Metoprolol Tartrate 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)

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1 DEFINITION

Metoprolol Tartrate Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of metoprolol tartrate [(C₁₅H₂₅NO₃)₂ · C₄H₆O₆]

Prepare Metoprolol Tartrate Compounded Oral Suspension 10 mg/mL as follows (see Pharmaceutical Compounding-Nonsterile Preparations (795)).

Place the required number of tablets in a suitable mortar, and comminute to a fine powder, or use Metoprolol Tartrate powder. Add the Vehicle in small portions, and mix well. Transfer the contents of the mortar, stepwise and quantitatively, to a calibrated bottle. Add the Vehicle in portions to rinse the mortar. Add sufficient Vehicle to bring to final volume, and mix well.

2 ASSAY

PROCEDURE

Mobile phase: 961 mg of 1-pentanesulfonic acid sodium salt (monohydrate) and 82 mg of anhydrous sodium acetate in a mixture of 550 mL of methanol and 470 mL of water. Add 0.57 mL of glacial acetic acid. Filter, and degas.

Standard solution: 100 µg/mL of USP Metoprolol Tartrate RS

Sample solution: Agitate the container of Oral Suspension for 30 min on a rotating mixer, remove a 5-mL sample, and store in a clear glass vial at-70 until analyzed. At the time of analysis, remove the sample from the freezer, allow it to reach room temperature, and mix with a vortex mixer for 30 s. Pipet 1.0 mL of the sample to a 100-mL volumetric flask, and dilute with Mobile phase to volume.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 254 nm

Column: 4.6-mm x 25-cm; 5-µm packing L1

Flow rate: 1.0 mL/min

Injection volume: 20 µL

System suitability

Sample: Standard solution

[NOTE-The retention time for metoprolol tartrate is about 7.3 min.]

Suitability requirements

Relative standard deviation: NMT 1.3% for replicate injections

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of metoprolol tartrate [(C₁₅H₂₅NO₃)₂ · C₄H₆O₆] in the portion of Oral Suspension taken:

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

r_U = peak response from the Sample solution

r_S = peak response from the Standard solution 

C_S = concentration of USP Metoprolol Tartrate RS in the Standard solution (µg/mL)

C_U = nominal concentration of metoprolol tartrate in the Sample solution (µg/mL)

Acceptance criteria: 90.0%-110.0%

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 60 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, and to state the Beyond-Use Date.

USP REFERENCE STANDARDS (11)

USP Metoprolol Tartrate RS