This SOP outlines the standardized procedure for the proper operation and preventive maintenance of HPLC systems used in pharmaceutical analysis. It includes steps for system startup, sequence programming, injection, data acquisition, shutdown, and cleaning procedures. It also covers periodic maintenance tasks such as pump seal replacement, lamp usage monitoring, and mobile phase line flushing. The aim is to ensure optimal performance, minimize downtime, and maintain the integrity and reliability of analytical data. This SOP applies to all personnel responsible for operating or maintaining HPLC systems in the quality control or analytical development laboratories.