Ondansetron Oral Solution

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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Ondansetron Oral Solution

Ondansetron Oral Solution is a solution of Ondansetron Hydrochloride in a suitable vehicle. It contains not less than 95.0 percent and not more than 105.0 percent of the labeled amount of ondansetron (C₁₈H₁₉N₃O).

Packaging and storage—**Preserve in well-closed, light-resistant containers.

Change to read:

USP Reference standards 〈11〉—

USP Ondansetron Hydrochloride RS

USP Ondansetron Related Compound A RS

▲3-[(Dimethylamino)methyl]-9-methyl-1,2,3,9-tetrahydro-4H-carbazol-4-one hydrochloride.▲ (ERR 1-Apr-2022)

USP Ondansetron Related Compound C RS

▲9-Methyl-1,2,3,9-tetrahydro-4H-carbazol-4-one.▲ (ERR 1-Apr-2022)

USP Ondansetron Related Compound D RS

▲9-Methyl-3-methylene-1,2,3,9-tetrahydro-4H-carbazol-4-one.▲ (ERR 1-Apr-2022)

1 Identification—

A: Thin-Layer Chromatographic Identification Test 〈201〉—

Test solution—**Dilute a portion of Oral Solution with a mixture of methanol and water (50:50) to obtain a solution containing about 0.2 mg of ondansetron per mL.

Standard solution: 0.25 mg per mL in methanol.

Developing solvent system: chloroform, ethyl acetate, methanol, and ammonium hydroxide (90:50:40:1).

B: The retention time of the major peak in the chromatogram of the Assay preparation corresponds to that in the chromatogram of the Standard preparation, as obtained in the Assay.

Microbial enumeration tests 〈61〉 and Tests for specified microorganisms 〈62〉—

It meets the requirements of the tests for absence of Escherichia coli.

The total aerobic microbial count does not exceed 100 cfu per g, the Enterobacteriaceae count does not exceed 10 cfu per g, and the total combined molds and yeasts count does not exceed 50 cfu per g.

Deliverable volume 〈698〉: meets the requirements.

pH 〈791〉: between 3.3 and 4.0.

Limit of ondansetron related compound D—

Mobile phase—**Proceed as directed in the test for Limit of ondansetron related compound D under Ondansetron Hydrochloride.

System suitability solution—**Dissolve suitable quantities of USP Ondansetron Related Compound D RS and USP Ondansetron Related Compound C RS in Mobile phase; and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution containing about 0.5 µg per mL and 2 µg per mL, respectively.

Standard solution—**Dissolve an accurately weighed quantity of USP Ondansetron Related Compound D RS in Mobile phase; and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.5 µg per mL.

Test solution—**Quantitatively dilute, if necessary, an accurately measured volume of Oral Solution with Mobile phase to obtain a solution containing about 0.8 mg of ondansetron per mL.

Chromatographic system (see Chromatography 〈621〉)—

The liquid chromatograph is equipped with a 328-nm detector and a 4.6-mm × 25-cm column that contains packing L10.

The flow rate is about 1.5 mL per minute.

Chromatograph the System suitability solution, and record the peak responses as directed for Procedure: the resolution, R, between ondansetron related compound D and ondansetron related compound C is not less than 2.0; the tailing factor for ondansetron related compound D is not more than 2.0; and the relative standard deviation for replicate injections is not more than 4.0%.

Procedure—**Separately inject equal volumes (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of ondansetron related compound D in the volume of Oral Solution taken by the formula:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = response of ondansetron related compound D from the Test solution

rₛ = response of ondansetron related compound D from the Standard solution

Cₛ = concentration of USP Ondansetron Related Compound D RS in the Standard solution (µg per mL)

Cᵤ = concentration of ondansetron in the Test solution (µg per mL)

Acceptance criteria: NMT 0.20%

2 Assay—

Mobile phase—**Proceed as directed in the Assay under Ondansetron Hydrochloride.

Standard preparation—**Dissolve an accurately weighed quantity of USP Ondansetron Hydrochloride RS in Mobile phase, and dilute quantitatively, and stepwise if necessary, with Mobile phase to obtain a solution having a known concentration of about 0.08 mg of ondansetron per mL.

Assay preparation—**Quantitatively dilute an accurately measured volume of Oral Solution with Mobile phase to obtain a solution containing about 0.08 mg of ondansetron per mL.

Chromatographic system (see Chromatography 〈621〉)—

The liquid chromatograph is equipped with a 216-nm detector and a 4.6-mm × 25-cm column that contains packing L10.

The flow rate is about 1.5 mL per minute.

Procedure—**Separately inject equal volumes (about 20 µL) of the Standard preparation and the Assay preparation into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the percentage of the labeled amount of ondansetron (C₁₈H₁₉N₃O) in the Oral Solution taken by the formula:

Result = (rᵤ / rₛ) × (Cₛ / Cᵤ) × 100

rᵤ = response of ondansetron from the Assay preparation

rₛ = response of ondansetron from the Standard preparation

Cₛ = concentration of ondansetron in the Standard preparation (mg per mL)

Cᵤ = concentration of ondansetron in the Assay preparation (mg per mL)

Acceptance criteria: 95.0%–105.0%

Other requirements—

Alcohol content: NMT 10% (v/v)

3 Labeling—

Label it to indicate the alcohol content.