Acetaminophen Oral Solution

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

Acetaminophen Oral Solution contains NLT 90.0% and NMT 110.0% of the labeled amount of acetaminophen (C₈H₉NO₂).

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. THIN-LAYER CHROMATOGRAPHIC IDENTIFICATION TEST (201)

Sample solution: Nominally 1 mg/mL of acetaminophen in methanol from the Oral Solution

Chromatographic system

Developing solvent system: Methylene chloride and methanol (4:1)

Acceptance criteria: Meets the requirements

3 ASSAY

3.1 PROCEDURE

Mobile phase: Methanol and water (1:3)

Standard solution: 0.01 mg/mL of USP Acetaminophen RS in Mobile phase

Sample stock solution: Nominally 2 mg/mL in Mobile phase, prepared as follows. Transfer 500 mg of acetaminophen from a measured volume of Oral Solution to a 250-mL volumetric flask, and dilute with Mobile phase to volume.

Sample solution: Nominally 0.01 mg/mL of acetaminophen in Mobile phase from the Sample stock solution. Pass a portion of this solution through a filter of 0.5-µm or finer pore size, discarding the first 10 mL of the filtrate. Use the clear filtrate.

3.2 Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 243 nm

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

Flow rate: 1.5 mL/min

Injection volume: 10 µL

3.3 System suitability

Sample: Standard solution

Suitability requirements

Column efficiency: NLT 1000 theoretical plates

Tailing factor: NMT 2

Relative standard deviation: NMT 2.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acetaminophen (CH,NO₂) in the portion of Oral Solution taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution

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

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

Acceptance criteria: 90.0%-110.0%

4 PERFORMANCE TESTS

DELIVERABLE VOLUME (698): Meets the requirements for oral solutions packaged in multiple-unit containers

UNIFORMITY OF DOSAGE UNITS (905): Meets the requirements for oral solutions packaged in single-unit containers

5 IMPURITIES

4-AMINOPHENOL IN ACETAMINOPHEN-CONTAINING DRUG PRODUCTS (227): Meets the requirements

6 SPECIFIC TESTS

6.1 PH (791)

3.8-6.1

6.2 ALCOHOL DETERMINATION, Method II(611) (if present)

Analysis: Determine by the gas-liquid chromatographic procedure, using acetone as the internal standard.

Acceptance criteria: 90.0%-115.0% of the labeled amount of alcohol (C₂H₂OH)

7 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers, and store at controlled room temperature.

USP REFERENCE STANDARDS (11).

USP Acetaminophen RS