Pyridoxine Hydrochloride, also known as Pyridoxine HCl, Pyridoxol Hydrochloride and Vitamin B6 Hydrochloride, is the hydrochloride salt of pyridoxine and an important pharmaceutical vitamin API. It is a water-soluble form of vitamin B6 used in pharmaceutical preparations, nutritional products and vitamin formulations. The compound has the molecular formula C₈H₁₁NO₃·HCl and a molecular weight of 205.64 g/mol. Its CAS Number is 58-56-0.
Pyridoxine Hydrochloride is described as colorless or white crystals or a white crystalline powder. It is stable in air but is slowly affected by sunlight, making appropriate light-protective packaging important for pharmaceutical handling. The USP/FCC description states that its solutions are acidic and that the substance melts at approximately 206°C with some decomposition.
Product Name: Pyridoxine Hydrochloride
Synonyms: Pyridoxine HCl, Pyridoxol Hydrochloride, Vitamin B6 Hydrochloride
CAS Number: 58-56-0
Molecular Formula: C₈H₁₁NO₃·HCl
Molecular Weight: 205.64 g/mol
Chemical Class: Vitamin B6 / Pyridine derivative
API Form: Hydrochloride salt
Appearance: Colorless or white crystals / white crystalline powder
Water Solubility: Freely soluble in water
Light Sensitivity: Slowly affected by sunlight
PubChem confirms Pyridoxine Hydrochloride as the hydrochloride salt form of pyridoxine and reports a molecular weight of 205.64 g/mol.
Pyridoxine is one of the forms of vitamin B6. In biological systems, vitamin B6 compounds participate in enzymatic reactions through their active coenzyme forms, particularly pyridoxal 5'-phosphate. Pyridoxine Hydrochloride is therefore widely used as a source of vitamin B6 in pharmaceutical and nutritional preparations.
The API has established pharmacopoeial recognition. USP defines Pyridoxine Hydrochloride as containing NLT 98.0% and NMT 102.0% of pyridoxine hydrochloride, calculated on the dried basis.
USP identification includes infrared absorption and chloride identification. The USP assay method is chromatographic, making the CMS HPLC assay field appropriate for this product.
Pyridoxine Hydrochloride is used as an active ingredient in vitamin B6 pharmaceutical products and combination vitamin preparations. It may be incorporated into oral vitamin formulations and, where appropriately formulated and approved, parenteral preparations.
Official DailyMed labeling for Pyridoxine Hydrochloride Injection identifies the API as a colorless or white crystal or white crystalline powder and states that one gram dissolves in approximately 5 mL of water. The injectable product is a sterile aqueous preparation containing pyridoxine hydrochloride.
Pyridoxine Hydrochloride is also used in nutritional and dietary formulations where vitamin B6 supplementation is required. Its water solubility and established pharmaceutical quality standards make it suitable for a wide range of formulation applications.
Pyridoxine Hydrochloride has well-defined pharmacopoeial quality requirements. USP specifies an assay range of 98.0–102.0% on the dried basis. Loss on Drying is NMT 0.5%, while Residue on Ignition is NMT 0.1%. The historical/current USP text also specifies heavy metals at NMT 0.003%, equivalent to 30 ppm.
The USP assay is based on liquid chromatography, while identification includes IR and chloride testing. A USP/EP certificate also reports an EP assay range of 99.0–101.0% on the dried basis, EP pH of 2.4–3.0, sulfated ash NMT 0.1%, and related substances including specified impurity B NMT 0.15%, unspecified impurities NMT 0.10%, and total impurities NMT 0.20%.
It is important to distinguish Residue on Ignition from Sulfated Ash. USP provides an ROI value of NMT 0.1%, whereas the EP certificate reports sulfated ash NMT 0.1%. These are not interchangeable tests.
Pyridoxine Hydrochloride manufacturing requires controlled processing and analytical verification to maintain consistent pharmaceutical quality. Important quality attributes include identity, assay, moisture, inorganic residue, elemental impurities, chloride content and related substances.
Batch-wise analytical testing can be performed against the applicable USP, EP or customer-approved specification. Manufacturing controls should address raw-material quality, processing conditions, drying, packaging and protection from excessive light exposure.
Pyridoxine Hydrochloride should be protected from excessive light and stored in suitable tight, light-resistant containers. USP references specify preservation in tight, light-resistant containers.
The material is stable in air but can be slowly affected by sunlight. Appropriate packaging and storage therefore help maintain its chemical quality during transportation and pharmaceutical manufacturing.
Typical documentation for Pyridoxine Hydrochloride API may include:
Pyridoxine Hydrochloride is a well-established Vitamin B6 API with recognized USP and European pharmacopoeial quality requirements. Its defined chemical identity, high assay requirements, controlled moisture and impurity profile support its use in pharmaceutical and nutritional manufacturing.
The combination of established analytical methods, defined quality parameters and broad pharmaceutical application makes Pyridoxine Hydrochloride an important vitamin API for formulation development and commercial pharmaceutical production.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 0.5% |
| Residue on Ignition | NMT 0.1% |
| Heavy Metals | NMT 30 ppm |
| Individual Impurity | NMT 0.10% |
| Total Impurities | NMT 0.20% |