Action and use
Vitamin B1.
Definition
Thiamine Tablets contain Thiamine Hydrochloride.
The tablets comply with the requirements stated under Tablets and with the following requirements.
Content of thiamine hydrochloride, C12H17ClN4OS,HCl
92.5 to 107.5% of the stated amount.
Identification
(1) Shake a quantity of the powdered tablets containing 20 mg of Thiamine Hydrochloride with 20 mL of
water and filter.
chromatographic conditions
(b) Use the mobile phase as described below.
(c) Apply 2 µL of each solution.
(d) Develop the plate to 15 cm.
(e) After removal of the plate, allow it to dry in air, heat at 105° for 30 minutes and spray with a mixture of equal volumes of a 0.3% w/v solution of
potassium hexacyanoferrate(
III) and a 10% w/v solution of
sodium hydroxide. Examine under
ultraviolet light (
365 nm).
mobile phase
15 volumes of glacial acetic acid, 25 volumes of water and 60 volumes of butan-1-ol.
confirmation
The principal spot in the chromatogram obtained with solution (1) corresponds in position and colour to that in the chromatogram obtained with solution (2).
B. Dissolve a quantity of the powdered tablets containing 20 mg of Thiamine Hydrochloride as completely as possible in 10 mL of
water and 2 mL of 1
m acetic acid, filter, add 1.6 mL of 1
m sodium hydroxide, heat in a water bath for 30 minutes and cool. Add 5 mL of 5
m sodium hydroxide, 10 mL of
dilute potassium hexacyanoferrate(
III)
solution and 10 mL of
butan-1-ol and shake vigorously for 2 minutes. The alcohol layer shows an intense light blue fluorescence on exposure to ultraviolet light. Repeat the test but adding 0.9 mL of 1
m sodium hydroxide and 0.2 g of
sodium sulfite in place of the 1.6 mL of 1
m sodium hydroxide; not more than a slight fluorescence is produced.
Assay
Weigh and powder 20 tablets. Carry out the method for liquid chromatography, Appendix III D, using the following solutions.
For tablets containing less than 10 mg of Thiamine Hydrochloride:
(1) Add 5 mL of
0.1m hydrochloric acid and 50 mL of
water to a quantity of the powdered tablets containing 6 mg of Thiamine Hydrochloride, shake for 20 minutes, dilute to 100 mL with
water and filter.
For tablets containing 10 mg or more of Thiamine Hydrochloride:
(1) Add 50 mL of
0.1m hydrochloric acid and 500 mL of
water to a quantity of the powdered tablets containing 60 mg of Thiamine Hydrochloride, shake for 20 minutes, dilute to 1000 mL with
water and filter.
chromatographic conditions
(b) Use isocratic elution and the mobile phase described below.
(c) Use a flow rate of 2 mL per minute.
(d) Use an ambient column temperature.
(e) Use a detection wavelength of 244 nm.
(f) Inject 20 µL of each solution.
mobile phase
Dissolve 1 g of sodium heptane sulfonate in a mixture of 180 mL of methanol and 10 mL of triethylamine, diluting to 1000 mL with water and adjusting the pH to 3.2 with orthophosphoric acid.
determination of content
Calculate the content of C12H17ClN4OS,HCl using the declared content of C12H17N5O4S in thiamine mononitrate BPCRS. Each mg of C12H17N5O4S is equivalent to 1.030 mg of C12H17ClN4OS,HCl.
Storage
Thiamine Tablets should be kept free from contact with metal and protected from light.
When vitamin B1 tablets are prescribed or demanded, Thiamine Tablets shall be dispensed or supplied.