Naloxone Hydrochloride 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

Naloxone Hydrochloride Injection is a sterile, isotonic solution of Naloxone Hydrochloride in Water for Injection. It contains NLT 90.0% and NMT 110.0% of the labeled amount of naloxone hydrochloride (C₁₉H₂₁NO₄ · HCl). It may contain suitable preservatives.

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 absorption spectrum of the naloxone peak of the Sample solution exhibits maxima and minima at the same wavelengths as those of the Standard solution, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Mobile phase: A mixture of 1.36 g of sodium 1-octanesulfonate (anhydrous), 1.0 g of sodium chloride, 580 mL of water, 420 mL of methanol, and 1.0 mL of phosphoric acid.

Diluent: Transfer 150 mg of edetate disodium to a 2000-mL volumetric flask, and add 0.9 mL of hydrochloric acid. Dilute with water to volume, and mix.

Standard solution: 10 µg/mL of USP Naloxone RS in Diluent.

Sample solution: Nominally 10 µg/mL of naloxone hydrochloride prepared as follows. Transfer an adequate volume from NLT 5 Injections to a suitable volumetric flask. Dilute with Diluent to volume.

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 229 nm. For Identification B, use a diode array detector in the range of 200–400 nm.
• Column: 4.6-mm × 25-cm; 5-µm packing L1
• Flow rate: 1 mL/min
• Injection volume: 100 µL

System suitability

• Sample: Standard solution
• Suitability requirements:
• Tailing factor: NMT 1.5
• Relative standard deviation: NMT 1.5%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of naloxone hydrochloride (C₁₉H₂₁NO₄ · HCl) in the portion of Injection taken:

Result = (r_u/r_s) × (C_s/C_u) × (M_r1/M_r2) × 100

r_u = peak area of naloxone from the Sample solution

r_s = peak area of naloxone from the Standard solution

C_s = concentration of USP Naloxone RS in the Standard solution (µg/mL)

C_u = nominal concentration of naloxone hydrochloride in the Sample solution (µg/mL)

M_r1 = molecular weight of naloxone hydrochloride (anhydrous), 363.84

M_r2 = molecular weight of naloxone (anhydrous), 327.38

Acceptance criteria: 90.0%–110.0%

4 IMPURITIES

Change to read:

4.1 Limit of 2,2′-Bisnaloxone

Standard solution A: Prepare as directed for the Standard solution in the Assay.

Mobile phase, Diluent, Chromatographic system, and System suitability: Proceed as directed in the Assay by using Standard solution A in place of the Standard solution.

Standard solution B: 0.2 µg/mL of USP Naloxone RS in Diluent from Standard solution A.

Ferric chloride solution: 4% (v/v) ferric chloride TS in water.

Peak identification solution: Dissolve 10 mg of naloxone in 100 mL of 0.1 N hydrochloric acid. Transfer 10.0 mL of the resulting solution to a 100-mL volumetric flask, and add 0.5 mL of the Ferric chloride solution. Heat on a steam bath for 10 min, cool, dilute with water to volume, and mix.

Sample solution: Nominally 10 µg/mL of naloxone hydrochloride prepared as follows. Transfer an adequate volume from NLT 5 Injections to a suitable volumetric flask. Dilute with Diluent to volume.

Analysis

Samples: Standard solution B, Peak identification solution, and Sample solution.

[Note-The relative retention times for naloxone and 2,2′-bisnaloxone (4,5α:4′,5′α-diepoxy-3,3′,14,14′-tetrahydroxy-17,17′-bis(prop-2-enyl)-2,2′-bimorphinanyl-6,6′-dione) are 1.0 and 2.8, respectively.]

Calculate the percentage of 2,2′-bisnaloxone in the portion of Injection taken:

Result = (r_u/r_s) × (C_s/C_u) × (1/F) × (M_r1/M_r2) × 100

r_u = peak area of 2,2′-bisnaloxone from the Sample solution

r_s = peak area of naloxone from Standard solution B

C_s = concentration of USP Naloxone RS in Standard solution B (µg/mL)

C_u = nominal concentration of naloxone hydrochloride in the Sample solution (µg/mL)

F = relative response factor of 2,2′-bisnaloxone to naloxone hydrochloride, 1.8

M_r1 = molecular weight of naloxone hydrochloride (anhydrous), 363.84

M_r2 = molecular weight of naloxone (anhydrous), 327.38

Acceptance criteria: NMT 4.0%

5 SPECIFIC TESTS

pH 〈791〉: 3.0–6.5

Bacterial Endotoxins Test 〈85〉: NMT 500 USP Endotoxin Units/mg of naloxone hydrochloride

Other Requirements: It meets the requirements in Injections and Implanted Drug Products 〈1〉.

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in single-dose or in multiple-dose containers, preferably of Type I glass, protected from light, and store at controlled room temperature.

USP Reference Standards 〈11〉

USP Naloxone RS