Enhanced Ultra High Performance Liquid Chromatographic Method for Simultaneous Determination of Organic Related impurities and Assay of Hydralazine Hydrochloride with Greenness assessment

Hydralazine Hydrochloride (HDH) is an antihypertensive drug that functions as a direct vasodilator. The present study redeveloped and validated a simple, rapid, and cost- effective chromatographic analytical method for pharmaceutical applications, enabling the simultaneous estimation of organic-related impurities and the assay. This approach improves upon existing Pharmacopoeial and literature methods by reducing analysis time, improving selectivity for additional potential impurities, and employing a Liquid Chromatography-Mass Spectrometry (LC-MS) compatible mobile phase to extend column lifespan and facilitate extended process monitoring. The adoption of Ultra High Performance Liquid Chromatography (UHPLC) was necessary to achieve these objectives. The optimized UHPLC method utilized a Shim-pack Scepter C18-120 hybrid particle trifunctional bonded column, achieving a 15-minute analysis time under gradient elution with 230nm UV detection. The 120Å pore size contributed to improved elution order. A single set of chromatographic conditions enabled the simultaneous estimation of eight specified and unspecified impurities, as well as to determination of assay, thereby enhancing process control. The method achieved detection and quantitation limits of 0.01% and 0.03%, respectively, with a linear regression coefficient (R 2 ) greater than 0.99 for each analyte. Recovery of each impurity ranged from 80% to 120% with results within 5% relative standard deviation (RSD<5%). Assay estimation demonstrated a similarity factor (Sf) between 0.98 and 1.02 and % RSD for standards below 0.73%. Repeatability and robustness were confirmed by consistent system suitability compliance, ensuring result reliability (P-value >0.05). Stress studies confirmed selectivity for degradation impurities, with a peak purity index of 0.999. The method enables impurity identification by LC-MS and supports evaluation of the intermediate purity. The greenness assessment score indicates environmental friendliness and demonstrates the cost reductions of up to 95% for solvents and 83% for analysis time.