| HS Code | 146043 |
| Chemical Name | Pyridoxine Hydrochloride |
| Cas Number | 58-56-0 |
| Molecular Formula | C8H11NO3·HCl |
| Molecular Weight | 205.64 g/mol |
| Description | White or almost white crystalline powder |
| Solubility | Freely soluble in water, slightly soluble in ethanol, insoluble in ether |
| Assay | 99.0% - 100.5% on dried basis |
| Ph | 2.5 - 3.5 (5% aqueous solution) |
| Related Substances | Complies with pharmacopoeial limits |
| Application | Suitable for oral and injectable dosage forms including tablets, capsules, granules and injections |
| Storage | Store in a cool, dry place, protected from light |
As an accredited VB6 Hcl Pharma Grade API for Tablet / Capsule / Granule / Injection, Oral & Injectable factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Packed in 25 kg sealed double-lined HDPE drums with tamper-evident closure, labeled for oral and injectable pharmaceutical use. |
| Container Loading (20′ FCL) | 20' FCL loading of VB6 HCl Pharma Grade API: moisture-protected, palletized drums/packs, secured for oral/injectable use, ensuring purity and safety. |
| Shipping | This pharmaceutical-grade VB6 HCl API is shipped in secure, sealed containers to maintain purity and stability. Transport complies with international safety regulations, with proper documentation for oral and injectable applications. Each shipment is carefully labeled and handled to ensure safe, timely delivery for tablet, capsule, granule, and injection manufacturing. |
| Storage | Store in a cool, dry, well-ventilated area below 30°C. Protect from moisture, direct sunlight, and excessive heat. Keep the container tightly closed when not in use. Avoid contact with incompatible materials and strong oxidizers. Use appropriate personal protective equipment during handling. Ensure the storage area is clearly labelled and secure. |
| Shelf Life | Shelf life is 24 months from manufacture date when stored in sealed, light-resistant containers under cool, dry conditions. |
At a production site running high-dose pyridoxine hydrochloride capsules for pyridoxine-dependent epilepsy, the 250 mg strength is processed as a direct-fill powder blend in which the API reaches 62.5% w/w of a 400 mg size 0 capsule fill, while the 50 mg strength is filled as 50 mg in a 150 mg size 3 fill, equivalent to 33.3% w/w. Because maintenance dosing in pyridoxine-dependent epilepsy can require more than 100 mg/day, the 250 mg capsule reduces capsule count and is preferred over multiple 50 mg units. The 62.5% w/w loading leaves only 34.0% w/w spray-dried lactose, 2.0% w/w microcrystalline cellulose PH102, 0.5% w/w colloidal silicon dioxide, and 1.0% w/w sodium stearyl fumarate in the blend. Sodium stearyl fumarate is substituted for magnesium stearate because high API loadings and blender residence times above 20 minutes can produce a hydrophobic lubricant film that slows dissolution. Compliance is anchored to USP <905> uniformity of dosage units, with an acceptance value not more than 15.0; NIR blend uniformity is controlled to an RSD below 4.0% before encapsulation. Dissolution testing per USP <711> uses 900 mL of 0.1 N hydrochloric acid at 37 °C, paddle at 50 rpm, and Q=80% at 45 minutes; elemental impurity limits follow ICH Q3D. The blend is dried to LOD below 0.5% w/w before mixing to avoid API adhesion to the dosator nozzle, then blended in a 600 L bin blender at 10 rpm for 15 minutes before final lubricant addition. Encapsulation is performed on an intermittent-motion capsule filler fitted with dosator nozzles and pin plates; fill weight is monitored every 15 minutes with a ±5.0% alert limit and ±7.5% action limit. The terminal dosage form is a hard gelatin or hydroxypropyl methylcellulose capsule for oral administration.
