Naloxone Hydrochloride

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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C₁₉H₂₁NO₄ · HCl  363.84

Morphinan-6-one, 4,5-epoxy-3,14-dihydroxy-17-(2-propenyl)-, hydrochloride, (5α)-;

17-Allyl-4,5α-epoxy-3,14-dihydroxymorphinan-6-one hydrochloride  CAS RN®: 357-08-4; UNII: F850569PQR

Dihydrate

C₁₉H₂₁NO₄ · HCl · 2H₂O 399.87  CAS RN®: 51481-60-8; UNII: 5Q187997EE

1 DEFINITION

Naloxone Hydrochloride is anhydrous or contains two molecules of water of hydration. It contains NLT 98.0% and NMT 102.0% of naloxone hydrochloride (C₁₉H₂₁NO₄ · HCl), calculated on the dried basis.

2 IDENTIFICATION

Change to read:

2.1 A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197K or 197A

Sample: ▲Dissolve about 150 mg of Naloxone Hydrochloride in 25 mL of water in a small separator and add a few drops of 6 N ammonium hydroxide slowly until no more white precipitate is formed. Extract with three 5-mL portions of chloroform and pass the extracts through a dry filter, collecting the filtrate in a small flask. Evaporate the filtrate on a steam bath to dryness, and dry the residue at 105° for 1 h.▲ (USP 1-Dec-2022)

Acceptance criteria: Meets the requirements

Add the following:

2.2 B. The retention time of the naloxone peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay.

3 ASSAY

Change to read:

3.1 Procedure

Buffer: 0.005 M sodium 1-octanesulfonate in water. Adjust with 50% (v/v) phosphoric acid solution to a pH of 2.0.

Solution A: Acetonitrile, tetrahydrofuran, and Buffer (20:40:940)

Solution B: Acetonitrile, tetrahydrofuran, and Buffer (170:40:790)

Mobile phase: See Table 1.

Table 1

Standard solution: 0.225 mg/mL of USP Naloxone RS in 0.1 N hydrochloric acid

Sample solution: 0.25 mg/mL of Naloxone Hydrochloride in 0.1 N hydrochloric acid

Chromatographic system

• (See Chromatography 〈621〉, System Suitability.)
• Mode: LC
• Detector: UV 230 nm
• Column: 4.0-mm × 12.5-cm; 5-µm packing L1
• Column temperature: 40°
• Flow rate: 1.5 mL/min
• Injection volume: 20 µL

System suitability

• Sample: Standard solution
• Suitability requirements
• Tailing factor: NMT 2.0
• Relative standard deviation: NMT 0.73%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of naloxone hydrochloride (C₁₉H₂₁NO₄ · HCl) in the portion of Naloxone Hydrochloride taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × (M_r₁/M_r₂) × 100

rᵤ = peak response of naloxone from the Sample solution

rₛ = peak response of naloxone from the Standard solution

Cₛ = concentration of USP Naloxone RS in the Standard solution (mg/mL)

Cᵤ = concentration of Naloxone Hydrochloride in the Sample solution (mg/mL)

M_r₁ = molecular weight of naloxone hydrochloride, 363.84

M_r₂ = molecular weight of naloxone, 327.38

Acceptance criteria: 98.0%–102.0% on the dried basis

4 OTHER COMPONENTS

4.1 Content of Chloride

Sample: About 300 mg

Analysis: Dissolve the Sample in 50 mL of methanol contained in a 125-mL conical flask, and add 5 mL of glacial acetic acid and 2 drops of eosin Y TS. Titrate with 0.1 N silver nitrate VS to a pink endpoint. Each milliliter of 0.1 N silver nitrate is equivalent to 3.545 mg of chloride.

Acceptance criteria: 9.54%–9.94% on the dried basis

5 IMPURITIES

Delete the following:

5.1 Noroxymorphone Hydrochloride [(−)-4,5α-Epoxy-3,14-dihydroxymorphinan-6-one hydrochloride] and Other Impurities

Add the following:

5.2 Limit of Naloxone Related Compound D

Buffer: 1.58 g/L of ammonium hydrogen carbonate in water prepared as follows. Dissolve 1.58 g of ammonium hydrogen carbonate in 950 mL of water, adjust with ammonium hydroxide to a pH of 9.0, and dilute with water to 1000 mL.

Solution A: Acetonitrile and Buffer (20:80)

Solution B: Acetonitrile and Buffer (40:60)

Mobile phase: See Table 2.

