Riluzole Tablets
DEFINITION
Riluzole Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of riluzole (C8H5F3N2OS).
IDENTIFICATION
• A. Ultraviolet Absorption 
197U
:
The spectrum of the Sample solution corresponds to that of the Standard solution, as obtained in the test for Dissolution.
197U:
The spectrum of the Sample solution corresponds to that of the Standard solution, as obtained in the test for Dissolution.
• 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 stock solution:
Weigh and finely powder NLT 20 Tablets. Transfer a portion of the powder, equivalent to 50 mg of riluzole, to a 100-mL volumetric flask, add 80 mL of Mobile phase, sonicate for about 10 min, and stir for another 10 min. Dilute with Mobile phase to volume.
Sample solution:
0.05 mg/mL of riluzole in Mobile phase, prepared from Sample stock solution. Pass this solution through a PVDF (or equivalent) filter of 0.45-µm pore size, and discard the first 5 mL of filtrate. Use the filtrate for analysis.
Chromatographic system
Mode:
LC
Detector:
UV 221 nm
Column:
4.6-mm × 15-cm; 5-µm packing L1
Flow rate:
1 mL/min
Injection size:
20 µL
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 Tablets 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 | = | = nominal concentration of riluzole in the Sample solution (mg/mL) |
Acceptance criteria:
90.0%–110.0%
PERFORMANCE TESTS
• Dissolution 711
711
Medium:
0.1 N hydrochloric acid; 900 mL, deaerated
Apparatus 2:
50 rpm
Time:
30 min
Standard solution:
0.05 mg/mL of USP Riluzole RS in Medium
Sample solution:
Pass a portion of the solution under test through a suitable filter of 0.45-µm pore size.
Detector:
UV 254 nm
Blank:
Medium
Cell:
0.5 cm
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of riluzole taken:
Result = (AU/AS) × (CS × V/L) × 100
| AU | = | = absorbance of the Sample solution |
| AS | = | = absorbance of the Standard solution |
| CS | = | = concentration of USP Riluzole RS in the Standard solution (mg/mL) |
| V | = | = volume of Medium, 900 mL |
| L | = | = label claim (mg/Tablet) |
Tolerances:
NLT 80% (Q) of the labeled amount of C8H5F3N2OS is dissolved.
• Uniformity of Dosage Units 905:
Meet the requirements
905:
Meet the requirements
IMPURITIES
Organic Impurities
• Procedure
Mobile phase and Chromatographic system:
Proceed as directed in the Assay.
Standard solution:
2.5 µg/mL of USP Riluzole RS in Mobile phase, prepared from the Standard solution under the Assay
System suitability solution:
500 µg/mL of USP Riluzole RS and 0.5 µg/mL of USP Riluzole Related Compound A RS in Mobile phase
Sample solution:
0.5 mg/mL, Sample stock solution
System suitability
Samples:
Standard solution and System suitability solution
Suitability requirements
Resolution:
NLT 1.5 between riluzole and riluzole related compound A, System suitability solution
Tailing factor:
NMT 2.0, Standard solution
Relative standard deviation:
NMT 2.0%, Standard solution
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of each impurity in the portion of Tablets 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 (µg/mL) |
| CU | = | = nominal concentration of riluzole in the Sample solution (µg/mL) |
Acceptance criteria
Individual impurities:
NMT 0.2%
Total impurities:
NMT 1.0%
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in well-closed, light-resistant containers, and store at controlled room temperature.
• 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 |
| 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 4559
Pharmacopeial Forum: Volume No. 35(5) Page 1174