Dose uniformity in a 5 mg pyridoxine hydrochloride dispersible granule sachet is governed not by the API assay method but by the distribution of a 0.5% w/w API fraction across a 1.0 g fill; a 10 mg sachet using a 2.0 g fill maintains the same ratio and the same low-dose segregation risk. Pyridoxine hydrochloride is first dissolved in purified water together with povidone K30, so that the binder spray delivers the active agent as a molecular dispersion onto fluidized lactose monohydrate and microcrystalline cellulose PH101 particles. Fluid-bed top-spray granulation is run on a Glatt GPCG 5 with inlet air 65–70 °C, product temperature 32–36 °C, atomization pressure 2.5 bar, and spray rate 15–25 g/min; final loss on drying is controlled at 2.0–3.0% w/w. If the API were added as a dry powder instead of a solution, the low mass fraction would generate top-to-bottom segregation and fail USP <905> content uniformity with RSD above 5.0%. Acceptance criteria are derived from Ph. Eur. 2.9.40 and USP <905>, with single-dose mass uniformity per Ph. Eur. 2.9.5. Granulate fines below 125 µm are limited to 15.0% w/w because fines migrate to the bottom of the sachet during filling and create subpotent top portions. Sieving through 0.8 mm and reducing fines via end-point LOD control are therefore critical. Elemental impurity and residual solvent limits follow ICH Q3D and ICH Q3C. The terminal dosage form is a single-dose aluminum/polyethylene sachet containing dispersible granules for reconstitution in 10 mL water at 25 °C before oral administration.
Production-scale records for a neurotropic combination tablet containing thiamine mononitrate 100 mg, pyridoxine hydrochloride 100 mg, and cyanocobalamin 0.05 mg show that the pyridoxine HCl occupies 16.1% w/w of a 620 mg core, but its aqueous microclimate pH of 2.5–3.2 creates a chemical incompatibility with cyanocobalamin. Cyanocobalamin is acid-sensitive and must not be wetted in the same granulation with pyridoxine hydrochloride. The process therefore separates the two APIs: thiamine mononitrate and pyridoxine hydrochloride are wet-granulated in a high-shear mixer with aqueous povidone K30 5.0% w/w, wet-milled through 1.5 mm, dried in a fluid-bed dryer at inlet 60 °C to LOD 2.0–2.5% w/w, and dry-milled through 0.8 mm. Cyanocobalamin is prepared as a 1.0% w/w trituration in dicalcium phosphate and added to the external phase together with croscarmellose sodium 2.0% w/w and sodium stearyl fumarate 0.5% w/w; this keeps the light- and acid-sensitive vitamin away from the acidic granule surface. The external phase is blended in a 300 L bin blender at 8 rpm for 10 minutes, then compressed on a rotary press using 8.5 mm round concave tooling at 8–14 kN, with hardness 60–90 N and friability below 0.8% w/w per USP <1216>. Uniformity of dosage units must comply with USP <905>, dissolution with USP <711> in 900 mL of 0.1 N HCl, and elemental impurities with ICH Q3D. The compressed core is film-coated with a hydroxypropyl methylcellulose system containing iron oxide pigments to reduce light transmission to the cyanocobalamin component. The terminal finished product is a film-coated immediate-release neurotropic tablet for oral use.
In tuberculosis treatment protocols where oral isoniazid 300 mg/day is prescribed, pyridoxine hydrochloride is co-administered as a 10 mg or 50 mg immediate-release tablet to reduce the incidence of isoniazid-induced peripheral neuropathy. In the 10 mg strength, the API is 8.3% w/w of a 120 mg core, while in the 50 mg strength it is 25.0% w/w of a 200 mg core. The 10 mg formulation is processed by geometric dilution in 1:10 steps with lactose monohydrate before full blending; if the API is dumped directly into the final blend, production batch data show content uniformity failures under USP <905> with acceptance values exceeding 15.0. Blending is carried out in a 150 L bin blender at 10 rpm for 15 minutes, followed by lubricant addition of magnesium stearate 0.5% w/w with an additional 3 minutes of blending. Compression uses an 8 mm round flat-faced bevel punch on a rotary tablet press at 7–12 kN; tablet hardness is controlled at 50–80 N, friability below 0.8% w/w per USP <1216>, and disintegration below 15 minutes per USP <701>. Dissolution testing follows USP <711> in 900 mL of 0.1 N HCl with Q=80% at 45 minutes. Residual solvents and elemental impurities are controlled under ICH Q3C and ICH Q3D. The terminal dosage form is a film-coated immediate-release tablet packaged in blister packs to limit moisture uptake.
