CSIC stability studies

Standard buffer solutions with pH values of 1.2, 4, 5, 7, 9, and 10 were prepared according to the United States Pharmacopeia (USP) [26]. CSIC was first dissolved in acetonitrile and then mixed with each buffer solution individually to achieve a final nominal concentration of 100 μg/mL. Sample solutions were sonicated in a water bath until the drug particles completely disappeared based on visual observation. Samples were then covered with aluminum foil and stored at room temperature. Aliquots were taken daily for 10 days, and the drug content was analyzed by HPLC as described above. All studies were conducted in triplicate.