Clarithromycin for 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 

Clarithromycin for Oral Suspension is a dry mixture of Clarithromycin, dispersing agents, diluents, preservatives, and flavorings. It contains NLT 90.0% and NMT 115.0% of the labeled amount of clarithromycin (C₃₈H₆₉NO₁₃), the labeled amount being 25 mg or 50 mg/mL when constituted as directed in the labeling. 

2 IDENTIFICATION 

A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, as obtained in the Assay. 

3 ASSAY 

Procedure 

Buffer A: 0.067 M monobasic potassium phosphate 

Buffer B: 0.067 M dibasic potassium phosphate 

Mobile phase: Methanol and Buffer A (60:40), adjusted with phosphoric acid to a pH of 3.5. Pass through a suitable filter. Standard stock solution: Equivalent to 2.1 mg/mL of clarithromycin from USP Clarithromycin RS in methanol 

Standard solution: 0.415 mg/mL of clarithromycin from Standard stock solution in Mobile phase 

Sample stock solution: Constitute the Clarithromycin for Oral Suspension as directed in the labeling. Transfer an aliquot of the suspension, equivalent to 1–2 g of clarithromycin, with the aid of 330 mL of Buffer B, to a 1000-mL volumetric flask containing 50 mL of Buffer B. Shake by mechanical means for 30 min, and dilute with methanol to volume. Sonicate for about 30 min, and allow to cool. Dilute with methanol to volume, add a magnetic stirring bar, and stir for 60 min. Allow to settle, and use the clear supernatant. 

Sample solution: Transfer an aliquot of the Sample stock solution, nominally equivalent to 20 mg of clarithromycin, to a 50-mL volumetric flask, dilute with Mobile phase to volume, and pass through a suitable filter. 

Chromatographic system 

(See Chromatography 〈621〉, System Suitability.) 

Mode: LC 

Detector: UV 210 nm 

Columns 

Guard (optional): Packing L1 

Analytical: 4.6-mm × 15-cm; packing L1 

Column temperature: 50° 

Flow rate: 1 mL/min 

Injection volume: 50 µL 

System suitability 

Sample: Standard solution 

Suitability requirements 

Tailing factor: 1.0–1.7 

Relative standard deviation: NMT 2.0% 

Analysis 

Samples: Standard solution and Sample solution 

Calculate the percentage of the labeled amount of clarithromycin (C₃₈H₆₉NO₁₃) in the portion of the constituted Clarithromycin for OralSuspension taken: 

Result = (r_U/r_S) × (C_S/C_U) × 100 

r_U = peak area response from the Sample solution

r_S = peak area response from the Standard solution

C_S = concentration of the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–115.0% 

4 PERFORMANCE TESTS 

Uniformity of Dosage Units 〈905〉(for powder packaged in single-unit containers): Meets the requirements Deliverable Volume 〈698〉(for powder packaged in multiple-unit containers): Meets the requirements 

5 SPECIFIC TESTS 

pH 〈791〉 

Sample: Use the suspension constituted as directed in the labeling. 

Acceptance criteria: 4.0–5.4 

Loss on Drying 〈731〉 

Sample: 1 g 

Analysis: Dry under vacuum at a pressure not exceeding 5 mm of mercury at 60° for 3 h. 

Acceptance criteria: NMT 2.0% 

6 ADDITIONAL REQUIREMENTS 

Packaging and Storage: Preserve in tight containers. 

USP Reference Standards 〈11〉 

USP Clarithromycin RS