Pyridoxine Hydrochloride (Vitamin B6)

Grades and forms

Pyridoxine hydrochloride is the hydrochloride salt of pyridoxine and the most widely used source of vitamin B6 in food supplements. By molar mass, it contains about 82.3 % pyridoxine. It is a crystalline solid that formulators buy mainly as a powder for blending, encapsulation and compression. For a wider view of the vitamer forms, see the vitamin B6 guide.

Manufacturers typically choose between three physical presentations:

• Crystalline powder for capsules, powders and liquid formats where the material is dissolved.
• Fine or milled powder where blend uniformity at low inclusion levels matters.
• Diluted premixes or triturations on a carrier, used when a few milligrams must be spread evenly through a large batch.

The choice depends on the dose per unit, the batch size and the mixing equipment. Pharmacopoeia-grade and food-grade material are both used in supplements. Ask for the grade you need in the quote form. SoleChem sends the specification sheet and certificate of analysis with its quote. These state the assay, particle size and the other parameters your quality team will check.

EU regulatory status

Pyridoxine hydrochloride is listed in Annex II of Directive 2002/46/EC as a permitted source of vitamin B6 in food supplements. Vitamin B6 itself appears in Annex I of the same Directive. The form is also listed for the addition of vitamins to other foods under Regulation (EC) No 1925/2006. The full list of permitted sources is explained in the guide to permitted vitamin and mineral forms.

The EU has not set harmonised maximum amounts of vitamin B6 in food supplements. Member states apply their own maximum levels, and these differ. Check the rules of each target market in the guide to maximum levels by EU country.

On the label, vitamin B6 is declared in milligrams under Article 8 and Annex I of Directive 2002/46/EC, and the general labelling rules of Regulation (EU) No 1169/2011 also apply. See labelling a food supplement in the EU for the format. Authorised health claims for vitamin B6 are in the EU Register of nutrition and health claims. The health-claims guide explains how to use them.

Formulation notes

The label-claim arithmetic starts from the molar masses. Pyridoxine (C8H11NO3) has a molar mass of about 169.18 g/mol. The hydrochloride salt is 205.64 g/mol, so pyridoxine is 82.3 % of the salt by mass.

These figures assume 100 % assay. Correct them for the assay on the certificate of analysis and add any overage your stability data supports. The overage calculator handles both steps.

In tablets and capsules, the dose is small relative to the fill or tablet mass. Blend uniformity is the main concern: use a premix or geometric dilution rather than adding the crystals directly to a large batch. In multivitamin and B-complex blends it sits alongside thiamine hydrochloride and riboflavin.

Pyridoxine hydrochloride is readily soluble in water and gives an acidic solution. This suits drink powders and effervescent tablets. In effervescent formats, its acidity adds to the acid side of the couple, so keep it dry until use. The material is sensitive to light, particularly in solution. Use light-protective packaging for liquids and transparent capsules. It has a bitter taste that may need masking in chewables, gummies and unflavoured powders.

How it compares to other forms

The two are different vitamers, so their molar masses alone do not give equal vitamin B6 per gram. Agree the declaration basis with your regulatory team before you set the input quantity for P5P.