Diazoxide Oral Suspension

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

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

DOWNLOAD PDF HERE

1 DEFINITION

Diazoxide Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of diazoxide (C₈H₇ClN₂O₂S).

2 IDENTIFICATION

2.1 A. Thin-Layer Chromatographic Identification Test 〈201〉

Sample solution: Equivalent to 1 mg/mL of diazoxide prepared as follows. Place a portion of Oral Suspension equivalent to 50 mg of diazoxide in a 50-mL volumetric flask. Add 30 mL of 0.1 N sodium hydroxide, shake for 30 min, and dilute with 0.1 N sodium hydroxide to volume.

Developing solvent system: Methanol, ethyl acetate, and ammonium hydroxide (40:170:30)

Acceptance criteria: Meets the requirements

2.2 B. The retention time of the Sample solution corresponds to that of the Standard solution, both relative to the Internal standard solution, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Mobile phase: Methanol, glacial acetic acid, and 0.01 M sodium 1-pentanesulfonate (20:1:80)

Diluent: Methanol and water (1:4)

Internal standard solution: 2 mg/mL of Hydrochlorothiazide in methanol

Standard stock solution: 1 mg/mL of USP Diazoxide RS in methanol

Standard solution: 50 µg/mL of USP Diazoxide RS and 40 µg/mL of hydrochlorothiazide prepared as follows. Transfer 5.0 mL of the Standard stock solution to a 100-mL volumetric flask, add 2.0 mL of Internal standard solution, and dilute with Diluent to volume.

Sample stock solution: Transfer an amount equivalent to about 100 mg of diazoxide from freshly mixed Oral Suspension to a 50-mL centrifuge tube. Add 2 mL of water and 35 mL of methanol, shake for 15 min, and centrifuge for 5 min. Transfer the supernatant to a 200-mL volumetric flask. Repeat the extraction process two times, beginning with the addition of 2 mL of water, combine the extracts in the 200-mL volumetric flask, and dilute with methanol to volume.

Sample solution: Transfer 10.0 mL of the Sample stock solution to a 100-mL volumetric flask, add 2.0 mL of Internal standard solution, and dilute with Diluent to volume.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 254 nm
• Column: 3.9-mm × 30-cm; packing L11
• Flow rate: 2 mL/min
• Injection volume: 10 µL

System suitability

• Sample: Standard solution
• [Note-The relative retention times of hydrochlorothiazide and diazoxide are about 0.4 and 1.0, respectively.]
• Suitability requirements
• Resolution: NLT 5 between the diazoxide and hydrochlorothiazide peaks
• Relative standard deviation: NMT 1.5%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of diazoxide (C₈H₇ClN₂O₂S) in the portion of Oral Suspension taken:

Result = (Rᵤ/Rₛ) × (Cₛ/Cᵤ) × 100

Rᵤ = peak response ratio of diazoxide to the internal standard from the Sample solution

Rₛ = peak response ratio of diazoxide to the internal standard from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉: Meets the requirements for Oral Suspension packaged in single-unit containers

Deliverable Volume 〈698〉: Meets the requirements for Oral Suspension packaged in multiple-unit containers

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

USP Reference Standards 〈11〉

USP Diazoxide RS