Injectable pyridoxine hydrochloride at 100 mg/mL is manufactured by terminal moist-heat sterilization rather than by aseptic filtration as the sole control; the solution concentration is 10.0% w/v in Water for Injection. The solution is compounded under nitrogen overlay in a jacketed stainless vessel at 20–30 °C, and the pH is adjusted with dilute hydrochloric acid or sodium hydroxide to 2.5–3.5; this range keeps the API in its most chemically stable zone while avoiding the injection-site pain associated with pH below 2.0. The bulk solution is passed through two 0.22 µm polyvinylidene fluoride membrane filters in series and filled into 2 mL Type I amber glass ampoules with headspace oxygen below 2.0% v/v. Terminal sterilization is performed in a saturated-steam autoclave at 121 °C for 15 minutes, with a minimum F0 of 8 minutes; container headspace oxygen is confirmed by electrochemical oxygen analysis after cooling. Manufacturing follows EU GMP Annex 1 for terminally sterilized products. Temperature mapping of all ampoule positions is performed during load validation, and the slowest-to-heat location is used for F0 calculation because published stability data for this specific container-load configuration are limited. Release testing includes sterility per USP <71>, bacterial endotoxins per USP <85> with limits derived from the maximum bolus dose, particulate matter per USP <788>, and assay by stability-indicating HPLC per USP <621>. The terminal dosage form is a 100 mg/mL pyridoxine hydrochloride injection in 1 mL or 2 mL single-use amber ampoules for intramuscular or slow intravenous administration after dilution with 0.9% sodium chloride when required.
When adult parenteral nutrition multivitamin powders contain pyridoxine hydrochloride, the required daily amount is only 3 mg per vial, and the API addition ratio is 0.6% w/w in a 500 mg lyophilized cake. This low mass fraction precludes dry mixing and requires the active agent to be dissolved in the bulk solution before filtration. Aseptic processing per EU GMP Annex 1 uses a 0.22 µm polyethersulfone filter and fills 5 mL Type I glass vials with a nitrogen overlay. Before lyophilization, the bulk solution is held at 2–8 °C for no more than 12 hours to limit oxidation; storage of unstoppered vials during loading is minimized. The lyophilization cycle proceeds from a freezing step at −40 °C for 6 hours, primary drying at −20 °C and 150 µbar for 20 hours, and secondary drying at 25 °C for 6 hours; residual moisture is confirmed below 2.0% w/w by USP <921>. Release testing includes sterility per USP <71>, bacterial endotoxins per USP <85>, and elemental impurities per ICH Q3D. The terminal dosage form is a sterile lyophilized cake or powder for reconstitution with Water for Injection and subsequent dilution into a parenteral nutrition admixture. Published stability data for this specific lyophilized multivitamin matrix are limited to product-specific registration files; cross-product extrapolation of degradant profiles, residual moisture limits, or reconstitution stability is not recommended. Storage requires protection from light and continuous refrigeration before reconstitution, because moisture ingress above 3.0% w/w accelerates browning and pyridoxine HCl degradation.
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Product VB6 Hcl Pharma Grade API is pyridoxine hydrochloride, CAS 58-56-0, with molecular formula C8H11NO3·HCl and molecular weight 205.64 g/mol. It is released as a white or almost white crystalline powder intended for tablet, capsule, granule, oral liquid, and injectable preparation. The substance is controlled under Ph. Eur. monograph 0245, the corresponding USP Pyridoxine Hydrochloride monograph, ICH Q7, ICH Q3C, and ICH Q3D. The hydrochloride salt dissolves at approximately 1 g in 4.5 mL of water at 20–25 °C and 1 g in 90 mL of ethanol. The pH of a 5% aqueous solution falls between 2.3 and 3.5. The oral grade is controlled for assay, related substances, residual solvents, elemental impurities, and particle size; the injectable grade adds bacterial endotoxin and microbial quality testing. The product model designation separates the pharmaceutical-grade API from feed-grade pyridoxine hydrochloride, which may not carry the same residual solvent, elemental impurity, or injectable-use documentation. Table 1 summarises the principal release parameters.
