Vitamin B1 (Thiamine Mononitrate)

Thiamine mononitrate, also named thiamine nitrate, is the nitrate salt of thiamine (vitamin B1), CAS 532-43-4, molecular formula C12H17N5O4S, molecular weight 327.36. Both USP and Ph. Eur./BP require 98.0-102.0% assay calculated on the dried basis, equivalent to a theoretical thiamine content of about 81.1% by weight, the highest of the two commercial thiamine salts. It presents as a white to almost white crystalline powder or small colourless crystals, sparingly soluble in water, freely soluble in boiling water and only slightly soluble in ethanol (96 per cent) and methanol. A 10 g/L aqueous solution is close to neutral, with the Ph. Eur. limit at pH 6.8 to 7.6. The practical difference from the hydrochloride is moisture behaviour. Thiamine mononitrate takes up very little water, so it holds assay and flow far better in dry systems than the hygroscopic hydrochloride, and its near-neutral solution pH avoids the local acidity that the hydrochloride can introduce. That makes it the standard vitamin B1 source for wheat flour, maize meal and rice fortification premixes, for multivitamin and mineral premixes containing hygroscopic partners such as choline chloride, for direct-compression tablets and dry-blended sachets, and for extruded, baked and retorted foods. It is affirmed GRAS under 21 CFR 184.1878, is listed in Annex II of Directive 2002/46/EC as a permitted vitamin B1 source for EU food supplements, and is authorised as feed additive 3a821. Standard supply is a fine crystalline powder; a coarse, low-dust grade is available where premix blending and gravimetric dosing favour larger particles. Each lot is released against a certificate of analysis reporting identification, assay, loss on drying, residue on ignition and sulphated ash, chloride, heavy metals, residual solvents and microbiological limits, with MSDS, non-GMO, allergen, BSE/TSE and halal or kosher statements supplied as required for the destination market.