Levocarnitine 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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1 DEFINITION

Levocarnitine Oral Solution is a solution of levocarnitine in water, and it contains suitable antimicrobial agents. It may contain a suitable flavor. It contains NLT 90.0% and NMT 110.0% of the labeled amount of levocarnitine (C₇H₁₅NO₃ ).

2 IDENTIFICATION

A. The retention time of the major peak of the Sample solution corresponds to that of the Standard solution, both relative to the internal

standard, as obtained in the Assay.

3 ASSAY

3.1 Procedure

Buffer: 0.05 M phosphate buffer, pH 2.4, prepared by mixing 11.5 mL of phosphoric acid, 1900 mL of water, and about 100 mL of 1 N sodium hydroxide

Mobile phase: Dissolve 555 mg of sodium 1-heptanesulfonate in 980 mL of Buffer with stirring. Add 20 mL of methanol, and mix.

Internal standard solution: 0.02 mg/mL of p-aminobenzoic acid in water

Standard solution: Transfer about 10 mg of USP Levocarnitine RS to a 5-mL volumetric flask, add 1.0 mL of the Internal standard solution, and dilute with water to volume.

Sample stock solution: Equivalent to 10 mg/mL of levocarnitine in water from an accurately measured volume of Oral Solution

Sample solution: Wash a 10-mm × 4-cm disposable column containing 500 mg of packing L1, in order, with two column volumes of methylene chloride, two column volumes of methanol, and three column volumes of water. Pipet 5.0 mL of the Sample stock solution into the washed disposable column, and rinse the column twice with 6.0-mL portions of water. Collect the filtrate and washings in a 25-mL volumetric flask, add 5.0 mL of the Internal standard solution, and dilute with water to volume.

3.2 Chromatographic system

(See Chromatography 〈621〉, System Suitability.)

Mode: LC

Detector: UV 225 nm

Column: 3.9-mm × 30-cm; 10-μm packing L1

Flow rate: 1.5 mL/min

Injection size: 40 μL

3.3 System suitability

Sample: Standard solution

[Note—The relative retention times for levocarnitine and p-aminobenzoic acid are 0.56 and 1.0, respectively.]

3.4 Suitability requirements

Resolution: NLT 1.5 between the levocarnitine and internal standard peaks

Relative standard deviation: NMT 2.0% for levocarnitine

Analysis

Samples: Standard solution and Sample solution

Calculate the percentage of the labeled amount of levocarnitine (C₇H₁₅NO₃) in the portion of Oral Solution taken:

Result = (R_U /R_S ) × (C_S /C_U ) × 100

R_U = peak area ratio of levocarnitine to p-aminobenzoic acid from the Sample solution

R_S = peak area ratio of levocarnitine to p-aminobenzoic acid from the Standard solution

C_S = concentration of USP Levocarnitine RS in the Standard solution (mg/mL)

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

Acceptance criteria: 90.0%–110.0%

4 SPECIFIC TESTS

pH 〈791〉: 4.0–6.0

5 ADDITIONAL REQUIREMENTS

Packaging and Storage: Preserve in tight containers.

USP Reference Standards 〈11〉

USP Levocarnitine RS