QbD-driven RP-HPLC method for the simultaneous analysis of dihydropyridines calcium channel blockers in pharmaceuticals

A rapid, sensitive, and selective reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous determination of five dihydropyridines calcium channel blockers, namely: amlodipine (AML), nifedipine (NIF), lercanidipine (LER), nimodipine (NIM) and nitrendipine (NIT) using Quality by Design approaches (QbD). The chromatographic separation was achieved on Luna C8 (100 × 4.6 mm 3 μm) column using an isocratic mobile phase consisting of acetonitrile-methanol - 0.7% triethylamine pH 3.06 (30-35-35) adjusted with ortho phosphoric acid at a flow rate of 1 mL/min with UV detection at 237 nm. The optimized method demonstrated good chromatographic resolution with average retention times of 2.93, 3.98, 4.98, 6.32 and 7.75 min for AML, NIF, LER, NIT and NIM, respectively. The method was validated according to ICH guidelines, showing linearity in the concentration range of 10-50 µg/mL with correlation coefficients (r²) ≥ 0.9989 for all analytes. The method demonstrated high trueness (99.11-100.09%) and precision (RSD < 1.1%). The validated method was successfully applied for the determination of these drugs in their pharmaceutical formulations, with recovery values ranging from 99.57 to 100.07% and without significant interference from excipients. Greenness and practicality evaluations detected using AGREE, MoGAPI, complex MoGAPI, AGSA, CaFRI, BAGI and CACI tools which were, indicating the method's environmental friendliness and excellent practical applicability for routine pharmaceutical quality control analysis.