Phendimetrazine Tartrate 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

Phendimetrazine Tartrate Tablets contain NLT 90.0% and NMT 110.0% of the labeled amount of phendimetrazine tartrate (C₁₂H₁₇NO·C₄H₆O₆).

2 IDENTIFICATION

A.

Analysis: Shake a quantity of finely powdered Tablets, nominally equivalent to 300 mg of phendimetrazine tartrate, with 50 mL of water. Filter, and transfer the filtrate to a 200-mL separator. Add 3 mL of 12.5 N sodium hydroxide, and extract with two 50-mL portions of chloroform. Extract the combined chloroform extracts in a 250-mL separator with two 15-mL portions of 0.5 N hydrochloric acid, and evaporate the combined aqueous extracts on a steam bath to dryness. Dissolve the residue in 5 mL of acetone, and add 50 mL of anhydrous ether to the solution. On standing, phendimetrazine hydrochloride crystallizes out. Filter the precipitate, wash with anhydrous ether, and dry at 105°.

Acceptance criteria: The phendimetrazine hydrochloride crystals so obtained melt at 189°-193°, but the range between the beginning and end of melting does not exceed 2°.

B. IDENTIFICATION TESTS-GENERAL, Tartrate (191)

3 ASSAY

3.1 PROCEDURE

Mobile phase: Dissolve 1.1 g of sodium 1-heptanesulfonate in 575 mL of water, add 400 mL of methanol and 25 mL of dilute acetic acid (14 in 100), and mix. Adjust with glacial acetic acid to a pH of 3.0 ± 0.1, if necessary. Pass through a membrane filter of 0.45-µm pore size, and degas.

Diluent: Dilute acetic acid (14 in 100), methanol, and water (2.5:40:57.5)

Internal standard solution: 0.1 mg/mL of salicylamide in Diluent

Standard solution: 0.7 mg/mL of USP Phendimetrazine Tartrate RS in Internal standard solution

Sample solution: Transfer a portion of finely powdered Tablets from NLT 20 Tablets, nominally equivalent to 35 mg of phendimetrazine tartrate, to a 50-mL volumetric flask. Add 25 mL of Internal standard solution, and sonicate for 15 min. Cool the solution to room temperature, dilute with Internal standard solution to volume, mix, and pass through a membrane filter of 0.45-µm pore size.

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 256 nm

Column: 3.9-mm x 30-cm; packing L1

Flow rate: 1 mL/min

Injection volume: 20 µL

3.3 System suitability

Sample: Standard solution

[NOTE-The relative retention times for salicylamide and phendimetrazine tartrate are 0.5 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 3.0 between the analyte and internal standard peaks

Relative standard deviation: NMT 1.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of phendimetrazine tartrate (C₁₂H₁₇NO·C₄H₆O₆) in the portion of Tablets taken:

Result = (R_U/R_S) x (C_S/C_U) x 100

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

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

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

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

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

4.1 DISSOLUTION (711)

Medium: Water; 900 mL

Apparatus 1: 100 rpm

Time: 60 min

Solution A: 0.025 M monobasic potassium phosphate solution. Adjust with 1 N potassium hydroxide to a pH of 7.5.

Mobile phase: Acetonitrile and Solution A (65:35). Filter and degas.

Standard solution: USP Phendimetrazine Tartrate RS, similarly prepared as the Sample solution

Sample solution: Filter a portion of the solution under test.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 210 nm

Column: 4-mm x 15-cm; packing L15

Flow rate: 1.0 mL/min

Injection volume: 50 µL

System suitability

Sample: Standard solution

Suitability requirements

Relative standard deviation: NMT 3.0% from three replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of phendimetrazine tartrate (C₁₂H₁₇NO·C₄H₆O₆) dissolved in comparison with the Standard solution.

Tolerances: NLT 70% (Q) of the labeled amount of phendimetrazine tartrate (C₁₂H₁₇NO·C₄H₆O₆) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 ADDITIONAL REQUIREMENTS

5.1 PACKAGING AND STORAGE

Preserve in well-closed containers.

5.2 USP REFERENCE STANDARDS (11)

USP Phendimetrazine Tartrate RS