| Parameter | Acceptance criterion | Method |
|---|---|---|
| Appearance | White or almost white crystalline powder | Ph. Eur. 0245 |
| Assay | 99.0–101.0% dried basis | HPLC against certified reference standard |
| Loss on drying | ≤0.5% | Ph. Eur. 2.2.32 |
| pH, 5% solution | 2.3–3.5 | Ph. Eur. 2.2.3 |
| Sulphated ash | ≤0.1% | Ph. Eur. 2.4.14 |
| Heavy metals | ≤10 ppm | Ph. Eur. 2.4.8 |
| Related substances: total | ≤0.5% | HPLC, area normalisation |
| Residual solvents: ethanol | ≤5000 ppm | ICH Q3C headspace GC |
| Particle size D90, oral grade | ≤250 µm | Laser diffraction, dry dispersion |
| Bacterial endotoxins, injectable grade | Dose-calculated; typical in-house limit ≤1.0 EU/mg | Ph. Eur. 2.6.14 |
When a formulator substitutes pyridoxine hydrochloride for pyridoxine base in an aqueous wet granulation, the change alters granulation fluid requirements, drying behaviour, and lubricant compatibility. Pyridoxine hydrochloride is freely soluble in water; therefore, a portion of the drug dissolves in the binder solution and migrates to granule surfaces during fluid-bed or tray drying. The resulting surface enrichment can produce content variation in sieve fractions below 75 µm and above 250 µm. On a production high-shear granulator fitted with a 300 L bowl and a 250 mm chopper, shear-induced heating should be controlled below 35 °C. Vacuum drying at 40 °C and 80–100 mbar reduces surface migration compared with open tray drying at 60 °C. Because the salt forms an acidic aqueous solution with pH 2.3–3.5, contact with uncoated mild steel is minimised; granulator and dryer contact surfaces are typically specified in 316L stainless steel. Pyridoxine base does not create the same localised acid environment, but its slower dissolution in aqueous binder can leave undissolved agglomerates and contribute to tablet capping on compression. Consequently, the hydrochloride salt is preferred for routine oral solid dosage forms requiring reproducible dissolution and content uniformity. The formulation incompatibility boundaries include strong alkalis, carbonates, and effervescent matrices based on sodium bicarbonate; exposure above pH 5.5 accelerates oxidative degradation and discoloration. If an effervescent tablet is required, pyridoxine hydrochloride should be separated from the carbonate component by a protective lipid or polymer barrier. This requirement follows from pH-stability data for pyridoxine in aqueous solution rather than a single manufacturer-specific stability study.
Direct compression of 10 mg pyridoxine hydrochloride tablets is limited by flow and segregation rather than chemical instability. The crystalline powder has a bulk density of 0.45–0.60 g/mL and a tapped density of 0.65–0.80 g/mL, which produces a Hausner ratio of 1.20–1.35. This classifies the API as passable-to-poor flowing under USP powder flow evaluation; mechanical force feeding is required when compression speed exceeds 40 rpm on a rotary tablet press. A low-dose direct compression formulation at 10 mg API per 250 mg tablet places the drug at 4% w/w, which is high enough to retain blend uniformity after geometric dilution but low enough to show electrostatic adhesion to hopper walls in dry conditions below 30% RH. If the formulation drops to 2.5 mg or 5 mg per tablet, drug content falls below 2% w/w, and direct compression is not recommended without ordered mixing or dry granulation. For capsule filling on an automatic dosator machine, powder flow limitations are managed with a fill weight of 180–220 mg and a 0 or 00 capsule body; dosator pin height is adjusted to achieve plug density between 0.55 and 0.65 g/mL. Magnesium stearate is limited to 0.5–1.0% w/w, and blending time is held to 3–5 min to prevent hydrophobic film formation on the API surface. Dissolution testing of immediate-release pyridoxine hydrochloride tablets is performed by USP 711; high aqueous solubility makes dissolution failure unlikely unless lubricant over-blending occurs. Published data for this specific formulation is limited; the processing boundaries are derived from standard powder flow and low-dose blending practice rather than a single finished-product stability file.
For injectable and oral liquid dosage forms, the product is supplied as a non-sterile API; the finished injection or oral solution must be prepared by dissolving the powder in Water for Injection and either terminally sterilising the solution or passing it through a validated sterilising membrane. The aqueous solubility of approximately 1 g in 4.5 mL at 20–25 °C allows a 100 mg/mL injection concentrate without organic co-solvents. pH adjustment with sodium hydroxide or hydrochloric acid is required because a plain aqueous solution lies between pH 2.3 and 3.5. The injectable-grade release includes bacterial endotoxin testing by Ph. Eur. 2.6.14 using a quantitative kinetic chromogenic LAL method. The endotoxin limit is derived from Ph. Eur. 5.1.10 using the formula limit = K/M, where K is 5 EU/kg for intravenous injection and M is the maximum bolus dose in mg/kg. For a 70 kg adult receiving 100 mg pyridoxine hydrochloride, the calculated API limit is 3.5 EU/mg; many injectable-grade suppliers impose a tighter in-house release limit of ≤1.0 EU/mg to accommodate downstream adsorption losses. Subvisible particulate matter is tested in the finished injection by light obscuration particle count under USP 788; the API is dissolved and prefiltered through a 0.45 µm membrane before measurement. The API should not be mixed with strong oxidising agents, trace-metal-ion-rich water, or alkaline buffers above pH 5.5, because pyridoxine is susceptible to metal-catalysed oxidation. Aqueous pyridoxine solutions show photodegradation, so filling lines for injectables should use amber glass vials or protective light screens. Terminal sterilisation is possible in acidic solution, but a sterilising filtration process is common where the finished formulation contains oxygen-sensitive additives.
