Abacavir Sulfate
(C14H18N6O)2·H2SO4 670.74
2-Cyclopentene-1-methanol, 4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-, (1S-cis)-, sulfate (salt) (2:1);
(1S,4R)-4-[2-Amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclopentene-1-methanol sulfate (salt) (2:1)
[188062-50-2].
(a bak' a vir sul' fate).
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(C14H18N6O)2·H2SO4 670.74
2-Cyclopentene-1-methanol, 4-[2-amino-6-(cyclopropylamino)-9H-purin-9-yl]-, (1S-cis)-, sulfate (salt) (2:1);
(1S,4R)-4-[2-Amino-6-(cyclopropylamino)-9H-purin-9-yl]-2-cyclopentene-1-methanol sulfate (salt) (2:1)
[188062-50-2].DEFINITION
Abacavir Sulfate contains NLT 97.0% and NMT 102.0% of (C14H18N6O)2·H2SO4, 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, obtained as directed in the test for Organic Impurities, Procedure 2.
• C. Identification Tests—General, Sulfate 
191
191
Sample solution:
5 mg/mL
ASSAY
• Procedure
Mobile phase:
Acetonitrile, phosphoric acid, and water (20:1:180)
Standard solution:
0.04 mg/mL of USP Abacavir Sulfate RS in water
Sample solution:
0.04 mg/mL of Abacavir Sulfate in water
Chromatographic system
Mode:
LC
Detector:
UV 254 nm
Column:
4.6-mm × 5-cm; 5-µm packing L1
Column temperature:
30
Flow rate:
1 mL/min
Injection size:
20 µL
System suitability
Sample:
Standard solution
Suitability requirements
Relative standard deviation:
NMT 1.5%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of (C14H18N6O)2·H2SO4 in the portion of Abacavir Sulfate taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak area of abacavir from the Sample solution |
| rS | = | = peak area of abacavir from the Standard solution |
| CS | = | = concentration of USP Abacavir Sulfate RS in the Standard solution (mg/mL) |
| CU | = | = concentration of Abacavir Sulfate in the Sample solution (mg/mL) |
Acceptance criteria:
97.0%–102.0% on the anhydrous and solvent-free basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition 281:
NMT 0.2%
281:
NMT 0.2%
Organic Impurities
• Procedure 1: Related Compounds
Solution A:
Trifluoroacetic acid and water (0.05:99.95)
Solution B:
Methanol and water (17:3)
Mobile phase:
See the gradient table below.
| Time (min) |
Solution A
(%) |
Solution B
(%) |
|---|---|---|
| 0 | 95 | 5 |
| 20 | 70 | 30 |
| 35 | 10 | 90 |
| 35.1 | 95 | 5 |
| 50 | 95 | 5 |
System suitability solution:
0.25 mg/mL of USP Abacavir Related Compounds Mixture RS in water
Sample solution:
0.25 mg/mL of Abacavir Sulfate in water
Chromatographic system
Mode:
LC
Detector:
UV 254 nm
Column:
3.9-mm × 15-cm; 5-µm packing L1
Column temperature:
30
Flow rate:
1 mL/min
Injection size:
20 µL
System suitability
Sample:
System suitability solution
Suitability requirements
Resolution:
NLT 1.5 between abacavir and trans-abacavir
Analysis
Sample:
Sample solution
Calculate the percentage of each impurity in the portion of Abacavir Sulfate taken:
Result = (rU/rT) × 100
| rU | = | = peak area of each impurity from the Sample solution |
| rT | = | = sum of the areas of all the peaks from the Sample solution |
Acceptance criteria
Individual impurities:
See Impurity Table 1.
