Pemetrexed for Injection

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

Pemetrexed for Injection is a sterile, lyophilized mixture of pemetrexed disodium and suitable added substances. It contains NLT 90.0% and NMT 110.0% of the labeled amount of pemetrexed (C₂₀H₂₁N₅O₆).

[Caution - Handle pemetrexed disodium with great care as it alters genetic material and may be irritating to the eyes and skin.]

2 IDENTIFICATION

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

B. The UV spectrum of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Change to read:

Procedure

Buffer: 0.17% (v/v) glacial acetic acid in water. Adjust with a 50% sodium hydroxide solution to a pH of 5.3.

Mobile phase: Acetonitrile and Buffer (11:89)

Standard solution: 0.14 mg/mL of USP Pemetrexed Disodium RS in water

Sample solution: Nominally equivalent to 0.1 mg/mL of pemetrexed in water, prepared from a composite of at least three vials of Pemetrexed for Injection

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 285 nm or diode array. [Note—Use a diode array detector to perform Identification B.]

Column: 4.6-mm × 7.5-cm; 3.5-μm packing L7

Column temperature: 30°

Flow rate: 1 mL/min

Injection volume: 20 μL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 1.5%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of pemetrexed (C₂₀H₂₁N₅O₆) in the portion of Pemetrexed for Injection taken:

Result = (r_U/r_S) × (C_S/C_U) × (M_r1/M_r2) × 100

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

M_r1 = molecular weight of pemetrexed, 427.42

M_r2 = molecular weight of pemetrexed disodium (anhydrous), 471.38 (ERR 1-May-2018)

Acceptance criteria: 90.0%–110.0%

4 PERFORMANCE TESTS

Uniformity of Dosage Units 〈905〉, Weight Variation: Meets the requirements

5 IMPURITIES

Organic Impurities

Buffer: 0.17% (v/v) glacial acetic acid in water. Adjust with a 50% sodium hydroxide solution to a pH of 5.5.

Solution A: Acetonitrile and Buffer (3:97)

Solution B: Acetonitrile and Buffer (12.5:87.5)

Mobile phase: See Table 1. [Note—After each injection, re-equilibrate the chromatographic system at the initial condition for a minimum of 8 min.]

Table 1

System suitability stock solution: 2.8 mg/mL of USP Pemetrexed Disodium RS prepared as follows. Transfer USP Pemetrexed Disodium RS to a suitable volumetric flask and add a 3% Hydrogen peroxide solution equivalent to 10% of the final volume. Dilute with water to volume.

Mix and heat this solution at 75° for 2–5 h and allow it to come to room temperature. [Note - The solution preparation forms ketopemetrexed, pemetrexed R-dimer, and pemetrexed S-dimer. Pemetrexed R-dimer: (2S,2′S)-2,2′-{[(R)-2,2′-Diamino-4,4′,6-trioxo-1,4,4′,6,7,7′- hexahydro-1′H,5H-5,6′-bipyrrolo[2,3-d]pyrimidine-5,5′-diyl]bis(ethylenebenzene-4,1-diylcarbonylimino)}diglutaric acid. Pemetrexed S-dimer: (2S,2′S)-2,2′-{[(S)-2,2′-Diamino-4,4′,6-trioxo-1,4,4′,6,7,7′-hexahydro-1′H,5H-5,6′-bipyrrolo[2,3-d]pyrimidine-5,5′-diyl]bis(ethylenebenzene-4,1 diylcarbonylimino)}diglutaric acid.]

System suitability solution: Transfer 5 mL of the System suitability stock solution to a 50-mL volumetric flask and dilute with water to volume.

Sensitivity solution: 0.14 μg/mL of USP Pemetrexed Disodium RS in water

Sample solution: Nominally equivalent to 0.2 mg/mL of pemetrexed in water, prepared from 1 vial of Pemetrexed for Injection

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 250 nm

Column: 4.6-mm × 15-cm; 3.5-μm packing L7

Temperatures

Autosampler: 2°–8°

Column: 35°

Flow rate: 1 mL/min

Injection volume: 20 μL

System suitability

Samples: System suitability solution and Sensitivity solution

[Note - The relative retention times for the pemetrexed R-dimer and pemetrexed S-dimer peaks are 0.67 and 0.71, respectively.]

Suitability requirements

Resolution: NLT 2.0 between the pemetrexed R-dimer and pemetrexed S-dimer peaks, System suitability solution

Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Sample: Sample solution

Calculate the percentage of each impurity in the portion of Pemetrexed for Injection taken:

Result = (r_U/r_T) × (1/F) × 100

r_U = peak area of each impurity from the Sample solution

r_T = total peak areas from the Sample solution

F = relative response factor for each individual impurity (see Table 2)

Acceptance criteria: See Table 2. Disregard any peak less than 0.05%.

Table 2

^a (4-{2-[(RS)-2-Amino-4,6-dioxo-4,5,6,7-tetrahydro-3H-pyrrolo[2,3-d]pyrimidin-5-yl]ethyl}benzoyl)-l-glutamic acid.

6 SPECIFIC TESTS

Bacterial Endotoxins Test 〈85〉: NMT 0.17 USP Endotoxin Units/mg of pemetrexed

Sterility Tests 〈71〉: Meets the requirements

Particulate Matter in Injections 〈788〉: Meets the requirements for small-volume injections

pH 〈791〉

Sample: A constituted solution prepared as directed in the labeling

Acceptance criteria: 6.6–7.8

Other Requirements: Meets the requirements in Injections and Implanted Drug Products 〈1〉

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve as described in Packaging and Storage Requirements 〈659〉, Injection Packaging, Sterile solids packaging. Store at controlled room temperature.

USP Reference Standards 〈11〉

USP Endotoxin RS

USP Pemetrexed Disodium RS