Development and Validation of a Single Stability-Indicating Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) Method for Identification and Assay of Eprinomectin in Two Different Commercial Injectable Drug Products for Cattle.

Background: Eprinomectin (EPRN) is a semi-synthetic macrocyclic lactone exhibiting antiparasitic activity and is widely used as an active pharmaceutical ingredient (API) in veterinary drug products.

Objective: This study aimed to develop a single stability-indicating reversed-phase (RP)-HPLC method to identify and assay EPRN in two different injectable drug products for cattle.

Methods: The RP-HPLC method is carried out on a Halo-C18 column (100 mm × 4.6 mm id, 2.7 µm particle size) maintained at 55°C. The analytes are separated by a gradient elution at a flow rate of 0.8 mL/min and detected at a wavelength of 245 nm. The mobile phase-A (MPA) of the method is 0.1% (v/v) aqueous perchloric acid, and mobile phase-B (MPB) is ethanol (EtOH). The Ascentis Express C18 column (100 mm × 4.6 mm id, 2.7 µm particle size) was identified and validated as an equivalent column for the prescribed method.

Results: The RP-HPLC method described in this article can adequately separate all major related substances of EPRN in the two drug products from EPRN B1a and EPRN B1b within 20 min.

Conclusion: The developed RP-HPLC method for the identification and assay of EPRN was successfully validated in accordance with the guidelines outlined in the International Conference on Harmonization (ICH) Q2(R2), and demonstrated to be robust, linear, accurate, precise, specific, and stability-indicating.

Highlights: The new RP-HPLC method exhibits a higher level of selectivity but is yet rapid and simple, making it suitable for routine and non-routine analysis in research and QC laboratories.