Validation is defined as the establishing of documented evidence which provides a high degree of assurance that a planned process will consistently perform according to the intended specified outcomes. Validation studies are performed for analytical tests, equipment, facility systems such as air, water, steam, and for processes such as the manufacturing processes, cleaning, sterilization, sterile filling, lyophilization, etc. There will be a separate validation for the lyophilizer as an equipment item and for the lyophilization process; for the cleaning of glassware and the cleaning of the facility; and for the sterilization process and for the sterility test. Every step of the process of manufacture of a drug product must be shown to perform as intended. Validation studies verify the system under test under the extremes expected during the process to prove that the system remains in control. Once the system or process has been validated, it is expected that it remains in control, provided no changes are made. In the event that modifications are made, or problems occur, or equipment is replaced or relocated, revalidation is performed.