Amphetamine Sulfate
(C9H13N)2·H2SO4 368.49
Benzeneethanamine,
-methyl-, sulfate (2:1), (±)-;
(±)--Methylphenethylamine sulfate (2:1)
[60-13-9].
(am fet' a meen sul' fate).
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(C9H13N)2·H2SO4 368.49
Benzeneethanamine,
-methyl-, sulfate (2:1), (±)-;
(±)-
-Methylphenethylamine sulfate (2:1)
[60-13-9].DEFINITION
Amphetamine Sulfate contains NLT 98.0% and NMT 102.0% of (C9H13N)2·H2SO4 on the dried basis.
IDENTIFICATION
• B.
The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.
ASSAY
• Procedure
Solution A:
Add 5.0 mL of trifluoroacetic acid to 900 mL of water, adjust with ammonium hydroxide to a pH of 2.2 ± 0.1, and add 100 mL of acetonitrile.
Solution B:
Use degassed acetonitrile.
Mobile phase:
See the gradient table below.
| Time (min) |
Solution A (%) |
Solution B (%) |
|---|---|---|
| 0 | 100 | 0 |
| 15 | 65 | 35 |
| 20 | 0 | 100 |
| 22 | 0 | 100 |
| 23 | 100 | 0 |
| 30 | 100 | 0 |
Standard solution:
2.0 mg/mL of USP Dextroamphetamine Sulfate RS in Solution A
System suitability solution:
Transfer 40 mL of the Standard solution to a 50-mL volumetric flask. Using a microliter syringe, add 1 µL each of USP Dextroamphetamine Related Compound A RS and USP Dextroamphetamine Related Compound B RS. Dilute with Standard solution to volume, and mix.
Sample solution:
2.0 mg/mL of Amphetamine Sulfate in Solution A
Chromatographic system
Mode:
LC
Detector:
UV 257 nm
Column:
4.6-mm × 15-cm; 5-µm packing L1
Column temperature:
40
Flow rate:
1.5 mL/min
Injection size:
20 µL
System suitability
Samples:
Standard solution and System suitability solution
[Note—Identify the peaks by the relative retention times in Impurity Table 1 under Organic Impurities. Amphetamine and dextroamphetamine have exactly the same retention time. ]
Suitability requirements
Resolution:
NLT 3.0 between dextroamphetamine related compound A and dextroamphetamine related compound B, System suitability solution
Tailing factor:
NMT 3.0, Standard solution
Relative standard deviation:
NMT 2.0%, Standard solution
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of (C9H13N)2·H2SO4 in the portion of Amphetamine Sulfate taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response for amphetamine sulfate from the Sample solution |
| rS | = | = peak response for dextroamphetamine sulfate from the Standard solution |
| CS | = | = concentration of USP Dextroamphetamine Sulfate RS in the Standard solution (mg/mL) |
| CU | = | = concentration of Amphetamine Sulfate in the Sample solution (mg/mL) |
Acceptance criteria:
98.0%–102.0% on the dried basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition 
281
:
NMT 0.2%
281:
NMT 0.2%
Organic Impurities
• Procedure
Solution A, Solution B, Mobile phase, System suitability solution, Standard solution, Sample solution, Chromatographic system, and System suitability:
Proceed as directed in the Assay.
Analysis
Samples:
Standard solution and Sample solution
[Note—Identify the impurities by the relative retention times in Impurity Table 1. ]
Calculate the percentage of each impurity in the portion of Amphetamine Sulfate taken:
Result = (rU/rS) × (CS/CU) × (1/F) × 100
| rU | = | = peak response for each impurity from the Sample solution |
| rS | = | = peak response for dextroamphetamine from the Standard solution |
| CS | = | = concentration of USP Dextroamphetamine Sulfate RS in the Standard solution (mg/mL) |
| CU | = | = concentration of Amphetamine Sulfate in the Sample solution (mg/mL) |
| F | = | = relative response factor (see Impurity Table 1) |
Acceptance criteria
Individual impurities:
See Impurity Table 1.
Total impurities:
NMT 1.0%
Impurity Table 1
| Name | Relative Retention Time |
Relative Response Factor |
Acceptance Criteria, NMT (%) |
|---|---|---|---|
| Cathinone | 0.81 | 55.6 | 0.25 |
| Amphetamine | 1.0 | 1.0 | — |
| Benzaldehyde | 1.73 | 105.3 | 0.25 |
| Dextroamphetamine related compound A | 1.88 | 1.5 | 0.25 |
| Dextroamphetamine related compound B | 2.05 | 1.8 | 0.25 |
| Individual unspecified impurity | — | 1.0 | 0.1 |
SPECIFIC TESTS
• Loss on Drying 731:
Dry a sample at 105 for 2 h: it loses NMT 1.0% of its weight.
731:
Dry a sample at 105 for 2 h: it loses NMT 1.0% of its weight.
• Dextroamphetamine:
A solution (20 mg/mL) is optically inactive.
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers.
• USP Reference Standards 11
11
USP Dextroamphetamine Sulfate RS 
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USP Dextroamphetamine Related Compound A RS
1-Phenyl-2-propanol.
C9H12O 136.20[CAS-14898-87-4].
1-Phenyl-2-propanol.
C9H12O 136.20
[CAS-14898-87-4].
USP Dextroamphetamine Related Compound B RS
Phenyl acetone.
C9H10O 134.18[CAS-103-79-7].
Phenyl acetone.
C9H10O 134.18
[CAS-103-79-7].
Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Ravi Ravichandran, Ph.D.
Principal Scientific Liaison 1-301-816-8330 |
(SM42010) Monographs - Small Molecules 4 |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 2204
Pharmacopeial Forum: Volume No. 36(1) Page 68