Meprobamate Tablets

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

Meprobamate Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of meprobamate (C₉H₁₈N₂O₄).

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K (CN 1-May-2020)

Sample: A portion of finely powdered Tablets, equivalent to 800 mg of meprobamate

Analysis: To the Sample add 5 mL of dehydrated alcohol, and heat to just below boiling for about 5 min, with occasional swirling. Cool, and filter into 15 mL of solvent hexane. With the aid of suction, filter the crystals that form, and dry at 60°.

Acceptance criteria: The IR absorption spectrum of a potassium bromide dispersion (about 1 mg in 200 mg) from a portion of crystals obtained from the Sample exhibits maxima only at the same wavelengths as that of a similar preparation of USP Meprobamate RS. If a difference appears, dissolve portions of both the Sample and the Reference Standard in acetone at a concentration of 8 mg/mL. Dilute 0.1-mL portions of the acetone solutions with 1 mL of n-heptane, and remove the solvents by evaporation under nitrogen at a temperature of about 30°. Dry the residues under vacuum at room temperature for 30 min, and repeat the test on the residues.

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

Procedure

Mobile phase: Acetonitrile and water (30:70)

Phenacetin stock solution: 125 μg/mL of phenacetin in acetonitrile

Phenacetin solution: 25 μg/mL of phenacetin prepared as follows from the Phenacetin stock solution. Pipet a suitable volume of Phenacetin stock solution into a volumetric flask. Add acetonitrile to fill 30% of the final flask volume, and dilute with water to volume.

Standard solution: 5 mg/mL of USP Meprobamate RS prepared as follows. Transfer a suitable amount of the Reference Standard to a suitable volumetric flask. Dissolve in 30% of the final flask volume of acetonitrile, and dilute with water to volume.

System suitability solution: 5 mg/mL of USP Meprobamate RS and 5 μg/mL of phenacetin prepared as follows. Dissolve a weighed amount of USP Meprobamate RS, first in acetonitrile, using 20% final volume. Shake to dissolve. Add a suitable volume of Phenacetin solution, and dilute with water to volume.

Sample solution: Nominally equivalent to 5 mg/mL of meprobamate prepared as follows. Transfer an amount of meprobamate from a portion of finely powdered Tablets (NLT 20) to a suitable volumetric flask. Add acetonitrile to fill 30% of final volume, and shake to dissolve.

Dilute with water to volume, and filter, discarding the first 10 mL of the filtrate.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 200 nm

Column: 3.9–4.6-mm × 25–30-cm; 5-μm packing L1

Flow rate: 1 mL/min

Injection volume: 20 μL

System suitability

Samples: System suitability solution and Standard solution

[Note—The relative retention times for meprobamate and phenacetin are about 0.7 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between the meprobamate and the phenacetin peaks, System suitability solution

Relative standard deviation: NMT 2.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of meprobamate (C₉H₁₈N₂O₄) in the portion of Tablets taken:

Result = (r_U/r_S) × (C_S/C_U) × 100

r_U = peak response of meprobamate from the Sample solution

r_S = peak response of meprobamate from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉

Procedure for a pooled sample

Medium: Deaerated water; 900 mL

Apparatus 1: 100 rpm

Time: 30 min

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

Analysis

Calculate the percentage of the labeled amount of meprobamate (C₉H₁₈N₂O₄) dissolved:

Result = (r_U/r_S) × C_S × V × (1/L) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

V = volume of the Medium, 900 mL

L = label claim (mg/Tablet)

Acceptance criteria: NLT 75% (Q) of the labeled amount of meprobamate (C₉H₁₈N₂O₄) is dissolved.

Uniformity of Dosage Units 〈905〉: Meet the requirements

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in well-closed containers.

USP Reference Standards 〈11〉

USP Meprobamate RS