Atenolol 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

Atenolol Compounded Oral Suspension contains NLT 90.0% and NMT 110.0% of the labeled amount of atenolol (C₁₄H₂₂N₂O₃).

Prepare Atenolol Compounded Oral Suspension 10 mg/mL as follows (see Pharmaceutical Compounding—Nonsterile Preparations 〈795〉).

^a Perrigo Pharmaceuticals, Allegan, MI.

Pour Atenolol powder into a suitable container. Wet the powder with a small amount of Vehicle, and triturate to make a smooth paste. Add Vehicle to make the contents pourable. Transfer contents stepwise and quantitatively to a calibrated container using the remainder of Vehicle. Add sufficient Vehicle to bring to final volume. Shake to mix well.

2 ASSAY

PROCEDURE

Solution A: 25 mM sodium phosphate adjusted with phosphoric acid to a pH of 3.0

Solution B: Water adjusted with phosphoric acid to a pH of 3.0

Solution C: Methanol and Solution B (50:50)

Mobile phase: Acetonitrile and Solution A (15:85). Filter, and degas.

Standard stock solution: 10 mg/mL of USP Atenolol RS in Solution C. Mix well and sonicate for 3 min. Store at 2°-8"

Standard solution: Transfer 2.0 mL of the Standard stock solution to a 500-mL volumetric flask, add 0.5 mL of Solution C, and dilute with Solution B to volume. Mix well. Centrifuge a portion of the resultant solution for 5 min at 14,000 rpm, and use the supernatant. Protect from light, and store at 2°-8°.

Sample solution: Shake each bottle of Oral Suspension thoroughly. Transfer 2.0 mL of Oral Suspension into a 500-mL volumetric flask, and add 0.5 mL of Solution C. Dilute with Solution B to volume. Mix well. Centrifuge a portion of the solution for 5 min at 14,000 rpm, and use the supernatant. Protect from light, and store at 2°-8°.

Chromatographic system

(See Chromatography (621), System Suitability.)

Mode: LC

Detector: UV 227 nm

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

Temperatures

Column: 30°

Autosampler: 5°

Flow rate: 0.7 mL/min

Injection volume: 20 µL

System suitability

Sample: Standard solution

[NOTE-The retention time for atenolol is about 5.1 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 atenolol (C₁₄H₂₂N₂O₃) in the portion of Oral Suspension taken:

Result = (r_u /r_s ) × (C_s /C_u ) × 100

r_u = peak response of atenolol from the Sample solution

r_s = peak response of atenolol from the Standard solution

C_s = concentration of atenolol in the Standard solution (mg/mL)

C_u = nominal concentration of atenolol in the Sample solution (mg/mL)

Acceptance criteria: 90.0%–110.0%

3 SPECIFIC TESTS

pH 〈791〉: 6.4–7.4

4 ADDITIONAL REQUIREMENTS

Packaging and Storage: Package in tight, light-resistant containers. Store at 2°–8° or at controlled room temperature.

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

Beyond-Use Date: NMT 90 days after the date on which it was compounded when stored at 2°–8° or at controlled room temperature

USP Reference Standards 〈11〉

USP Atenolol RS