Ondansetron 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

Ondansetron Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of ondansetron (C₁₈H₁₉N₃O), calculated on the anhydrous basis.

Prepare Ondansetron Compounded Oral Suspension containing 1.0 mg/mL of ondansetron hydrochloride (dihydrate) equivalent to 0.8 mg/mL of ondansetron as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

Ondansetron (as ondansetron hydrochloride dihydrate) 80 mg (100 mg)

Vehicle: a 1:1 mixture of Vehicle for Oral Solution (regular or sugar-free), NF, and Vehicle for Oral Suspension, NF, a sufficient quantity to make 100 mL

Place the required number of tablets in a suitable glass mortar, and comminute to a fine powder, or add Ondansetron hydrochloride powder. Add 50 mL of the Vehicle in 5-mL portions, and mix well with each addition. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add sufficient Vehicle to bring the preparation to final volume, and mix well.

2 ASSAY

Procedure

Mobile phase: 43 mM of monobasic potassium phosphate buffer adjusted with a mixture of 1 N sodium hydroxide and acetonitrile (85:15) to a pH of 5.4

Standard solution: Dissolve USP Ondansetron Hydrochloride RS in Mobile phase to obtain a solution with a nominal concentration of 4 µg/mL of ondansetron.

Sample solution: Bring each bottle of Oral Suspension to room temperature. Pipet 500 µL of Oral Suspension from each bottle into a 100-mL volumetric flask, and dilute with Mobile phase to volume. Pass through a filter of 0.45-µm pore size, and keep frozen at −70° until assayed.

Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 216 nm

Columns

Guard: 3.9-mm × 20-cm; 4-µm packing L10

Analytical: 4.6-mm × 25-cm; 5-µm packing L10

Flow rate: 1 mL/min

Injection volume: 80 µL

System suitability

Sample: Standard solution

[Note—The retention time for ondansetron is about 30 min.]

Suitability requirements

Relative standard deviation: NMT 1.6% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of ondansetron (C₁₈H₁₉N₃O) in the portion of Oral Suspension taken:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = peak response from the Sample solution

rₛ = peak response from the Standard solution

Cₛ = concentration of ondansetron in the Standard solution (µg/mL)

Cᵤ = nominal concentration of ondansetron in the Sample solution (µg/mL)

Acceptance criteria: 90.0%–110.0% on the anhydrous basis

3 SPECIFIC TESTS

pH 〈791〉: 3.6–4.6

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 42 days after the date on which it was compounded when stored at controlled room temperature or in a refrigerator.

Labeling: Label it to state that it is to be well shaken before use, and to state the Beyond-Use Date. Label to indicate that it contains 0.8 mg/mL of ondansetron equivalent to 1 mg/mL of ondansetron hydrochloride (dihydrate).

USP Reference Standards 〈11〉

USP Ondansetron Hydrochloride RS