Allopurinol 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

Change to read:

Allopurinol Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of allopurinol (C₅H₄N₄O). 5 4 4

Prepare Allopurinol Compounded Oral Suspension 20 mg/mL in Vehicle for Oral Suspension and Vehicle for Oral Solution (USP 1-May-2020) as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

Select the number of tablets that contain the specied amount of allopurinol, and calculate the quantity of each ingredient required for the total amount to be prepared. Count, weigh, or measure each ingredient. Thoroughly pulverize the tablets. Mix the powdered Allopurinol tablets and Glycerin to form a smooth paste. Incorporate in (USP 1-May-2020) Vehicle for Oral Suspensionand Vehicle for Oral Solution. (USP 1-May 2020) Add sucient Vehicle for Oral Solution to volume, and mix well. Adjust the pH, if necessary. Package and label.

Prepare Allopurinol Compounded Oral Suspension 20 mg/mL in SyrSpend SF PH4 as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉):

^a Fagron, St. Paul, MN.

Transfer the Allopurinol powder into a suitable container and triturate to form a ne powder. Wet the powder with a small amount of SyrSpend SF PH4, and triturate to make a smooth paste. Add increasing volumes of SyrSpend SF PH4 to make the contents pourable. Transfer contents stepwise and quantitatively to a calibrated container using the remainder of SyrSpend SF PH4. Add sucient SyrSpend SF PH4 to bring to nal volume, and mix well. (USP 1-May-2020)

2 ASSAY

Add the following:

Oral Suspension in SyrSpend SF PH4

Mobile phase: 0.05 M solution of monobasic ammonium phosphate

Standard solution: 0.02 mg/mL of USP Allopurinol RS in acetonitrile

Sample solution: Transfer 1.0 mL of Oral Suspension into a 1000-mL volumetric ask and dilute with acetonitrile to nal volume. Mix well. Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 254 nm

Columns

Guard: 4.0-mm × 3.0-mm; 5-µm packing L1

Analytical: 4.0-mm × 30-cm; 5-µm packing L1

Flow rate: 1.5 mL/min

Injection volume: 20 µL

Sample: Standard solution

[Note—The retention time for allopurinol is about 6.5 min.]

Suitability requirements

Tailing factor: NMT 2.0

Relative standard deviation: NMT 2.0% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of allopurinol (C₅H₄N₄O) in the portion of Oral Suspension taken:

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

r_U = peak response of allopurinol from the Sample solution

r_S = peak response of allopurinol from the Standard solution

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

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

Acceptance criteria: 90.0%–110.0% (USP 1-May-2020)

3 SPECIFIC TESTS

Change to read:

pH 〈791〉

Oral Suspension in Vehicle for Oral Suspension and Vehicle for Oral Solution: (USP 1-May-2020) 6.5–7.5

Oral Suspension in SyrSpend SF PH4: 3.5–4.5 (USP 1-May-2020)

ADDITIONAL REQUIREMENTS

Change to read:

Packaging and Storage: Package in tight, light-resistant containers. Store the Oral Suspension in Vehicle for Oral Suspension and Vehicle for Oral Solution at controlled room temperature. Store the Oral Suspension in SyrSpend SF PH4 at controlled room temperature or in a refrigerator. (USP 1-May-2020)

Change to read:

Beyond-Use Date

Oral Suspension in Vehicle for Oral Suspension and Vehicle for Oral Solution: (USP 1-May-2020) NMT 60 days after the date on which it was compounded when stored at controlled room temperature

Oral Suspension in SyrSpend SF PH4: NMT 90 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator (USP 1-May-2020)

Labeling: Label it to state that it is to be shaken well before use, and to state the Beyond-Use Date.

Add the following: USP Reference Standards 〈11〉

USP Allopurinol RS (USP 1-May-2020)