A novel Six Sigma approach and eco-friendly RP-HPLC technique for determination of pimavanserin and its degraded products: Application of Box–Behnken design

A green analytical chemistry study attempts to generate environmentally friendly alternatives to dangerous compounds while reducing waste output. The study thoroughly analyzed eight green tools to determine their greenness. Given its importance in treating hallucinations and delusions produced by Parkinson’s disease psychosis, it is critical to have a reliable and precise method for identifying pimavanserin (PVS) in both pure form and pharmaceutical formulations. The current study used a straightforward approach to forced degradation experiments to establish a novel reversed-phase high-performance liquid chromatography method for evaluating stability. The method was executed on the Agilent Zorbax Eclipse Plus C18 column (100 × 4.6 mm, 3.5 μm particle size) with ultraviolet detection at 226 nm. The Box–Behnken design is the ultimate solution for identifying optimal chromatographic conditions in a timely and efficient manner, with minimal trials required. The study investigated the impact of three factors: acetonitrile ratio, column oven temperature, and flow rate on various responses, namely, retention time, tailing factor, and theoretical plates. Desirability and overlay plots were utilized to forecast the best mobile phase containing a buffer solution: acetonitrile: tetrahydrofuran in a ratio of (65: 20: 15, v/v/v), which proved highly effective in the experiments. Linearity was conducted for PVS in the 3–50 µg·mL−1 range with an R 2 coefficient of determination of 0.9997. PVS had detection and quantification limits of 1.1 and 3.5 µg·mL−1, respectively, indicating a highly significant correlation between the variables studied. PVS’s recovery percentage was determined to be 101.30%. We also used the Six Sigma lean technique to ensure precision and productivity. PVS was tested for acid, base, oxidative hydrolysis, photodegradation, and heat, as per International Council for Harmonisation guidelines. The highest degradation was obtained from oxidative hydrolysis and thermal degradation.