Nadolol and Bendroflumethiazide 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

Nadolol and Bendroflumethiazide Tablets contain NLT 90.0% and NMT 110.0% of the labeled amounts of nadolol (C₁₇H₂₇NO₄) and bendroflumethiazide (C₁₅H₁₄F₃N₃O₄S₂).

2 IDENTIFICATION

Change to read:

A. The retention times of the two major peaks of the Sample solution correspond to those of the Standard solution, as obtained in the Assay.

Add the following:

B. The UV spectra of the two major peaks of the Sample solution correspond to those of the Standard solution, as obtained in the Assay.

3 ASSAY

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3.1 Procedure

[Caution-Use low-actinic glassware for the Sample solution and the Standard solution.]

Mobile phase: Transfer 5.62 g of anhydrous sodium chloride and 1.97 g of sodium acetate to 1000 mL of water in a 2-L volumetric flask. Add 4.0 mL of glacial acetic acid and 800 mL of methanol. Dilute with water to volume.

System suitability solution: 0.4 mg/mL each of USP Nadolol RS and USP 2,4-Disulfamyl-5-trifluoromethylaniline RS in methanol

Standard solution: 0.4 mg/mL of USP Nadolol RS and 0.4J mg/mL of USP Bendroflumethiazide RS in methanol, where J is the ratio of the labeled amount of bendroflumethiazide, in milligrams, to the labeled amount of nadolol, in mg/Tablet

Sample solution: Nominally equivalent to 0.4 mg/mL of nadolol in methanol prepared as follows. Transfer a portion of finely powdered Tablets (NLT 20), equivalent to 40 mg of nadolol, to a 100-mL volumetric flask. Add methanol, and sonicate for 15 min with occasional shaking. Dilute with methanol to volume, and centrifuge.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 270 nm. For Identification B, use a diode array detector in the range of 210–400 nm.
• Column: 3.9-mm × 30-cm; 10-µm packing L11
• Flow rate: 1.5 mL/min
• Injection volume: 20 µL
• Run time: NLT 2 times the retention time of bendroflumethiazide

System suitability

Samples: System suitability solution and Standard solution

[Note-The relative retention times for nadolol and bendroflumethiazide are about 0.3 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 1.4 between the solvent and 2,4-disulfamyl-5-trifluoromethylaniline peaks; NLT 1.4 between the 2,4-disulfamyl-5-trifluoromethylaniline and nadolol peaks, System suitability solution; and NLT 1.7 between the nadolol and bendroflumethiazide peaks, Standard solution

Relative standard deviation: NMT 3.0% for the nadolol and bendroflumethiazide peaks, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of nadolol (C₁₇H₂₇NO₄) in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of nadolol from the Sample solution

rₛ = peak response of nadolol from the Standard solution

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

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

Calculate the percentage of the labeled amount of bendroflumethiazide (C₁₅H₁₄F₃N₃O₄S₂) in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of bendroflumethiazide from the Sample solution

rₛ = peak response of bendroflumethiazide from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

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Dissolution 〈711〉, Procedure, Apparatus 1 and Apparatus 2, Immediate-Release Dosage Forms, Procedure for a pooled sample for immediate-release dosage forms

[Caution-Protect solutions from light throughout this test.]

Medium: 0.1 N hydrochloric acid; 900 mL

Apparatus 2: 50 rpm

Time: 30 min

Standard solution: Dissolve USP Nadolol RS and USP Bendroflumethiazide RS in a minimal amount of methanol, and dilute with Medium to the desired concentrations.

Sample solution: Pass a portion of the solution under test through a suitable filter. Dilute with Medium to a concentration that is similar to the Standard solution.

Chromatographic system and System suitability: Proceed as directed in the Assay.

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of nadolol (C₁₇H₂₇NO₄) or bendroflumethiazide (C₁₅H₁₄F₃N₃O₄S₂) dissolved:

Result = (rᵤ/rₛ) × Cₛ × D × V × (1/L) × 100

rᵤ = peak response of nadolol or bendroflumethiazide from the Sample solution

rₛ = peak response of nadolol or bendroflumethiazide from the Standard solution

Cₛ = concentration of USP Nadolol RS or USP Bendroflumethiazide RS in the Standard solution (mg/mL)

D = dilution factor of the Sample solution

V = volume of Medium, 900 mL

L = label claim (mg/Tablet)

Tolerances: NLT 80% (Q) of the labeled amount of nadolol (C₁₇H₂₇NO₄) and bendroflumethiazide (C₁₅H₁₄F₃N₃O₄S₂) is dissolved.

Uniformity of Dosage Units 〈905〉, Content Uniformity: Meet the requirements

5 IMPURITIES

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5.1 Organic Impurities, Procedure 1: Nadolol Related Impurities

[Caution-Protect all solutions containing nadolol from light.]

Buffer: Transfer 3.85 g of ammonium acetate into 1000 mL of water. Adjust with 5 N hydrochloric acid to a pH of 4.0.

