Cilnidipine is a calcium channel blocker used to treat hypertension. Impurities in cilnidipine can affect its safety and efficacy. These impurities can arise from various sources, including the manufacturing process, storage conditions, and degradation over time. It is essential to monitor and control impurities to ensure the quality and safety of cilnidipine products. Various analytical techniques are used to identify and quantify impurities in cilnidipine formulations.