Pentazocine

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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C₁₉H₂₇NO     285.42 

2,6-Methano-3-benzazocin-8-ol, 1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(3-methyl-2-butenyl)-, (2α,6α,11R*)-;

(2R*,6R*,11R*)-1,2,3,4,5,6-Hexahydro-6,11-dimethyl-3-(3-methyl-2-butenyl)-2,6-methano-3-benzazocin-8-ol CAS RN®: 359-83-1; UNII:  RP4A60D26L.

1 DEFINITION

Pentazocine contains NLT 98.0% and NMT 102.0% of pentazocine (C₁₉H₂₇NO), calculated on the dried basis. 

2 IDENTIFICATION

Change to read:

A. Spectroscopic Identification Tests 〈197〉, Infrared Spectroscopy: 197A or 197K  (CN 1-May-2020)

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

3 ASSAY

Procedure

Solution A: 15 mM sodium borate in water. Adjust with 10 N sodium hydroxide to a pH of 10.0.

Solution B: Methanol

Mobile phase: See Table 1.

Table 1

Diluent: Methanol, phosphoric acid, and water (500:1:500)

Standard solution: 0.025 mg/mL of USP Pentazocine RS in Diluent

Sample solution: 0.025 mg/mL of Pentazocine in Diluent

3.1 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm

Column: 4.6-mm × 10-cm; 2.6-µm packing L1

Column temperature: 40°

Flow rate: 0.5 mL/min

Injection volume: 20 µL

3.2 System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 0.73%

3.3 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of pentazocine (C₁₉H₂₇NO) in the portion of Pentazocine taken:

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

r_U = peak response of pentazocine from the Sample solution

r_S = peak response of pentazocine from the Standard solution

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

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

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

4 IMPURITIES

Residue on Ignition 〈281〉: NMT 0.2%

Organic Impurities

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

Sensitivity solution: 0.0006 mg/mL of USP Pentazocine RS in Diluent

Standard solution: 0.002 mg/mL of USP Pentazocine RS in Diluent

Sample solution: 2 mg/mL of Pentazocine in Diluent. Sonicate to dissolve, if necessary.

System suitability

Samples: Sensitivity solution and Standard solution

Suitability requirements

Relative standard deviation: NMT 5.0%, Standard solution

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

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of each impurity in the portion of Pentazocine taken:

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

r_U = peak response of each impurity from the Sample solution

r_S = peak response of pentazocine from the Standard solution

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

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

Acceptance criteria: See Table 2. The reporting threshold is 0.03%.

Table 2

a (2R,6R,11R)-1,2,3,4,5,6-Hexahydro-6,11-dimethyl-2,6-methano-3-benzazocin-8-ol.

b (2R,6R,11R)-3-(3-Hydroxy-3-methylbutyl)-6,11-dimethyl-1,2,3,4,5,6-hexahydro-2,6-methanobenzo[d]azocin-8-ol.

5 SPECIFIC TESTS

Bacterial Endotoxins Test 〈85〉: The level of bacterial endotoxins is such that the requirement in the relevant dosage form monograph(s) in which Pentazocine is used can be met. Where the label states that Pentazocine must be subjected to further processing during the preparation of injectable dosage forms, the level of bacterial endotoxins is such that the requirement in the relevant dosage form monograph(s) in which Pentazocine is used can be met.

Loss on Drying 〈731〉

Analysis: Dry at a pressure of NMT 5 mm of mercury at 60° to constant weight.

Acceptance criteria: NMT 1.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight, light-resistant containers.

Labeling: Where Pentazocine must be subjected to further processing during the preparation of injectable dosage forms to ensure acceptable levels of bacterial endotoxins, it is so labeled.

USP Reference Standards 〈11〉

USP Pentazocine RS