Total impurities:
NMT 0.8%
Impurity Table 1
| Name | Relative Retention Time |
Acceptance Criteria, NMT (%) |
|
|---|---|---|---|
| Descyclopropyl abacavira | 0.65 | 0.2 | |
| Abacavir | 1.00 | — | |
| trans-Abacavirb | 1.04 | 0.2 | |
| O-Pyrimidine derivative abacavirc | 1.33 | 0.2 | |
| t-Butyl derivative abacavird | 1.67 | 0.2 | |
| Any unspecified impurity | — | 0.1 | |
|
a
[(1S,4R)-4-(2,6-Diamino-9H-purin-9-yl)cyclopent-2-enyl]methanol.
b
{(1R,4R)-4-[2-Amino-6-(cyclopropylamino)-9H-purin-9-yl]-cyclopent-2-enyl}methanol.
c
N6-Cyclopropyl-9-{(1R,4S)-4-[(2,5-diamino-6-chloropyrimidin-4-yloxy)methyl]cyclopent-2-enyl}-9H-purine-2,6-diamine.
d
9-[(1R,4S)-4-(tert-Butoxymethyl)cyclopent-2-enyl]-N6-cyclopropyl-9H-purine-2,6-diamine.
|
|||
• Procedure 2: Enantiomeric Purity
Solution A:
Heptane, 2-propanol, and diethylamine (850:150:1).
Solution B:
Heptane and 2-propanol (1:1)
Mobile phase:
See the gradient table below.
| Time (min) |
Solution A
(%) |
Solution B
(%) |
Flow Rate (mL/min) |
|---|---|---|---|
| 0 | 100 | 0 | 1.0 |
| 25 | 100 | 0 | 1.0 |
| 27 | 0 | 100 | 0.8 |
| 37 | 0 | 100 | 0.8 |
| 39 | 100 | 0 | 1.0 |
| 55 | 100 | 0 | 1.0 |
Diluent:
Methanol and trifluoroacetic acid (200:1)
System suitability solution:
Transfer a quantity of USP Abacavir Stereoisomers Mixture RS to a suitable volumetric flask, add a volume of Diluent equivalent to 30% of the final volume, and sonicate until the solid is fully dissolved. Add a volume of 2-propanol equivalent to about 30% of the final volume, mix, and dilute with heptane to volume to obtain 0.4 mg/mL of USP Abacavir Stereoisomers Mixture RS.
Sample solution:
Transfer 4 mg of Abacavir Sulfate to a 10-mL volumetric flask. Add 3 mL of Diluent, and sonicate until the solid is fully dissolved. Add 3 mL of 2-propanol, mix, and dilute with heptane to volume.
Chromatographic system
Mode:
LC
Detector:
UV 286 nm
Column:
4.6-mm × 25-cm; 10-µm packing L51
Column temperature:
30
Injection size:
20 µL
System suitability
[Note—The relative retention times for trans-abacavir, abacavir enantiomer, and abacavir are 0.8, 0.9, and 1.0, respectively. ]
Sample:
System suitability solution
Suitability requirements
Resolution:
NLT 1.0 between trans-abacavir and abacavir enantiomer; NLT 1.5 between abacavir enantiomer and abacavir
Analysis
Sample:
Sample solution
Calculate the percentage of abacavir enantiomer in the portion of Abacavir Sulfate taken:
Result = (rU/rT) × 100
| rU | = | = peak area of abacavir enantiomer from the Sample solution |
| rT | = | = total peak areas of abacavir and abacavir enantiomer from the Sample solution |
Acceptance criteria
Individual impurities:
NMT 0.3% of abacavir enantiomer
SPECIFIC TESTS
• Water Determination, Method Ic 921:
NMT 0.5%
921:
NMT 0.5%
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers. Store at room temperature.
• USP Reference Standards 11
11
USP Abacavir Sulfate RS 
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USP Abacavir Stereoisomers Mixture RS
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A mixture of abacavir sulfate, abacavir enantiomer, and trans-abacavir.
USP Abacavir Related Compounds Mixture RS
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A mixture of abacavir glutarate, O-pyrimidine derivative abacavir, descyclopropyl abacavir, trans-abacavir, and t-butyl derivative abacavir.
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 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2021
Pharmacopeial Forum: Volume No. 36(3) Page 651