Thiamine Hydrochloride Oral Solution
DEFINITION
Thiamine Hydrochloride Oral Solution contains NLT 95.0% and NMT 135.0% of the labeled quantity of thiamine hydrochloride (C12H17ClN4OS·HCl).
IDENTIFICATION
•  A.
Sample solution:  Dilute a portion of Oral Solution with water to a concentration of 10 mg/mL of thiamine hydrochloride.
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.
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 about 50 µg/mL.
Sample stock solution:  Equivalent to 500 µg/mL of thiamine hydrochloride 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 hydrochloride of about 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 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 hydrochloride (C12H17ClN4OS·HCl) in the portion of Oral Solution taken:
Result = (RU/RS) × (CS/CU) × 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 hydrochloride in the Sample stock solution (µg/mL)
Acceptance criteria:  95.0%–135.0%
OTHER COMPONENTS
•  Alcohol Determination, Method II 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
USP Thiamine Hydrochloride RS Click to View Structure
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 4836
Pharmacopeial Forum: Volume No. 28(2) Page 379