A Quality by Design and green LC technique for the determination of mast cell stabilizer and histamine receptor antagonist (Olopatadine HCl) in multiple formulations

Mast cell stabilizer and histamine receptor antagonist olopatadine hydrochloride (OPT) assay method predicated on LC have been established for the analysis in multiple formulations. The current method dealt with ophthalmic solution, nasal spray, and tablet formulation products. The isocratic chromatography method was optimized and validated with a Boston green C8 column (150 × 4.6 mm, 5 μm i.d.). Sodium dihydrogen phosphate buffer (pH 3.5) with acetonitrile in the ratio of 75:25 (v/v) was used as a mobile phase at a flow rate of 1.0 mL min^?1 and at the column temperature of 30°C, and the detection was done at 299 nm. The method was validated as per International Council for Harmonisation (ICH) guidelines and United States Pharmacopoeia (USP). The accuracy results ranged from 99.9 to 100.7%, % relative standard deviation (RSD) from the precision was 0.5, and correlation coefficient from the linearity experiment was > 0.999. Solution stability was established for 24 h at room temperature and refrigerator conditions, and it was found that the solutions were stable. Using quality by design-based experiment designs, critical quality attributes were studied and it was found that the method was robust. In all the forced degradation studies peak purity was passed, and no interference was found at the retention time of the active component. The method validation data demonstrated that the developed method is linear, precise, accurate, specific, robust, and stable for the determination of OPT from multiple formulations. Analytical eco-scale tool, Green Analytical Procedure Index (GAPI) tool, and the National Environmental Method Index (NEMI) were used to evaluate the greenness of the method, and the analytical eco-score of 77 for the presented method was found to be excellent.