Dexpanthenol (Provitamin B5)

Dexpanthenol is the alcohol analogue of pantothenic acid: the carboxyl group of vitamin B5 is reduced to a primary alcohol, giving (2R)-2,4-dihydroxy-N-(3-hydroxypropyl)-3,3-dimethylbutanamide, CAS 81-13-0, C9H19NO4, molecular weight 205.25. It is a provitamin, converted in the body to pantothenic acid, which is the building block of coenzyme A and of acyl carrier protein. Only the D-enantiomer carries that vitamin activity, and the specification that proves it is the specific optical rotation: +29.0 to +32.0 degrees under Ph. Eur./BP, +29.0 to +31.5 degrees under USP. Assay is 98.0 to 102.0 per cent on the anhydrous basis (USP) or 98.0 to 101.0 per cent (Ph. Eur./BP), with water not more than 1.0 per cent, 3-aminopropanol not more than 1.0 per cent, residue on ignition not more than 0.1 per cent and refractive index 1.495 to 1.502 at 20 degrees C. The form question matters, because pharmacopoeial dexpanthenol is not a powder. It is a colourless to slightly yellowish, clear, viscous, hygroscopic liquid of about 1.20 g/mL at 20 degrees C, which is why it is drummed rather than bagged. Three routes exist if a dry blend is what you need, and they are not interchangeable. Calcium D-pantothenate is the usual free-flowing vitamin B5 powder for tablets and premixes and is stocked as a separate item. Panthenol adsorbed or spray-dried onto a carrier such as maltodextrin or silica gives a powder but is no longer an unmixed substance, which changes both the assay basis and the tariff line. DL-panthenol, CAS 16485-10-2, is a genuine white crystalline powder melting at 66 to 69 degrees C, but it is the racemate: only half of it is the active D-form, so it is a cosmetic raw material and should not be used where vitamin B5 activity is being declared. Thovek will quote whichever of these actually fits the formulation rather than shipping a liquid against a powder line. Dexpanthenol is very soluble in water and freely soluble in ethanol (96 per cent), and it is stable in neutral solution but hydrolyses back to pantothenic acid and 3-aminopropanol under acid or alkaline conditions, so formulations should be held near neutral pH and the material stored in airtight containers protected from heat, light and moisture. Its regulatory footing is well established: it is a permitted source of vitamin B5 in EU food supplements under Annex II of Directive 2002/46/EC, it carries the cosmetic INCI name Panthenol, and D-panthenol is authorised in the EU as a nutritional feed additive (3a842) for all animal species. The material is manufactured synthetically with no animal-derived input, so it is vegan and vegetarian suitable and free of the major food allergens. Supply is against USP, Ph. Eur./BP or IP specification with a batch certificate of analysis covering assay, optical rotation, refractive index, water, 3-aminopropanol and heavy metals, plus MSDS and allergen, vegan and non-GMO declarations.