Green metric based evaluation of an RP HPLC method for simultaneous quantification of active pharmaceutical ingredient preservative and related impurities in pharmaceutical formulations

A reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed for the simultaneous determination of assay, preservative content, and impurity profiling of Enalapril Maleate in oral pharmaceutical formulations. Chromatographic separation was achieved using a Phenomenex Kinetex C18 column (150 × 4.6 mm, 2.6 μm) at 50 °C, with an autosampler temperature of 10 °C. A simple gradient system was employed at a flow rate of 1.0 mL min⁻¹, using phosphate buffer (pH 2.2) as mobile phase A and acetonitrile as mobile phase B, with the same buffer as diluent. A 50 µL injection volume was used, and detection was performed at 215 nm with a PDA detector. The method was validated in accordance with ICH Q2(R2) Guidelines. Specificity confirmed no interference from placebo or degradation products. The method demonstrated good linearity. The method showed excellent linearity for Enalapril 0.1–1.5 µg/mL .Observed linearity range: Impurity-C (0.1–1.5 µg/mL) and Impurity-I, Impurity-D, Impurity-F, Impurity G and Impurity H is (0.1–1.6 µg/mL)Accuracy studies for ENP, methyl paraben and propyl paraben showed mean recoveries of 99.8–100.7%, 99.3–101.1% and 99.3–100.1%, respectively, with %RSD values of 0.12–0.22%, 0.05–0.54% and 0.35–0.63%, respectively. For the investigated impurities, mean recoveries ranged from 84.6 to 107.1% at LOQ, 100% and 150% levels, with precision within the predefined acceptance criteria across relevant concentration ranges for assay, preservative, and impurities. Precision and intermediate precision showed % RSD values within acceptable limits. Accuracy was verified through recovery studies, while robustness was established by deliberate variations in flow rate, pH, and temperature. Sensitivity was confirmed through determination of LOD and LOQ, ensuring suitability for trace-level impurity analysis. The method was successfully applied to commercial formulations of Enalapril Maleate. Additionally, its environmental impact was evaluated using Analytical Eco-Scale (AES)-73, AGREE-0.61, GAPI − 72 and NEMI tools. Overall, this RP-HPLC method is reliable, reproducible and suitable for routine quality control and regulatory compliance. Enalapril maleate, HPLC, Green metric tools, Assay, Preservative, Impurities determination. Developed and validate simple and robust RP-HPLC method for simultaneous determination of assay, preservative content, and impurity profiling of Enalapril Maleate in oral dosage forms. Sensitivity of method confirmed suitability for trace-level detection of impurities through appropriate LOD and LOQ values. Advanced analytical techniques like RP-HPLC is used for Simultaneous quantification of active and preservative, impurity profiling, Preservative Impurities and analytical methods validated per ICH guidelines. Key findings of the said developed analytical methods are Eco-friendly and commercially viable to pharmaceutical analysis with high precision and accuracy. The review stresses the importance of method validation parameters (specificity, accuracy, precision, robustness) studies to ensure drug reliability. Green chemistry tools (AES, AGREE, NEMI, MoGAPI) are highlighted to promote eco-friendly pharmaceutical analysis supporting sustainable therapeutic interventions.