Acetaminophen Capsules

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 Capsules contain 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: 1 mg/mL of acetaminophen prepared as follows. Triturate from contents of the Capsules in methanol. Filter, and use the clear filtrate.

Chromatographic system

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

Acceptance criteria: Meet 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: Weigh the contents of NLT 20 Capsules, and calculate the average weight of the contents of each Capsule. Mix the combined contents of the Capsules, and transfer a portion, equivalent to 100 mg of acetaminophen, to a 200-mL volumetric flask. Add 100 mL of Mobile phase, shake by mechanical means for 10 min, and dilute with Mobile phase to volume. Transfer 5.0 mL of this solution to a 250-mL volumetric flask, and dilute with Mobile phase to volume. 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.

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 or finer pore size, discarding the first 10 mL of the 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 (C₈H₉NO₂) in the portion of Capsules 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

4.1 DISSOLUTION (711)

Medium: Water; 900 mL

Apparatus 2: 50 rpm

Time: 45 min

Standard solution: A known concentration of USP Acetaminophen RS in Medium

Sample solution: A filtered portion of the solution under test, suitably diluted with Medium to obtain a concentration similar to that of the

Standard solution

Instrumental conditions

Mode: UV

Analytical wavelength: 249 nm

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of acetaminophen (C₈H₉NO₂) dissolved.

Tolerances: NLT 75% (Q) of the labeled amount of acetaminophen (C₈H₉NO₂) is dissolved.

4.2 UNIFORMITY OF DOSAGE UNITS (905)

Meet the requirements

5 IMPURITIES

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

6 ADDITIONAL REQUIREMENTS

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

USP REFERENCE STANDARDS (11)

USP Acetaminophen RS