Aneurine tablets

The methods of assay for aneurine in complex galenicals have been developed from the original colorimetric or fluorimetric methods necessary for the small concentrations present in natural sources microbiological methods can also be used for small amounts. For tablets and injection solutions where the amounts are greater Adamson and Handisyde have shown that a gravimetric technique is more accurate. Titration in non-aqueous solvents is also applicable (see p. 792). 

For tablets Finely powder twenty tablets and weigh accurately an amount of powder expected to contain about 10 mg of aneurine into a 100-ml conical flask. Add exactly 5 ml of dilute hydrochloric acid and 10 ml of water, heat to boiling and boil gently for four minutes. Cooh add (x — 1) ml of N sodium hydroxide, transfer to a 100-ml graduated flask and dilute to 100 ml with water. (The value of x is the number of ml of N sodium hydroxide required to neutralise the hydrochloric acid in a control determination, after cooling.) Use 5 ml of this solution for a determination as described for simple solutions. 

When the tablets have a high aneurine content, they may be disintegrated and made up to volume in the graduated flask, since the volume error introduced by the insoluble matter is relatively small. The actual volume of the insoluble matter may be calculated, and hence its significance assessed, by the usual two-dilution method. 

Tablets of Aneurine Hydrochloride, B.P. The usual strength of this tablet is 3 mg and no difficulty is experienced in following either the fluorimetric or silicotungstic acid methods given above. It must be realised that the results of assay by the latter method may give rather different figures from the fluorimetric method.

Compound Tablets of Aneurine, B.P.C. Contain 1 mg each of aneurine hydrochloride and riboflavine and 15 mg of nicotinamide. 

Although the fluorimetric method given above is applicable to this preparation the method of Foster and Murfin described in more detail under Strong Compound Tablets of Aneurine can be applied, but for this simpler preparation the following technique may be used ... 

Elute the aneurine hydrochloride with 150 ml of 2N hydrochloric acid and measure the extinction of a 1-cm layer at about 246 m//. Calculate the weight of aneurine hydrochloride in a tablet of average weight using an E(1 per cent, 1 cm) of 41b at 246 m//. 

Capsules of Vitamins, B.P.C., are assayed for nicotinamide by the microbiological method given above under Nicotinic Acid. Compound Tablets of Aneurine, B.P.C.y and Strong Compound Tablets of Aneurine, B.P.C.y are assayed for nicotinamide by direct hydrolysis as given above under Nicotinamide using the equivalent of 20 and 15 tablets respectively. 

The riboflavine in Compound Tablets of Aneurine and Strong Compound Tablets of Aneurine can be determined by the above method. 

Strong Compound Tablets of Aneurine, B.P.C. These tablets contain 2 mg of pyridoxine hydrochloride together with nicotinamide (20 mg), aneurine hydrochloride (5 mg) and riboflavine (2 mg). The J8.P.C. prescribes a microbiological test for determination of the aneurine and pyridoxine, but the alginic acid separation method of Foster and Murfin is also applicable (see p. 461). 

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