Phenazopyridine 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

Phenazopyridine Hydrochloride Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of phenazopyridine hydrochloride (C₁₁H₁₁N₅·HCI).

2 IDENTIFICATION

A. The UV spectrum of the phenazopyridine peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

B. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 PROCEDURE

Solution A: 20 mM ammonium acetate in water

Solution B: Acetonitrile

Mobile phase: See Table 1.

Table 1

Diluent: Acetonitrile and water (10:90)

Standard solution: 0.03 mg/mL of USP Phenazopyridine Hydrochloride RS in Diluent

Sample stock solution: Nominally 0.3 mg/mL of phenazopyridine hydrochloride from NLT 20 finely powdered Tablets in Diluent, prepared as follows. Transfer a suitable amount of the powder to a suitable volumetric flask. Add Diluent equivalent to 75% of the flask volume and sonicate for 15 min. Allow the solution to cool to room temperature, dilute with Diluent to volume, and centrifuge.

Sample solution: Nominally equivalent to 0.03 mg/mL of phenazopyridine hydrochloride in Diluent from the Sample stock solution

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 280 nm. For Identification A, use a diode array detector in the range of 200-600 nm.

Column: 4.6-mm x 25-cm; 5-µm packing L1

Flow rate: 1 mL/min

Injection volume: 20 µL

3.3 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 1.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of phenazopyridine hydrochloride (C₁₁H₁₁N₅·HCI) in the portion of Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

C_S = concentration of USP Phenazopyridine Hydrochloride RS in the Standard solution (mg/mL)

C_U = nominal concentration of phenazopyridine hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: Water; 900 mL

Apparatus 2: 50 rpm

Time: 45 min

Standard solution: USP Phenazopyridine Hydrochloride RS in Medium

Sample solution: Filter portions of the solution under test and suitably dilute with Medium to a concentration that is similar to that of the Standard solution.

Instrumental conditions

Mode: UV

Analytical wavelength: 422 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the quantity of phenazopyridine hydrochloride (C₁₁H₁₁N₅·HCI) dissolved by using UV absorption from the Sample solution in comparison with the Standard solution.

Tolerances: NLT 75% (Q) of f the labeled amount of phenazopyridine hydrochloride (C₁₁H₁₁N₅·HCI) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

Solution A, Solution B, Mobile phase, and Diluent: Proceed as directed in the Assay.

Sensitivity solution: 0.25 µg/mL of USP Phenazopyridine Hydrochloride RS in Diluent

Standard solution: 0.001 mg/mL of USP Phenazopyridine Hydrochloride RS in Diluent

Sample solution: Nominally 0.5 mg/mL of phenazopyridine hydrochloride from NLT 20 finely powdered Tablets in Diluent, prepared as follows. Transfer a suitable amount of the powder to a suitable volumetric flask. Add Diluent equivalent to 60% of the flask volume and sonicate for 15 min. Allow the solution to cool to room temperature and dilute with Diluent to volume. Centrifuge the solution and dilute the supernatant with Diluent to obtain 0.5 mg/mL of phenazopyridine hydrochloride.

Chromatographic system: Proceed as directed in the Assay except for the Detector.

Detector: UV 240 nm

System suitability

Samples: Sensitivity solution and Standard solution

Suitability requirements

Tailing factor: NMT 1.5 for the phenazopyridine peak, Standard solution

Relative standard deviation: NMT 3.0% for the phenazopyridine peak, Standard solution

Signal-to-noise ratio: NLT 30 for the phenazopyridine peak, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of any individual unspecified impurity in the portion of the Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) x 100

r_U = peak response of each individual unspecified impurity from the Sample solution

r_S = peak response of phenazopyridine from the Standard solution

C_S = concentration of USP Phenazopyridine Hydrochloride RS in the Standard solution (mg/mL)

C_U = nominal concentration of phenazopyridine hydrochloride in the Sample solution (mg/mL)

Acceptance criteria: See Table 2. Disregard any impurity peaks less than 0.05%.

Table 2

^a For identification only. These are process impurities monitored in the drug substance and are not included in the total impurities.

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in tight containers. Store at controlled room temperature.

6.2 USP REFERENCE STANDARDS (11)

USP Phenazopyridine Hydrochloride RS