Development and Validation of Chiral Reversed-Phase HPLC Method for the Determination of Enantiomeric Purity of (S)-methoprene

Abstract

A chiral reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the enantiomeric resolution of methoprene, isopropyl (2E,4E)-(R,S)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate, and the determination of enantiomeric purity of the (S)-methoprene, isopropyl (2E,4E)-(S)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate. Separation and identification of methoprene enantiomers were investigated using a chiral selector tris(4-methylbenzoate) on the polysaccharide backbone. Good baseline enantioseparation was achieved on ChiralCel OJ-3R column under RP-HPLC condition consisting of methanol and water in a ratio of 80 and 20 (% v/v) with adjusted to appropriate pH using 0.1% formic acid. The best resolutions were achieved using protic methanol than basic acetonitrile for neutral methoprene chiral analysis. The test concentration used in this study is 0.4 mg mL⁻¹. Resolutions between (S)-methoprene and its enantiomer were above 2. The flow rate and column temperature were 1.0 mL min⁻¹ and 40 °C, respectively. Detection was carried out at 260 nm using a diode-array detector (DAD). Developed method was validated in accordance with ICH guidelines for specificity, limit of detection and limit of quantification, linearity, accuracy, precision, ruggedness, and robustness. The method revealed an excellent linearity (R² = 1) with a low limit of detection (0.0392–0.0456 μg mL⁻¹) and a low limit of quantification (0.1189–0.1382 μg mL⁻¹). Recoveries were within 98.9–99.5%. The proposed method was found to be suitable and accurate for the determination of enantiomeric purity of (S)-methoprene.