3.4.3. Preparation of Standard Solutions

A stock standard solution of rivastigmine (1200 µg/mL) was prepared by dissolving 0.12 g of the drug in acetonitrile using a 100 mL volumetric flask. Five working solutions (24, 48, 72, 120, 840 µg/mL) were prepared by diluting an adequate amount of stock standard solution with acetonitrile in a 25 mL volumetric flask. All analyses were performed in triplicate (*n* = 3). The method was validated according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines for linearity, precision, accuracy, specificity, and robustness [5,49]. The developed method was shown to be linear, precise, selective, and robust (Supplementary Data, Sections 1 and 2), and was used in the following studies.
