Felbamate 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

Felbamate Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of felbamate (C₁₁H₁₄N₂O₄).

2 IDENTIFICATION

Change to read:

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy (CN 1-MAY-2020)

Sample: Transfer a weighed quantity of finely powdered Tablets, equivalent to 12 mg of felbamate, to a centrifuge tube. Add 10 mL of methanol, and mix on a vortex mixer for 3 min. Centrifuge, and transfer 1 mL of the clear supernatant to a mortar with 200 mg of potassium bromide. Evaporate at 105° in an oven for 15 min. Cool the dried residue in a desiccator, and blend by grinding. Prepare a pellet with 100 mg of the dried residue.

Standard: Transfer 1 mL of 1.2 mg/mL of USP Felbamate RS in methanol to a mortar with 200 mg of potassium bromide. Evaporate at 105° in an oven for 15 min. Cool the dried residue in a desiccator, and blend by grinding. Prepare a pellet with 100 mg of the dried residue.

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

Diluent: Methanol and water (80:20)

Mobile phase: Acetonitrile, methanol, and water (126:84:790)

System suitability solution: 0.05 mg/mL of USP Felbamate Related Compound A RS and 0.2 mg/mL of USP Felbamate RS in Mobile phase

Standard stock solution: 2 mg/mL of USP Felbamate RS in Diluent

Standard solution: 0.2 mg/mL of USP Felbamate RS from Standard stock solution in Mobile phase

Sample stock solution: Nominally 2 mg/mL of felbamate from NLT 20 finely powdered Tablets, prepared as follows. Transfer a weighed quantity of the powder to a suitable volumetric flask. Add 50% of the flask volume of the Diluent. Sonicate for 30 min with intermittent shaking. Shake the flask vigorously for NLT 30 min. Dilute with Diluent to volume. Pass a portion through a suitable membrane filter.

Sample solution: 0.2 mg/mL of felbamate from Sample stock solution in Mobile phase

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 210 nm

OFF Column: 4.6-mm × 15-cm; 5-µm packing L1

Column temperature: 30°

Flow rate: 1.8 mL/min

Injection size: 20 µL

Run time: 3 times the retention time of felbamate

3.2 System suitability

Samples: Standard solution and System suitability solution

Suitability requirements

Resolution: NLT 2 between felbamate related compound A and felbamate, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 2%, Standard solution

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of felbamate (C₁₁H₁₄N₂O₄) in the portion of the Tablets taken:

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

r_U = peak response of felbamate from the Sample solution

r_S = peak response of felbamate from the Standard solution s

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

C_U = nominal concentration of felbamate 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

Mobile phase: Prepare as directed in the Assay.

Standard solution: (L/1000) mg/mL of USP Felbamate RS, where L is the Tablet label claim, in mg. Transfer a suitable weighed quantity of USP Felbamate RS to a suitable volumetric flask. Add 10% of the flask volume of methanol, and sonicate for 5 min to dissolve. Dilute with Medium to volume.

Sample solution: Pass a portion of the solution under test through a suitable filter.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.0-mm x 15-cm; 5-µm packing L1

Flow rate: 2 mL/min

Injection size: 50 µL

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 2%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of felbamate (C₁₁H₁₄N₂O₄) dissolved:

Result = (r_U/r_S) x (C_S/L) x V x 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

L = label claim (mg/Tablet)

V = volume of Medium, 900 mL

Tolerances: NLT 65% (Q) of the labeled amount of felbamate (C₁₁H₁₄N₂O₄) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

ORGANIC IMPURITIES

Diluent, Mobile phase, Sample solution, and Chromatographic system: Proceed as directed in the Assay

System suitability stock solution: 0.4 mg/mL of USP Felbamate Related Compound A RS and 0.6 mg/mL of USP Felbamate RS in Diluent

System suitability solution: 0.4 µg/mL of USP Felbamate Related Compound A RS and 0.6 µg/mL of USP Felbamate RS from System suitability stock solution in Mobile phase

Standard stock solution: 0.6 mg/mL of USP Felbamate RS in Diluent

Standard solution: 0.6 µg/mL of USP Felbamate RS from Standard stock solution in Mobile phase

System suitability

Samples: System suitability solution and Standard solution

Suitability requirements

Resolution: NLT 2 between felbamate related compound A and felbamate, System suitability solution

Tailing factor: NMT 2.0, Standard solution

Relative standard deviation: NMT 10%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Identify the impurities using the relative retention times shown in Table 1. Calculate the percentage of each impurity in the portion of Tablets taken:

Result = (r_U/r_S) x (C_S/C_U) × (1/F) × 100

r_U = peak response of each impurity from Sample solution

r_S = peak response of felbamate from the Standard solution s

C_S = concentration of USP Felbamate RS in the Standard solution (µg/mL)

C_U = nominal concentration of felbamate in the Sample solution (µg/mL)

F = relative response factor (see Table 1)

Acceptance criteria: See Table 1.

Table 1

^a 2-Phenylpropane-1,3-diol.

^b 3-Hydroxy-2-phenylpropyl carbamate.

^c 3-Carbamoyloxy-2-phenylpropyl allophanate.

^d Phenylethyl carbamate. No limit. This is a process impurity.

6 ADDITIONAL REQUIREMENTS

6.1 PACKAGING AND STORAGE

Preserve in well-closed containers, and store at controlled room temperature.

6.2 USP REFERENCE STANDARDS (11).

USP Felbamate RS

USP Felbamate Related Compound A RS

3-Hydroxy-2-phenylpropyl carbamate.

C₁₀H₁₃NO₃ 195.22