The residual solvent profile is controlled by ICH Q3C. Ethanol and isopropyl alcohol are Class 3 solvents with a concentration limit of 5000 ppm each; methanol, if present, is treated as a Class 2 solvent with a limit of 3000 ppm. Headspace gas chromatography with flame-ionisation detection is used after dissolving the sample in water and applying a temperature program from 40 °C to 220 °C at 10 °C/min. The elemental impurity strategy follows ICH Q3D Option 1. For oral drug products, the permitted daily exposure values for lead, cadmium, arsenic, and mercury are 5 µg/day, 5 µg/day, 15 µg/day, and 30 µg/day, respectively. For injectable drug products, the corresponding limits are 5 µg/day, 2 µg/day, 15 µg/day, and 3 µg/day. Routine release testing by inductively coupled plasma mass spectrometry quantifies these elements, with practical quantitation limits below 10 ng/g for lead and cadmium in the dissolved solid. Where the synthesis route is documented to be free of specific catalysts, validated skip testing can be applied under ICH Q3D risk assessment. Heavy metal testing by the older colorimetric method is retained only for pharmacopoeial compliance where specified; its limit is ≤10 ppm. These controls distinguish pharmaceutical-grade pyridoxine hydrochloride from food/feed-grade material, which may not provide the same elemental impurity statement or injectable endotoxin documentation.
In formulations where hepatic conversion to pyridoxal 5-phosphate is not the limiting factor, pyridoxine hydrochloride is used because of its crystalline stability, high aqueous solubility, and established monograph controls. Pyridoxal 5-phosphate is the active coenzyme form and may be selected for patients with impaired liver function or for specific injectable hepatoprotective combinations, but it is more sensitive to light, oxidation, and pH extremes than the hydrochloride salt. The phosphate ester can undergo hydrolysis in acidic media below pH 2.0, which narrows its use in long-term oral liquid formulations. Pyridoxine base is less ionised and can be incorporated into non-aqueous or lipid-based systems where protonated salt forms partition poorly; however, the base has different dissolution behaviour and can require acidification for complete dissolution in water. The hydrochloride salt is compatible with microcrystalline cellulose, lactose monohydrate, pregelatinised starch, croscarmellose sodium, and sodium stearyl fumarate. It is incompatible with strong oxidising agents, strong bases, sodium bicarbonate, and trace-metal-rich wet granulation water. Food/feed grades may report an assay of 98.0–101.0% but do not routinely provide injectable-grade endotoxin data or ICH Q3D elemental impurity statements needed for pharmaceutical dossier submission. These compatibility boundaries are based on the oxidation and pH-degradation behaviour of the pyridoxine ring system.
Long-term stability of the dry API in double polyethylene-lined fibre drums at 25 °C/60% RH maintains assay within 99.0–101.0% and loss on drying below 0.5% for up to 24 months when the container is kept tightly closed and protected from light. At accelerated conditions of 40 °C/75% RH, moisture uptake in an open dish is measurable within 24 h; in closed commercial packaging the moisture gain is generally below 0.2%. Light exposure has a larger effect on aqueous solutions than on dry powder, but the dry powder should nevertheless be stored away from direct sunlight and ultraviolet sources. Tablet and capsule manufacturers should pre-dry the API when in-process relative humidity exceeds 60% before dry granulation or direct compression. No antioxidant is required for dry solid dosage forms; aqueous parenteral solutions may use nitrogen blanketing and light protection rather than EDTA, because trace metal complexation must be selected against the final solution pH. Residual moisture after wet granulation is typically controlled between 1.5 and 2.5% before compression to avoid granule sticking and punch filming.