Mobile phase: Acetonitrile and Buffer (89:11)

Standard solution: 0.016 mg/mL of USP Nadolol RS in Mobile phase

Sensitivity solution: 0.0016 mg/mL of USP Nadolol RS from the Standard solution in Mobile phase

Sample solution: Nominally 3.2 mg/mL of nadolol prepared as follows. Transfer a suitable amount, equivalent to 160 mg of nadolol, from finely powdered Tablets (NLT 20) to a suitable volumetric flask. Add Mobile phase to 80% of the volume of the flask. Shake and mix for 15 min. Dilute with Mobile phase to volume. Pass a portion of the solution through a suitable filter. Use the filtrate.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 270 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L3
• Flow rate: 1.5 mL/min
• Injection volume: 20 µL
• Run time: NLT 2 times the retention time of nadolol

System suitability

• Samples: Standard solution and Sensitivity solution
• [Note-The relative retention times for bendroflumethiazide and nadolol are 0.17 and 1.00, respectively.]
• Suitability requirements
• Tailing factor: NMT 2.0, Standard solution
• Relative standard deviation: NMT 2.0%, Standard solution
• Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of any nadolol related unspecified degradation product in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of any nadolol related unspecified degradation product from the Sample solution

rₛ = peak response of nadolol from the Standard solution

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

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

Acceptance criteria: See Table 1. The reporting threshold is 0.05%.

Table 1

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5.2 Organic Impurities, Procedure 2: Bendroflumethiazide Related Impurities

[Caution-Protect all solutions containing bendroflumethiazide from light.]

Buffer: Transfer 6.8 g of monobasic potassium phosphate into 1000 mL of water. Add 1 mL of phosphoric acid and mix. Adjust with phosphoric acid to a pH of 2.0.

Mobile phase: Acetonitrile and Buffer (38:62)

Standard stock solution A: 0.25 mg/mL of USP 2,4-Disulfamyl-5-trifluoromethylaniline RS in Mobile phase

Standard stock solution B: 0.25 mg/mL of USP Bendroflumethiazide RS in acetonitrile

Standard solution: 1.0 µg/mL each of USP 2,4-Disulfamyl-5-trifluoromethylaniline RS and USP Bendroflumethiazide RS in Mobile phase from Standard stock solution A and Standard stock solution B

Sensitivity solution: 0.1 µg/mL each of USP 2,4-Disulfamyl-5-trifluoromethylaniline RS and USP Bendroflumethiazide RS from the Standard solution in Mobile phase

Sample solution: Nominally 200 µg/mL of bendroflumethiazide prepared as follows. Transfer a suitable amount, equivalent to 10 mg of bendroflumethiazide, from finely powdered Tablets (NLT 20) to a suitable volumetric flask. Add Mobile phase to 80% of the volume of the flask. Shake and mix for 15 min. Dilute with Mobile phase to volume. Pass a portion of the solution through a suitable filter. Use the filtrate.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 270 nm
• Column: 4.6-mm × 15-cm; 5-µm packing L1
• Autosampler temperature: 2°–8°
• Flow rate: 1 mL/min
• Injection volume: 10 µL
• Run time: NLT 2 times the retention time of bendroflumethiazide

System suitability

• Samples: Standard solution and Sensitivity solution
• [Note-The relative retention times for nadolol, 2,4-disulfamyl-5-trifluoromethylaniline, and bendroflumethiazide are 0.11, 0.21, and 1.00, respectively.]
• Suitability requirements
• Tailing factor: NMT 2.0 for both 2,4-disulfamyl-5-trifluoromethylaniline and bendroflumethiazide, Standard solution
• Relative standard deviation: NMT 2.0% for both 2,4-disulfamyl-5-trifluoromethylaniline and bendroflumethiazide, Standard solution
• Signal-to-noise ratio: NLT 10 for both 2,4-disulfamyl-5-trifluoromethylaniline and bendroflumethiazide, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of 2,4-disulfamyl-5-trifluoromethylaniline in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of 2,4-disulfamyl-5-trifluoromethylaniline from the Sample solution

rₛ = peak response of 2,4-disulfamyl-5-trifluoromethylaniline from the Standard solution

Cₛ = concentration of USP 2,4-Disulfamyl-5-trifluoromethylaniline RS in the Standard solution (µg/mL)

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

Calculate the percentage of any bendroflumethiazide related unspecified degradation product in the portion of Tablets taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

rᵤ = peak response of any bendroflumethiazide related unspecified degradation product from the Sample solution

rₛ = peak response of bendroflumethiazide from the Standard solution

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

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

Acceptance criteria: See Table 2. The reporting threshold is 0.05%.

Table 2

ᵃ Total impurities include the sum of all nadolol related unspecified degradation products (see Table 1), 2,4-disulfamyl-5-trifluoromethylaniline, and all bendroflumethiazide related unspecified degradation products.

6 ADDITIONAL REQUIREMENTS

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Packaging and Storage: Preserve in tight, light-resistant containers. Store at controlled room temperature.

USP Reference Standards 〈11〉

USP Bendroflumethiazide RS

USP 2.4-Disulfamyl-5-trifluoromethylaniline RS   C₇H₈F₃N₂O₄S₂   319.29

USP Nadolol RS