We report an ideal method for quantifying impurities in mycophenolate mofetil drug substances and their oral suspension preparations. We developed a systematic and eco-friendly analytical approach utilizing quality by design (QbD) and green chemistry principles. Initially, the critical method parameters (CMPs) were screened using a D-optimal design. The robust final method conditions were optimized using a systematic central composite design (CCD). Through graphical and numerical optimization, the protocol conditions were augmented. The pH of mobile phase buffer (25 mM KH2PO4) (MP-A), initial gradient composition (% MP-A), flow rate (mL min−1), and column oven temperatures (°C) are 4.05, 87, 0.4, and 30, respectively. The best possible separation between the critical pairs was achieved while using the Waters Acquity UPLC BEH C18 (100 × 2.1) mm, 1.7 µm analytical column. A mixture of water and acetonitrile in the ratio of 30:70 (v/v) was used as mobile phase-B for the gradient elution. The analytical method was validated in agreement with ICH and USP guidelines. The specificity results revealed that no peaks interfered with the impurities and MPM. The mean recovery of the impurities ranged between 96.2 and 102.7%, and the linearity results r > 0.999 across the range of LOQ – 150%. The precision results (%RSD) ranged between 0.8 and 4.5%. The degradation products formed during the base-induced degradation were identified as isomers of mycophenolic acid and sorbitol esters using Q-ToF LC–MS and their molecular and fragment ion peaks. The developed method eco-friendliness and greenness were assessed using analytical greenness (AGREE), green analytical procedure index (GAPI), and analytical eco score, and found it is green.
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 Â 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 À1 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.
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