Validated RP-HPLC and Chromogenic UV Methods for Quantification of Ranolazine in Bulk, Plasma, and Nanoformulation as...

The study was designed to establish and validate simple, precise, and economical analytical methods for the quantitative determination of Ranolazine in compliance with International Council for Harmonisation Q2(R2) and M10 bioanalytical validation guidelines. The aim was to ensure accurate estimation in both pharmaceutical formulations and biological samples. Quantification was carried out using reverse phase high-performance liquid chromatography (RP-HPLC) and UV-visible spectrophotometry. Chromatographic separation was performed on a Phenomenex C18 (250 mm × 4.6mmID × 5um) column using a mobile phase composed of methanol and water (45:55, pH adjusted to 5.5 with glacial acetic acid). The system operated under isocratic conditions at a flow rate of 1.2 mL/min, with detection at 278 nm and an injection volume of 20 µL. In the spectrophotometric method, ranolazine produced a stable chromogenic complex measurable at the same wavelength. Additionally, a nanoformulation of ranolazine was developed via a microemulsion technique, yielding uniform and stable nanoparticles (∼176 nm). Method validation was performed according to ICH Q2(R2) for analytical parameters such as specificity, linearity, accuracy, precision, robustness, LOD, and LOQ, while bioanalytical validation in plasma followed ICH M10 criteria, including selectivity, recovery, matrix effect, and stability. The methods demonstrated excellent linearity with a correlation coefficient (r²) greater than 0.999 across the concentration range of 22-310 µg/mL. Recovery values ranged from 98.9% to 99.85%, and precision was confirmed with RSD values below 2%. LOD and LOQ were found to be 0.019 and 0.060 µg/mL. Application of the RP-HPLC method to tablet analysis showed an assay value of 99.59% for the 500 mg formulation, confirming accuracy. The nanoformulation exhibited an accurate drug content with an assay value of 99.82% at 80 µg/mL. Furthermore, the extraction efficiency was determined to be 99.56% by liquid-liquid extraction, indicating efficient recovery from biological matrices. The proposed RP-HPLC and chromogenic UV-visible methods were found to be reliable, sensitive, and reproducible for the estimation of Ranolazine. These validated methods are well-suited for routine quality control analysis, stability studies, and bioanalytical applications, including evaluation of advanced drug delivery systems such as nanoformulations.