Aspirin Delayed-Release Tablets

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

Aspirin Delayed-Release Tablets contain NLT 95.0% and NMT 105.0% of the labeled amount of aspirin (C₉H₈O₄).

2 IDENTIFICATION

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

Change to read:

B. SPECTROSCOPIC IDENTIFICATION TESTS (197), Infrared Spectroscopy: 197K _{(CN 1-MAY-2020)}

Sample: Shake a quantity of finely powdered Tablets, equivalent to about 500 mg of aspirin, with 10 ml, of alcohol for several minutes. Centrifuge the mixture. Pour off the clear supernatant, and evaporate it to dryness. Dry the residue under vacuum at 60 for 1 h.

Acceptance criteria: Meet the requirements

3 ASSAY

PROCEDURE

Mobile phase: 2 g/L of sodium 1-heptanesulfonate in a mixture of acetonitrile and water (15:85). Adjust with glacial acetic acid to a pH of 3.4.

Diluent: Acetonitrile and formic acid (99:1)

Standard solution: 0.5 mg/mL of USP Aspirin RS in Diluent

Sample stock solution: Nominally 5 mg/mL of aspirin prepared as follows. Transfer a quantity equivalent to about 100 mg of aspirin from NLT 20 finely powdered Tablets to a suitable container. Add 20.0 mL of Diluent and 10 glass beads. Shake vigorously for 10 min, and centrifuge.

Sample solution: Nominally 0.5 mg/mL of aspirin in Diluent from Sample stock solution

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 280 nm

Column: 4.0-mm x 30-cm; packing L1

Flow rate: 2 mL/min

Injection volume: 10 µL

System suitability

Sample: Standard solution

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0%

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of aspirin (C₉H₈O₄) in the portion of Tablets taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of aspirin from the Sample solution

r_s = peak response of aspirin from the Standard solution

C_s = concentration of USP Aspirin RS in the Standard solution (mg/mL)

C_u = nominal concentration of aspirin in the Sample solution (mg/mL)

Acceptance criteria: 95.0%–105.0%

4 PERFORMANCE TESTS

Dissolution 〈711〉, Procedure, Apparatus 1 and Apparatus 2, Delayed-Release Dosage Forms, Method B Procedure

Apparatus 1: 100 rpm

Times

Acid stage: 2 h

Buffer stage: 90 min

Diluent: 0.1 N hydrochloric acid and 0.20 M tribasic sodium phosphate (3:1). Adjust, if necessary, with 2 N hydrochloric acid or 2 N sodium hydroxide to a pH of 6.8 ± 0.05.

Standard solution: USP Aspirin RS of a known concentration in 0.1 N hydrochloric acid (for analyzing the Acid stage) and in Diluent (for analyzing the Buffer stage)

Sample solution: Pass a portion of the solution under test through a suitable filter, diluted, if necessary, with 0.1 N hydrochloric acid (for analyzing the Acid stage) and with Diluent (for analyzing the Buffer stage).

Instrumental conditions

Mode: UV

Analytical wavelengths

Acid stage: 280 nm

Buffer stage: 265 nm

Analysis

Samples: Standard solution and Sample solution

Determine the percentage of the labeled amount of aspirin (C₉H₈O₄) dissolved by determining UV absorbances at the isosbestic point of aspirin and salicylic acid (about 280 nm in the Acid stage, and about 265 nm in the Buffer stage).

Tolerances

Acid stage: NMT 10% (Q) of the labeled amount of aspirin (C₉H₈O₄) is dissolved.

Buffer stage: NLT 75% (Q) of the labeled amount of aspirin (C₉H₈O₄) is dissolved.

UNIFORMITY OF DOSAGE UNITS (905): Meet the requirements

5 IMPURITIES

LIMIT OF FREE SALICYLIC ACID

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

System suitability solution: 0.015 mg/mL of USP Salicylic Acid RS and 0.5 mg/mL of USP Aspirin RS in Diluent

Standard solution: 0.015 mg/mL of USP Salicylic Acid RS in Diluent

Sample solution: Use the Sample stock solution from the Assay.

System suitability

Samples: System suitability solution and Standard solution

[NOTE-The relative retention times for salicylic acid and aspirin are about 0.7 and 1.0, respectively.]

Suitability requirements

Resolution: NLT 2.0 between salicylic acid and aspirin, System suitability solution

Relative standard deviation: NMT 4.0%, Standard solution

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of salicylic acid (C₇H₆O₃) in the portion of Tablets taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of salicylic acid from the Sample solution

r_s = peak response of salicylic acid from the Standard solution

C_s = concentration of USP Salicylic Acid RS in the Standard solution (mg/mL)

C_u = nominal concentration of aspirin in the Sample solution (mg/mL)

Acceptance criteria: NMT 3.0%

6 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Aspirin RS

USP Salicylic Acid RS