Thiamine Mononitrate Oral Solution
DEFINITION
Thiamine Mononitrate Oral Solution contains NLT 95.0% and NMT 115.0% of the labeled amount of thiamine mononitrate (C12H17N5O4S).
IDENTIFICATION
• A.
Sample solution:
Dilute a portion of Oral Solution with water to a concentration of 10 mg/mL of thiamine mononitrate.
Analysis:
To 0.5 mL of the Sample solution add 5 mL of 0.5 N sodium hydroxide, then add 0.5 mL of potassium ferricyanide TS and 5 mL of isobutyl alcohol. Shake the mixture vigorously for 2 min, and allow the liquid layers to separate. Illuminate from above by a vertical beam of UV light and observe the air–liquid meniscus at a right angle to this beam.
Acceptance criteria:
The air–liquid meniscus shows a vivid blue fluorescence, which disappears when the mixture is slightly acidified, but reappears when it is again made alkaline.
• B.
Sample:
5 mL of Oral Solution
Analysis:
Add 2 mL of sulfuric acid to the Sample, cool, and superimpose 2 mL of ferrous sulfate TS.
Acceptance criteria:
A brown ring is produced at the junction of the two liquids.
ASSAY
• Procedure
Mobile phase:
Methanol and 0.04 M aqueous monobasic potassium phosphate (45:55)
Internal standard solution:
100 µg/mL of methylparaben in Mobile phase
Standard stock solution:
500 µg/mL of USP Thiamine Hydrochloride RS in Mobile phase
Standard solution:
Dilute a mixture of equal volumes of the Standard stock solution and Internal standard solution with Mobile phase to obtain a concentration of USP Thiamine Hydrochloride RS of 50 µg/mL.
Sample stock solution:
Equivalent to 500 µg/mL of thiamine mononitrate in Mobile phase from an accurately measured volume of Oral Solution
Sample solution:
Dilute a mixture of equal volumes of the Sample stock solution and Internal standard solution with Mobile phase to obtain a concentration of thiamine mononitrate of 50 µg/mL.
Chromatographic system
Mode:
LC
Detector:
UV 254 nm
Column:
3.9-mm × 30-cm; packing L1
Flow rate:
1 mL/min
Injection size:
25 µL
System suitability
Sample:
Standard solution
[Note—The relative retention times for thiamine and methylparaben are about 0.35 and 1.0, respectively. ]
Suitability requirements
Resolution:
NLT 6.0 between the thiamine and methylparaben
Relative standard deviation:
NMT 2.0%
Analysis
Samples:
Standard solution and Sample solution
Calculate the percentage of the labeled amount of thiamine mononitrate (C12H17N5O4S) in the portion of Oral Solution taken:
Result = (RU/RS) × (CS/CU) × (Mr1/Mr2) × 100
| RU | = | = peak area ratio of thiamine to methylparaben from the Sample solution |
| RS | = | = peak area ratio of thiamine to methylparaben from the Standard solution |
| CS | = | = concentration of USP Thiamine Hydrochloride RS in the Standard stock solution (µg/mL) |
| CU | = | = nominal concentration of thiamine mononitrate in the Sample stock solution (µg/mL) |
| Mr1 | = | = molecular weight of thiamine mononitrate, 327.36 |
| Mr2 | = | = molecular weight of thiamine hydrochloride, 337.27 |
Acceptance criteria:
95.0%–115.0%
OTHER COMPONENTS
• Alcohol Determination, Method II 
611
:
90.0%–110.0% of the labeled quantity of C2H5OH, using acetone as the internal standard
611:
90.0%–110.0% of the labeled quantity of C2H5OH, using acetone as the internal standard
ADDITIONAL REQUIREMENTS
• Packaging and Storage:
Preserve in tight, light-resistant containers.
• USP Reference Standards 11
11
USP Thiamine Hydrochloride RS 
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Auxiliary Information—
Please check for your question in the FAQs before contacting USP.
| Topic/Question | Contact | Expert Committee |
|---|---|---|
| Monograph | Natalia Davydova
Scientific Liaison 1-301-816-8328 |
(DS2010) Monographs - Dietary Supplements |
| Reference Standards | RS Technical Services 1-301-816-8129 rstech@usp.org |
USP35–NF30 Page 4839
Pharmacopeial Forum: Volume No. 28(2) Page 381