Thiamine Tablets

Vitamin B₁.

Thiamine Tablets contain Thiamine Hydrochloride.

The tablets comply with the requirements stated under Tablets and with the following requirements.

92.5  to 107.5% of the stated amount.

A.  Carry out the method for thin-layer chromatography, Appendix III A, using cellulose F₂₅₄ as the coating substance and a mixture of 60  volumes of butan-1-ol, 25  volumes of water and 15  volumes of glacial acetic acid as the mobile phase. Apply separately to the plate 2 µl of each of the following solutions. For solution (1) shake a quantity of the powdered tablets containing 20  mg of Thiamine Hydrochloride with 20  ml of water and filter. Solution (2) contains 0.1% w/v of thiamine mononitrate BPCRS. After removal of the plate, allow it to dry in air, heat at 105° for 30  minutes, 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 and examine under ultraviolet light (365  nm). The principal spot in the chromatogram obtained with solution (1) corresponds 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 1m acetic acid, filter, add 1.6  ml of 1m sodium hydroxide, heat in a water bath for 30  minutes and cool. Add 5  ml of 5m 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 1m sodium hydroxide and 0.2  g of sodium sulphite in place of the 1.6  ml of 1m sodium hydroxide; not more than a slight fluorescence is produced.

Weigh and powder 20  tablets. Carry out the Assay described under Thiamine Injection using the following solutions. Solution (1) contains 0.006% w/v of thiamine mononitrate BPCRS in 0.005m hydrochloric acid. Prepare solution (2) in the following manner. For tablets containing less than 10  mg of thiamine hydrochloride, 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, 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.

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.