A novel, dual gradient LC method for quantification of vardenafil (VR) and its degradant products was developed with a multivariate approach. In the QbD approach, primary parameters were screened from the Ishikawa diagram and studied via Plackett Barman’s design. Critical factors (mobile phase composition A, mobile phase composition B, temperature and flow rate) were optimized by central composite design (CCD). Optimized dual gradient method includes A: (water:ACN) (400:100, v/v) pH adjusted in the aqueous phase to 4.7 with acetic acid, B: (water: ACN) (200:300, v/v), 0.9 mL/min flow rate, 20 °C temperature and 36 min as run time. Found eight degradant peaks of VR in different stress conditions were evaluated by LC–PDA and are different from USP 2018 monograph. The study reveals that VR is prone to degrade in sunlight, thermal and hydrolysis, while stable in oxidation. The developed LC method found sensitive, specific, robust with linearity ranging 10–35 µg/mL and correlation coefficient (R²) 0.9997. The fully validated stability-indicating method is green, buffer-free, LC–MS compatible, precise, robust and accurate. The developed method can be successfully applied to monitor the stability of VR from its marketed formulation and can be extrapolated to measure the VR from biological samples.

采用多变量方法开发了一种用于定量伐地那非 (VR) 及其降解产物的新型双梯度 LC 方法。在 QbD 方法中，主要参数是从 Ishikawa 图中筛选出来的，并通过 Plackett Barman 的设计进行研究。关键因素（流动相组成 A、流动相组成 B、温度和流速）通过中心复合设计 (CCD) 进行了优化。优化的双梯度方法包括 A：（水：ACN）（400：100，v/v）用乙酸将水相中的 pH 值调节至 4.7，B：（水：ACN）（200：300，v/v）， 0.9 mL/min 流速，20 °C 温度和 36 min 作为运行时间。发现 8 个不同应力条件下 VR 降解峰由 LC-PDA 评估，与 USP 2018 专着不同。研究表明，VR 容易在阳光、热和水解作用下降解，同时在氧化中稳定。开发出的 LC 方法灵敏、特异、稳定，线性范围为 10–35 µg/mL，相关系数（R ² ) 0.9997。经充分验证的稳定性指示方法是绿色的、无缓冲液、LC-MS 兼容、精确、稳定且准确。所开发的方法可以成功地应用于监测其上市配方中 VR 的稳定性，并可以外推以测量生物样品中的 VR。