Acetaminophen Oral Suspension

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 Suspension is a suspension of Acetaminophen in a suitable aqueous vehicle. It contains NLT 90.0% and NMT 110.0% of the labeled amount of acetaminophen (C₈H₉NO₂).

2 IDENTIFICATION

A. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K

Sample: Transfer a volume of Oral Suspension, equivalent to 240 mg of acetaminophen, to a separator. Add 50 mL of ethyl acetate, and shake. Filter the ethyl acetate extract through a funnel containing glass wool and 10 g of anhydrous sodium sulfate, Collect the filtrate in a beaker, and evaporate on a steam bath to dryness. Dry the residue under vacuum over silica gel.

Acceptance criteria: The crystals so obtained meet the requirements.

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

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 0.5 mg/mL of acetaminophen prepared as follows. Transfer 100 mg of acetaminophen from a volume of Oral Suspension, previously well shaken, to a 200-mL volumetric flask. Add 100 mL of Mobile phase, and shake by mechanical means for 10 min. Dilute with Mobile phase to volume.

Sample solution: Nominally 0.01 mg/mL of acetaminophen from the Sample stock solution in Mobile phase. Pass a portion of this solution through a filter of 0.5-µm pore size or finer, 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 2.0

Relative standard deviation: NMT 2.0%

3.4 Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acetaminophen (C₈H₉NO₂) in the portion of Oral Suspension 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 s

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%

Delete the following: (RB November 1, 2021)

4 PERFORMANCE TESTS

4.1 UNIFORMITY OF DOSAGE UNITS (905)

For single-unit containers: Meets the requirements

4.2 DELIVERABLE VOLUME (698)

For multiple-unit containers: Meets the requirements

5 IMPURITIES

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

Delete the following: (RB November 1, 2021)

6 SPECIFIC TESTS

PH (791): 4.0-6.9

7 ADDITIONAL REQUIREMENTS

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

USP REFERENCE STANDARDS (11).

USP Acetaminophen RS

USP 4-Aminophenol RS