ANALYTICAL METHOD DEVELOPMENT AND VALIDATION FOR (S)-(-)-AMLODIPINE-O, O-DI-P-TOLUOYL-D-TARTRATE BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

A novel, robust, and sensitive high-performance liquid chromatography (HPLC) method was successfully developed and validated for the quantitative determination of (S)-(-)-amlodipine-o, o-di-p-toluoyl-D-tartrate, a crucial chiral intermediate in pharmaceutical synthesis. The analysis was carried out on a reversed-phase C18 column using a mobile phase comprising acetonitrile and phosphate buffer (pH 3.0) in a 60:40 (v/v) ratio, delivered at a flow rate of 1.0 mL/min. Detection was performed at 237 nm using a UV detector. Method validation followed ICH Q2(R1) guidelines and confirmed the approach’s linearity, accuracy, precision, specificity, robustness, and sensitivity. The method exhibited excellent linearity within the concentration range of 0.5–100 µg/mL, with a correlation coefficient (R²) of 0.9998. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.15 µg/mL and 0.45 µg/mL, respectively. Precision results showed a relative standard deviation (RSD) of less than 1.5%, and recovery values ranged between 98.5% and 101.2%, indicating high accuracy. This validated HPLC method is well-suited for routine quality control and stability testing of (S)-(-)-amlodipine-o, o-di-p-toluoyl-D-tartrate in Pharma-ceutical environments.