Naproxen Compounded 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)

DOWNLOAD PDF HERE

1 DEFINITION

Naproxen Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of naproxen (C₁₄H₁₄O₃). Prepare Naproxen Compounded Oral Suspension containing 25 mg/mL of naproxen as follows (see Pharmaceutical Compounding-Nonsterile Preparations (795)).

^a Naproxen 250-mg tablets, Apotex Inc., Weston, Ontario.

^b Medisca Pharmaceutique Inc., Montréal, Quebec.

Place the Naproxen tablets in a suitable container and comminute to a fine powder. Add the Vehicle in small portions, and triturate to make a smooth paste. Add increasing volumes of the Vehicle to make a liquid that is pourable. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add sufficient Vehicle to bring to final volume, and mix well.

2 ASSAY

Change to read:

PROCEDURE

Buffer: 5 mM solution of ammonium formate, ^▲adjusted with formic acid to a pH of 4 _{▲(USP 1-May-2022)}

Mobile phase: Methanol and Buffer (82:18)

Internal standard solution: 1.0 mg/mL of USP Ranitidine Hydrochloride RS in water

Standard stock solution: 25 mg/mL of USP Naproxen RS in methanol

Standard solution: Transfer 0.1 mL of Standard stock solution to a 100-ml volumetric flask, add 10 mL of the Internal standard solution, and dilute with methanol to volume to obtain a solution containing 0.025 mg/mL of naproxen and 0.1 mg/mL of ranitidine hydrochloride. Pass through a hydrophilic propylene filter of 0.45-µm pore size.

Sample solution: Add 0.2 mL of Oral Suspension to 1.8 mL of methanol and centrifuge at 5200 rpm for 5 min. Transfer 0.1 mL of the supernatant to a 10-mL volumetric flask, add 1 mL of the Internal standard solution, and dilute with methanol to volume to obtain a solution containing 0.025 mg/mL of naproxen and 0.1 mg/mL of ranitidine hydrochloride. Filter.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 232 nm

Columns

Guard: 3.9-mm x 2-cm; packing L1

Analytical: 4.6-mm x 10-cm; 5-µm packing L1

Flow rate: See Table 1.

Table 1

Injection volume: 20 µL

System suitability

Sample: Standard solution

[NOTE-The retention times for ranitidine hydrochloride and naproxen are about 1.4 and 2.4 min, respectively.]

Suitability requirements

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of naproxen (C₁₄H₁₄O₃) in the portion of Oral Suspension taken:

                         Result = (R_U/R_S) × (C_S/C_U) × 100

R_U = peak response ratio of naproxen to the internal standard from the Sample solution

R_S = peak response ratio of naproxen to the internal standard from the Standard solution

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

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

Acceptance criteria: 90.0%-110.0%

3 SPECIFIC TESTS

PH (791): 4.0-5.0

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Package in tight, light-resistant containers. Store at controlled room temperature or in a refrigerator.

BEYOND-USE DATE: NMT 90 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator

LABELING: Label it to state the Beyond-Use Date.

USP REFERENCE STANDARDS (11)

USP Naproxen RS

USP Ranitidine Hydrochloride RS