solution:
Pass a portion of the solution under test through a suitable filter (PTFE, PVDF, or equivalent) of 0.45-µm pore size.
Detector:
UV 240–300 nm
Blank:
Medium
Cell length:
0.02-cm flowcell
Analysis:
The calculations of the percentages dissolved are done using a multicomponent analysis software.
Tolerances:
NLT 85% (Q) of the labeled amount of zidovudine and lamivudine is dissolved.
Test 2:
If the product complies with this test, the labeling indicates that it meets USP Dissolution Test 2.
Medium:
0.1 N hydrochloric acid; 900 mL
Apparatus 2:
75 rpm
Time:
30 min
Buffer solution:
7.7 g/L of ammonium acetate in water
Mobile phase:
Acetonitrile and Buffer solution (1:9)
Standard stock solution:
1.4 mg/mL of USP Lamivudine RS and 2.8 mg/mL of USP Zidovudine RS in Medium. A small amount of methanol, NMT 20% of the final volume, can be used to dissolve both compounds.
Standard solution:
0.168 mg/mL of lamivudine and 0.336 mg/mL of zidovudine in Medium, from the Standard stock solution
Sample solution:
Pass a portion of the solution under test through a suitable filter.
Chromatographic system
Mode:
LC
Detector:
UV 270 nm
Column:
4.6-mm × 15-cm; packing L1
Column temperature:
40
Flow rate:
1.2 mL/min
Injection size:
10 µL
System suitability
Sample:
Standard solution
Suitability requirements
Column efficiency:
NLT 1500 theoretical plates for lamivudine and NLT 3000 theoretical plates for zidovudine
Tailing factor:
NMT 2.0 for lamivudine and zidovudine
Relative standard deviation:
NMT 2.0% for zidovudine and lamivudine
Calculate the percentages of lamivudine (C8H11N3O3S) and zidovudine (C10H13N5O4) dissolved:
Result = (rU/rS) × (CS/L) × V × 100
| rU | = | = peak response for lamivudine or zidovudine from the Sample solution |
| rS | = | = peak response for lamivudine or zidovudine from the Standard solution |
| CS | = | = concentration of lamivudine or zidovudine in the Standard solution (mg/mL) |
| L | = | = label claim for lamivudine or zidovudine (mg/Tablet) |
| V | = | = volume of Medium, 900 mL |
Tolerances:
NLT 80% (Q) of the labeled amount of zidovudine and lamivudine is dissolved.
• Uniformity of Dosage Units 905:
Meet the requirements for zidovudine and lamivudine
905:
Meet the requirements for zidovudine and lamivudine
IMPURITIES
• Organic Impurities
Solution A, Solution B, Solution C, Mobile phase, Diluent, System suitability solution, Sample solution, Chromatographic system, and System suitability:
Proceed as directed in the Assay.
Analysis
Sample:
Sample solution
Calculate the percentage of each lamivudine related impurity in the portion of Tablets taken:
Result = (rU/rT) × 100
| rU | = | = peak response of each individual impurity from the Sample solution |
| rT | = | = sum of the peak responses of lamivudine and all lamivudine related impurities from the Sample solution |
Calculate the percentage of each zidovudine related impurity and unidentified impurity in the portion of Tablets taken:
Result = (rU/rT) × (1/F) × 100
| rU | = | = peak response of each individual impurity from the Sample solution |
| rT | = | = sum of the peak responses of zidovudine, all zidovudine related impurities, and unidentified impurities from the Sample solution |
| F | = | = relative response factor (see Table 2) |
Acceptance criteria:
See Table 2.
Table 2
| Name | Relative Retention Time |
Relative Response Factor |
Acceptance Criteria, NMT (%) |
|---|---|---|---|
| Lamivudine-(cytosine)a | 0.11 | 1.0 | —* |
| Lamivudine-(uracil)b | 0.14 | 1.0 | —* |
| Lamivudine-(carboxylic acid)c | 0.17 | 1.0 | 0.3 |
| Lamivudine-(S-sulfoxide)d | 0.20 | 1.0 | —* |
| Lamivudine-(R-sulfoxide)e | 0.22 | 1.0 | —* |
| Zidovudine related compound Cf | 0.27 | 1.7 | 1.5 |
| Lamivudine diastereomerg | 0.50 | 1.0 | 0.2 |
| Lamivudine | 0.52 | — | — |
| Zidovudine-(thymidine)h | 0.60 | 1.0 | —* |
| Lamivudine-(uracil derivative)i | 0.70 | 1.0 | —* |
| Lamivudine-(salicylic acid)j | 0.80 | 1.0 | —* |
| Zidovudine | 1.00 | — | — |
| Zidovudine related compound Bk | 1.10 | 1.0 | —* |
| Individual unidentified impurity | — | 1.0 | 0.1 |
| Total lamivudine related impurities (the limit includes all lamivudine related impurities) | — | — | 0.6 |
| Total zidovudine related impurities (the limit includes individual unidentified impurities) | — | — | 2.0 |
|
a
4-Aminopyrimidin-2(1H)-one.
b
Pyrimidine-2,4(1H,3H)-dione.
c
(2R,5S)-5-(4-Amino-2-oxopyrimidin-1(2H)-yl)-1,3-oxathiolane-2-carboxylic acid (2R,5S)-5-(cytosine-1-yl)-1,3-oxathiolane-2-carboxylic acid.
d
1-[(2R,3S,5SS)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine S-oxide.
e
1-[(2R,3R,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine S-oxide.
f
5-Methylpyrimidine-2,4(1H,3H)-dione.
g
1-[(2S,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]cytosine.
h
[1-(2-Deoxy-
 -d-ribofuranosyl)]thymine.
i
(2RS,5SR)1-[(2R,5S)-2-(Hydroxymethyl)-1,3-oxathiolan-5-yl]uracil.
j
2-Hydroxybenzoic acid.
k
3'-Chloro-3'-deoxythymidine.
*
The individual impurity limit is not included because these are processes/other impurities monitored individually in the drug substances.
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ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers, protected from light, and store between 2 and 30.
and 30.
• Labeling:
When more than one Dissolution test is given, the labeling states the Dissolution test used only if Test 1 is not used.
• USP Reference Standards 11
11
USP Lamivudine RS 
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USP Lamivudine Resolution Mixture B RS
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USP Zidovudine RS
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Behnam Davani, Ph.D., M.B.A.
Senior Scientific Liaison 1-301-816-8394 |
(SM12010) Monographs - Small Molecules 1 |
| 711 |
Margareth R.C. Marques, Ph.D.
Senior Scientific Liaison 1-301-816-8106 |
(GCDF2010) General Chapters - Dosage Forms |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 3633
Pharmacopeial Forum: Volume No. 35(2) Page 277