Morantel Tartrate

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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C₁₂H₁₆N₂S · C₄H₆O₆          370.42

Pyrimidine, 1,4,5,6-tetrahydro-1-methyl-2-[2-(3-methyl-2-thienyl)ethenyl]-, (E)-,[R-(R*R*)]-2,3-dihydroxybutanedioate (1:1).

(E)-1,4,5,6-Tetrahydro-1-methyl-2-[2-(3-methyl-2-thienyl) vinyl]pyrimidine tartrate (1:1) CAS RN^®: 26155-31-7; UNII: 5WF7E9QC3F.

Morantel CAS RN^®: 20574-50-9; UNII: 7NJ031HAX5.

>> Morantel Tartrate contains not less than 96.4 percent and not more than 101.5 percent of C₁₂H₁₆N₂S · C₄H₆O₆, calculated on the dried basis.

1 Packaging and storage-

Preserve in well-closed, light-resistant containers. Store at 25°, excursions permitted between 15° and 30°.

2 Labeling-

Label it to indicate it is for veterinary use only.

3 USP REFERENCE STANDARDS (11)-

USP Morantel Tartrate RS

Clarity and color of solution-Dissolve and dilute 0.25 g to 25.0 mL in carbon dioxide-free water. The solution is clear and yellow to greenish yellow in color.

3.1 Identification-

Change to read:

A: ^▲Spectroscopic Identification Tests (197), Infrared Spectroscopy: 197K _{▲(CN 1-May-2020).}

B: It meets the requirements of the test for Tartrate (191).

C: The retention time of the morantel peak in the chromatogram of the Test solution corresponds to that in the chromatogram of Standard solution 1, as obtained in the test for Related compounds.

MELTING TEMPERATURE (741): 167° to 172°.

PH (791): between 2.8 and 3.9.

Solution-Dissolve and dilute 0.25 g to 25.0 mL in carbon dioxide-free water.

LOSS ON DRYING (731)-Dry it at 100° to 105" to constant weight: it loses not more than 1.5% of its weight.

RESIDUE ON IGNITION (281): not more than 0.1%.

3.2 Related compounds-

[NOTE-Conduct this test without exposure to daylight, and with the minimum necessary exposure to artificial light.]

Mobile phase-Mix 3.5 mL of triethylamine and 850 mL of water. Adjust with phosphoric acid to a pH of 2.5. Add 50 mL of tetrahydrofuran and 100 mL of methanol, and mix.

Tartrate solution-Prepare a solution containing about 0.15 mg of tartaric acid per mL in Mobile phase.

Standard solution 1-Dissolve an accurately weighed quantity of USP Morantel Tartrate RS in Mobile phase to obtain a solution having a know concentration of about 5.0 µg per mL.

Standard solution 2-Dilute 2.0 mL of Standard solution 1 to 100.0 mL with Mobile phase.

System suitability solution-Expose 10 mL of Standard solution 1 to daylight for 15 minutes before injection.

Test solution-Dissolve an accurately weighed quantity of Morantel Tartrate in Mobile phase to obtain a solution having a concentration of about 0.5 mg per mL.

Chromatographic system (see CHROMATOGRAPHY (621))-The liquid chromatograph is equipped with a 226-nm detector and a 4.6-mm x 25-cm column that contains 5-µm packing L1. The flow rate is about 0.75 mL per minute. Chromatograph the Tartrate solution, Standard solution 1, and the System suitability solution, and record the peak areas as directed for Procedure: using the System suitability solution, the resolution, F between morantel and its preceding peak ((Z)-isomer) is not less than 2. The relative retention times are about 0.8, 1.0, and 1.2 for the morantel (Z)-isomer, morantel, and the morantel 4-methyl isomer (1-methyl-2-[(E)-2-(4-methylthiophen-2-yl)ethenyl)-1,4,5,6 tet rahydropyrimidine), respectively.

Procedure-Separately inject equal volumes (about 20 µL) of the Tartrate solution, Standard solution 1, Standard solution 2, and the Test solution into the chromatograph, record the chromatograms, and measure the areas for the major peaks. Disregarding the tartrate peak and any peak in the chromatogram of the Test solution less than the area of the principal peak in the chromatogram of Standard solution 2, calculate the area percentage of each impurity, relative to morantel, in the portion of Morantel Tartrate taken by the formula:

                         100 (C_S/C_U)(r_i/r_S) 

in which C_S and C_U, are the concentrations of morantel tartrate, in mg per mL, of Standard solution 1 and the Test solution, respectively; and r_i and r_S are the peak areas of each individual impurity and morantel obtained from the Test solution and Standard solution 1, respectively: not more than 3% of the morantel 4-methyl isomer is found; not more than 0.5% of any other individual impurity is found; and not more than 1% of total other individual impurities is found.

3.3 Assay-

Dissolve 0.280 g in 40 mL of anhydrous acetic acid. Titrate with 0.1 N perchloric acid VS, determining the endpoint potentiometrically (see Titrimetry (541)). One mL of 0.1 N perchloric acid is equivalent to 37.04 mg of C₁₂H₁₆N₂S · C₄H₆O₆ .