Remifentanil is a potent opioid analgesic used for pain management in anesthesia and intensive care. However, during its production, impurities may be present, which can affect its quality, safety, and efficacy. These impurities may include related substances, residual solvents, and degradation products. Therefore, their identification and control are crucial to ensure the purity and potency of remifentanil and to minimize the risk of adverse effects on patients.