Pyridoxine Hydrochloride Tablets

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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1 DEFINITION

Pyridoxine Hydrochloride Tablets contain NLT 95.0% and NMT 115.0% of the labeled amount of pyridoxine hydrochloride (C₈H₁₁NO₃ · HCl).

2 IDENTIFICATION

A. Reaction with Ferric Ion

Sample: Equivalent to 100 mg of pyridoxine hydrochloride from a quantity of powdered Tablets

Analysis: Add 5 mL of water to the Sample. Shake the mixture, filter into a test tube, and add 2 or 3 drops of ferric chloride TS.

Acceptance criteria: An orange to deep red color is produced.

3 ASSAY

Procedure

Buffer: Dissolve 16 g of ammonium chloride in 70 mL of water, add 16 mL of ammonium hydroxide, dilute with water to 100 mL, and filter.

Color reagent: 0.4 mg/mL of 2,6-dichloroquinone chlorimide in isopropyl alcohol.

[Note—Store the solution in a refrigerator, and use within one month. Do not use the solution if it has become pink.]

Standard stock solution: 0.1 mg/mL of USP Pyridoxine Hydrochloride RS in 0.1 N hydrochloric acid.

[Note—Keep the solution in an amber bottle, in a cool place.]

Standard solution: 10 µg/mL of USP Pyridoxine Hydrochloride RS from the Standard stock solution diluted with water.

[Note—Prepare this solution daily as needed.]

Sample solution: Weigh and finely powder NLT 20 Tablets. Transfer, with the aid of water, a portion of the powdered Tablets to a conical flask. Add 0.5 mL hydrochloric acid per each mg of the nominal amount of pyridoxine hydrochloride taken, then dilute with water to about 0.04 mg/mL, and heat on a steam bath until disintegration is complete. Cool, dilute with water to 10 µg/mL, and centrifuge a portion of the mixture.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.)

Mode: Visible

Analytical wavelength: 650 nm

Blank: Water

Analysis

Samples: Standard solution and Sample solution

Separately add 25.0 mL of isopropyl alcohol to 5 mL each of the Standard solution and the Sample solution. Transfer 5 mL of each of the resulting solutions to separate, glass-stoppered, 25-mL graduated cylinders or test tubes, and add in succession, mixing after each addition, 1.0 mL of Buffer, 1.0 mL of a 0.2-g/mL solution of sodium acetate, and 1.0 mL of water. Cool to 25°, add 1.0 mL of Color reagent, and shake vigorously for 10 s, accurately timed. Determine the absorbance 90 s after the addition of the Color reagent. Repeat the procedure both for the Standard solution and the Sample solution, but substitute 1.0 mL of a 50-mg/mL solution of boric acid solution for the 1.0 mL of water.

[Note—Make the reading promptly to avoid errors due to fading of the color.]

Calculate the percentage of the labeled amount of pyridoxine hydrochloride (C₈H₁₁NO₃ · HCl) in the portion of Tablets taken:

Result = (A − A′)/(Aₛ − A′ₛ) × (Cₛ/Cᵤ) × 100

Aᵤ = absorbance of Sample solution with water

A′ᵤ = absorbance of Sample solution with boric acid

Aₛ = absorbance of Standard solution with water

A′ₛ = absorbance of Standard solution with boric acid

Cₛ = concentration of USP Pyridoxine Hydrochloride RS in the Standard solution (µg/mL)

Cᵤ = nominal concentration of pyridoxine hydrochloride in the Sample solution (µg/mL)

Acceptance criteria: 95.0%–115.0%

4 PERFORMANCE TESTS

Dissolution, Procedure for a Pooled Sample 〈711〉

Medium: Water; 900 mL

Apparatus 2: 50 rpm

Time: 45 min

Mobile phase: A mixture of methanol, glacial acetic acid, and water (27:1:73) containing 1.40 mg/mL of sodium 1-hexanesulfonate

Standard solution: Known concentration of USP Pyridoxine Hydrochloride RS in Medium

Sample solution: Filtered portion of the solution under test, suitably diluted with Medium if necessary

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 280 nm

Column: 3.9-mm × 30-cm; packing L1

Flow rate: 1 mL/min

Injection size: 10 µL

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 3.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of pyridoxine hydrochloride (C₈H₁₁NO₃ · HCl) dissolved:

Result = (rᵤ/rₛ) × (C × D × V/L) × 100

rᵤ = peak area of pyridoxine from the Sample solution

rₛ = peak area of pyridoxine from the Standard solution

C = concentration of USP Pyridoxine Hydrochloride RS in the Standard solution (mg/mL)

D = dilution factor for the Sample solution

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 75% (Q) of the labeled amount of pyridoxine hydrochloride (C₈H₁₁NO₃ · HCl) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

Content uniformity

Standard solution: 10 µg/mL of USP Pyridoxine Hydrochloride RS in dilute hydrochloric acid (1 in 100)

Sample solution: Transfer 1 Tablet, finely powdered, to a 500-mL volumetric flask containing 300 mL of water, shake for 30 min, and dilute with water to volume. Filter a portion of the mixture, discarding the first 25 mL of the filtrate. Dilute an aliquot of the filtrate with dilute hydrochloric acid (1 in 100) to obtain 10 µg/mL of pyridoxine hydrochloride.

Instrumental conditions

(See Ultraviolet-Visible Spectroscopy 〈857〉.)

Mode: UV

Analytical wavelength: 290 nm

Cell: 1 cm

Blank: Dilute hydrochloric acid (1 in 100)

Analysis

Samples: Standard solution and Sample solution

Determine the absorbances of the Standard solution and Sample solution.

Calculate the percentage of pyridoxine hydrochloride (C₈H₁₁NO₃ · HCl) in the portion of Tablets taken:

Result = (Aᵤ/Aₛ) × (Cₛ/Cᵤ) × (100/L)

Aᵤ = absorbance of the Sample solution

Aₛ = absorbance of the Standard solution

Cₛ = concentration of USP Pyridoxine Hydrochloride RS in the Standard solution (mg/mL)

Cᵤ = nominal concentration of pyridoxine hydrochloride in the Sample solution (mg/mL)

L = label claim (mg/Tablet)

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers, protected from light.

USP Reference Standards 〈11〉

USP Pyridoxine Hydrochloride RS