Riluzole
C8H5F3N2OS 234.20
2-Benzothiazolamine, 6-(trifluoromethoxy)-;
2-Amino-6-(trifluoromethoxy)benzothiazole
[1744-22-5].
(ril' ue zole).
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C8H5F3N2OS 234.20
2-Benzothiazolamine, 6-(trifluoromethoxy)-;
2-Amino-6-(trifluoromethoxy)benzothiazole
[1744-22-5].DEFINITION
Riluzole contains NLT 98.0% and NMT 102.0% of the labeled amount of C8H5F3N2OS, calculated on the anhydrous 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
Mobile phase:
Acetonitrile and water (9:11)
Standard solution:
0.05 mg/mL of USP Riluzole RS in Mobile phase
Sample solution:
0.05 mg/mL of Riluzole in Mobile phase
Chromatographic system
Mode:
LC
Detector:
UV 221 nm
Column:
4.6-mm × 15-cm; 5-µm packing L1
Flow rate:
2.0 mL/min
Injection size:
20 µL. [Note—Monitor for 3 times the retention time of riluzole. ]
System suitability
Sample:
Standard solution
Suitability requirements
Tailing factor:
NMT 2.0
Relative standard deviation:
NMT 2.0%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of C8H5F3N2OS in the portion of Riluzole taken:
Result = (rU/rS) × (CS/CU) × 100
| rU | = | = peak response from the Sample solution |
| rS | = | = peak response from the Standard solution |
| CS | = | = concentration of USP Riluzole RS in the Standard solution (mg/mL) |
| CU | = | = concentration of Riluzole in the Sample solution (mg/mL) |
Acceptance criteria:
98.0%–102.0% on the anhydrous basis
IMPURITIES
Inorganic Impurities
• Residue on Ignition 
281
:
NMT 0.1%, a 1.5-g of sample used
281:
NMT 0.1%, a 1.5-g of sample used
• Heavy Metals, Method II 231:
NMT 20 ppm
231:
NMT 20 ppm
Organic Impurities
• Procedure
Mobile phase:
Proceed as directed in the Assay.
System suitability solution:
500 µg/mL of USP Riluzole RS and 0.5 µg/mL USP Riluzole Related Compound A RS in Mobile phase
Standard solution:
0.5 µg/mL of USP Riluzole RS in Mobile phase
Sample solution:
500 µg/mL of Riluzole in Mobile phase
Chromatographic system:
Proceed as directed in the Assay, and use an injection volume of 100 µL.
[Note—Monitor for 11 times the retention time of riluzole. ]
System suitability
Samples:
System suitability solution and Standard solution
Suitability requirements
Tailing factor:
NMT 2.0, Standard solution
Resolution:
NLT 1.5 between Riluzole and riluzole related compound A, System suitability solution
Relative standard deviation:
NMT 2.0%, Standard solution
Analysis
Samples:
Standard solution and Sample solution
Identify the impurities using the relative retention times shown in Impurity Table 1. Calculate the percentage of each impurity in the portion of Riluzole taken:
Result = (rU/rS) × (CS/CU) × (1/F) × 100
| rU | = | = peak response of the impurity from the Sample solution |
| rS | = | = peak response of Riluzole from the Standard solution |
| CS | = | = concentration of USP Riluzole RS in the Standard solution (µg/mL) |
| CU | = | = concentration of Riluzole in the Sample solution (µg/mL) |
| F | = | = relative response factor relative to riluzole |
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 (%) |
|---|---|---|---|
| Riluzole | 1.0 | — | — |
| Riluzole related compound Aa | 1.3 | 0.16 | 0.1 |
| Bromoriluzoleb | 1.9 | 0.54 | 0.2 |
| Dibromotrifluoromethoxyanilinec | 7.4 | 0.28 | 0.1 |
| Any unspecified impurity | — | 1.0 | 0.1 |
|
a
4-(Trifluoromethoxy)aniline.
b
4-Bromo-6-(trifluoromethoxy)benzothiazol-2-amine.
c
2,6-Dibromo-4-(trifluoromethoxy)aniline.
|
|||
SPECIFIC TESTS
• Water Determination, Method I 921:
NMT 0.5%
921:
NMT 0.5%
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed containers
• USP Reference Standards 11
11
USP Riluzole RS 
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USP Riluzole Related Compound A RS
4-Trifluoromethoxyphenylamine; 4-trifluoromethoxyanaline.
C7H6F3NO 177.12
4-Trifluoromethoxyphenylamine; 4-trifluoromethoxyanaline.
C7H6F3NO 177.12
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 4558
Pharmacopeial Forum: Volume No. 35(5) Page 1173