Butabarbital Sodium 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

Butabarbital Sodium Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of butabarbital sodium (C₁₀H₁₅N₂NaO₃).

2 IDENTIFICATION

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

3 ASSAY

3.1 PROCEDURE

Solution A: Ammonium hydroxide in water (1 in 25)

Internal standard solution: 1.2 mg/mL of secobarbital in chloroform

Standard solution: 0.8 mg/mL of USP Butabarbital RS and 1 mg/mL of secobarbital in chloroform

Sample stock solution: Finely powder NLT 20 Tablets. Transfer a portion of the powder, equivalent to 50 mg of butabarbital sodium, to a 50-mL volumetric flask. Add 35 mL of Solution A, and dilute with water to volume. Filter, if necessary, discarding the first 15 mL of the filtrate, and transfer 25.0 mL of the clear solution to a separator. Add 2 mL of hydrochloric acid, and extract with three 25-mL portions of chloroform. Filter the extracts through about 15 g of anhydrous sodium sulfate that is supported on a funnel by a small pledget of glass wool. Collect the combined filtrate in a 100-mL volumetric flask, and wash the sodium sulfate with 15 mL of chloroform, collecting the washing with the filtrate. Dilute with chloroform to volume.

Sample

solution: Combine 4.0 mL of Sample stock solution with 1.0 mL of Internal standard solution in a suitable container. Reduce the volume to about 1 mL by evaporation, with the aid of a stream of nitrogen, at room temperature.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: GC

Detector: Flame ionization

Column: 4 - mm * 0.9 - m glass; packed with 3% liquid phase G10 support on 80- to 10-mesh S1A

Temperatures

Injection port: 225°

Detector: 225°

Column: 200 ± 10°

Carrier gas: A suitable gas such as dry nitrogen

Flow rate: 60-80 mL/min

Injection volume: 5 µL

System suitability

Sample: Standard solution

[NOTE-The relative retention times for butabarbital and secobarbital are 0.6 and 1.0, respectively.]

Resolution: NLT 2.4 between butabarbital and secobarbital

Tailing factor: NMT 2.0 each for butabarbital and secobarbital

Relative standard deviation: NMT 1.5% for the peak response ratio of butabarbital to the internal standard

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of butabarbital sodium (C₁₀H₁₅N₂NaO₃) in the portion of Tablets taken:

Result = (R_U/R_S) × (C_S/C_U) x (M_r1/M_r2) × 100

R_U = peak response ratio of butabarbital to the internal standard from the Sample solution

R_S = peak response ratio of butabarbital to the internal standard from the Standard solution

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

C_U = nominal concentration of butabarbital sodium in the Sample solution (mg/mL)

M_r1 = molecular weight of butabarbital sodium, 234.23

M_r2 = molecular weight of butabarbital, 212.25 12

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: Water; 900 mL

Apparatus 1: 100 rpm

Time: 45 min

Standard solution: USP Butabarbital RS in Medium

Sample solution: Pass a portion of the solution under test through a suitable filter, and mix with sufficient ammonium hydroxide to provide a concentration of 0.5 N ammonium hydroxide. Dilute with Medium, if necessary.

Instrumental conditions

Mode: UV

Analytical wavelength: 239 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of butabarbital sodium (C₁₀H₁₅N₂NaO₃) dissolved:

Result = (A_U/A_S) × (C_S/C_U) × D × (M_r1/M_r2) × 100

A_U = absorbance of the Sample solution

A_S = absorbance of the Standard solution

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

C_U = nominal concentration of butabarbital sodium in the Sample solution (mg/mL)

D = dilution factor for the Sample solution

M_r1 = molecular weight of butabarbital sodium, 234.23

M_r2 = molecular weight of butabarbital, 212.25

Tolerances: NLT 75% (Q) of the labeled amount of butabarbital sodium (C₁₀H₁₅N₂NaO₃) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905): Meet the requirements

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers, and store at controlled room temperature.

USP REFERENCE STANDARDS (11)

USP Butabarbital RS