Simultaneous Determination of Three Residual Monomers in Polyvinyl Alcohol Eye Drops Using a Dual-Wavelength RP-HPLC Method and Evaluation of Its Greenness.

Polyvinyl alcohol eye drops contain high-molecular-weight polymeric raw materials and excipients whose synthesis, storage, and pharmaceutical manufacturing processes may introduce or generate residual monomers, thereby affecting the quality, safety, and stability of the formulation. Therefore, establishing a reliable analytical method for the simultaneous determination of multiple residual monomers is essential for improving the quality control of such ophthalmic formulations. In this study, a dual-wavelength reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous quantitative determination of 2-pyrrolidone, N-vinyl-2-pyrrolidone (NVP), and vinyl acetate (VA) in polyvinyl alcohol eye drops. Chromatographic separation was achieved on a NanoChrom 300 C18 column using an isocratic mobile phase consisting of water, methanol, and acetonitrile (90:5:5, v/v/v), with detection at 205 and 235 nm. The greenness and environmental sustainability of the proposed method were comprehensively evaluated using three complementary assessment tools: the Analytical Eco-Scale, the Analytical Method Greenness Score (AMGS), and the Modified Green Analytical Procedure Index (MoGAPI). The results demonstrated that the method is simple and provides satisfactory sensitivity, accuracy, and precision, making it suitable for the determination and quality control of the target residual compounds in ophthalmic formulations containing povidone as an excipient.