SIMULTANEOUS DETERMINATION OF DELAPRIL AND MANIDIPINE IN A PHARMACEUTICAL FORMULATION BY A STABILITY-INDICATING RP-LC METHOD

Simple, precise, and stability-indicating reversed-phase liquid chromatography (RP-LC) method was developed and validated for simultaneous determination of delapril (DEL) and manidipine (MAN) in pharmaceutical dosage form, using the Plackett-Burman experimental design for robustness evaluation. The LC method was carried out on a C8 column (250 mm × 4.6 mm i.d., 5 µm), maintained at 35°C. The mobile-phase consisted of acetonitrile and a solution of triethylamine 0.3% pH 3.0 (adjusted with phosphoric acid) (55:45; v/v), run at a flow rate of 1.2 mL · min−1 and using photodiode array (PDA) detection at 220 nm. The chromatographic separation was obtained within 7 min and was linear in the range of 3–120 µg · mL−1 (r2 = 0.9997) for DEL and 1–40 µg · mL−1 (r2 = 0.9998) for MAN. Validation parameters such as the specificity, linearity, precision, accuracy, and robustness were evaluated, giving results within the acceptable range. Stress studies were carried out and no interference of the degradation products was...