Table 2

System suitability solution: 5 mg/mL of USP Naloxone RS and 0.0025 mg/mL of USP Naloxone Related Compound D RS in 0.1 N hydrochloric acid

Standard solution: 0.00125 mg/mL of USP Naloxone Related Compound D RS in 0.1 N hydrochloric acid

Sample solution: 25 mg/mL of Naloxone Hydrochloride in 0.1 N hydrochloric acid

Chromatographic system

• (See Chromatography <621>, System Suitability.)
• Mode: LC
• Detector: UV 210 nm
• Column: 4.6-mm × 25-cm; 5-µm packing L1
• Column temperature: 40°
• Flow rate: 2.0 mL/min
• Injection volume: 10 µL

System suitability

• Samples: System suitability solution and Standard solution
• Suitability requirements
• Tailing factor: NMT 1.8 for naloxone related compound D
• Relative standard deviation: NMT 5.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of naloxone related compound D in the portion of Naloxone Hydrochloride taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × 100

Acceptance criteria: NMT 0.010%

5.3 Organic Impurities

Buffer, Solution A, Solution B, Mobile phase, Standard solution, and Chromatographic system: Proceed as directed in the Assay.

Sensitivity solution: 2.25 µg/mL of USP Naloxone RS in 0.1 N hydrochloric acid

System suitability solution: 4.5 mg/mL of USP Naloxone RS and 0.0245 mg/mL of USP Naloxone Related Compound D RS in 0.1 N hydrochloric acid

Sample solution: 5 mg/mL of Naloxone Hydrochloride in 0.1 N hydrochloric acid

System suitability

• Samples: Standard solution, Sensitivity solution, and System suitability solution
• Suitability requirements
• Peak-to-valley ratio: NLT 2.0, System suitability solution
• Relative standard deviation: NMT 0.73%, Standard solution
• Signal-to-noise ratio: NLT 10, Sensitivity solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity other than naloxone related compound D in the portion of Naloxone Hydrochloride taken:

Result = (rᵤ/rₛ) × (Cₛ/Cᵤ) × (M_r₁/M_r₂) × (1/F) × 100

rᵤ = peak response of each impurity from the Sample solution

rₛ = peak response of naloxone from the Standard solution

Cₛ = concentration of USP Naloxone RS in the Standard solution (mg/mL)

Cᵤ = concentration of Naloxone Hydrochloride in the Sample solution (mg/mL), calculated on the dried basis

M_r₁ = molecular weight of naloxone hydrochloride, 363.84

M_r₂ = molecular weight of naloxone, 327.38

F = relative response factor (see Table 3)

Acceptance criteria: See Table 3. The reporting threshold is 0.05%.

Table 3

ᵃ 4,5α-Epoxy-3,10α,14-trihydroxy-17-(prop-2-enyl)morphinan-6-one.

ᵇ 4,5α-Epoxy-3,14-dihydroxymorphinan-6-one.

ᶜ 4,5α-Epoxy-3,10β,14-trihydroxy-17-(prop-2-enyl)morphinan-6-one.

ᵈ For peak identification only.

ᵉ 4,5α:4',5'α-Diepoxy-3,3',14,14'-tetrahydroxy-17,17'-bis(prop-2-enyl)-2,2'-bimorphinanyl-6,6'-dione.

ᶠ 4,5α-Epoxy-14-hydroxy-17-(prop-2-enyl)-3-(prop-2-enyloxy)morphinan-6-one.

6 SPECIFIC TESTS

6.1 Optical Rotation 〈781S〉, Procedures, Specific Rotation

Sample solution: 25 mg/mL in water

Acceptance criteria: −170° to −181°

6.2 Loss on Drying 〈731〉

Analysis: Dry at 105° to constant weight

Acceptance criteria: NMT 0.5% for the anhydrous form and NMT 11.0% for the hydrous form

7 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers. Store at 25°, with excursions permitted between 15° and 30°.

Change to read:

USP Reference Standards 〈11〉

USP Naloxone RS

Morphinan-6-one, 4,5-epoxy-3,14-dihydroxy-17-(2-propenyl)-, (5α).

C₁₉H₂₁NO₄ 327.38

USP Naloxone Related Compound D RS

4,5α-Epoxy-3,14-dihydroxy-17-(prop-2-enyl)morphinan-7-ene-6-one

C₁₉H₁₉NO₄ 325.36