Guidance on Process validation is published by the USFDA which was awaited for quite a long time i.e from May 1987 and the draft from November 2008.The newly published guidance revises and replaces the 1987 guidance with the title "Guideline on General Principles of Process Validation"
It covers the process validation for the manufacture of human and animal drug and biological products, including active pharmaceutical ingredients (APIs or drug substances).
This guidance aligns process validation activities with a product lifecycle concept and with existing FDA guidance, including the FDA/International Conference on Harmonisation (ICH) guidances for industry, Q8(R2) Pharmaceutical Development, Q9 Quality Risk Management, and Q10 Pharmaceutical Quality System.
This guidance describes process validation activities in three stages.
Stage 1 – Process Design: The commercial manufacturing process is defined during this stage based on knowledge gained through development and scale-up activities.
The goal of this stage is to design a process suitable for routine commercial manufacturing that can consistently deliver a product that meets its quality attributes.
Stage 2 – Process Qualification: During this stage, the process design is evaluated to determine if the process is capable of reproducible commercial manufacturing.
This stage has two elements: (1) design of the facility and qualification of the equipment and utilities and (2) process performance qualification (PPQ). During Stage 2, CGMP-compliant procedures must be followed. Successful completion of Stage 2 is necessary before commercial distribution.15 Products manufactured during this stage, if acceptable, can be released for distribution.
Stage 3 – Continued Process Verification: Ongoing assurance is gained during routine production that the process remains in a state of control.
The goal of the third validation stage is continual assurance that the process remains in a state of control (the validated state) during commercial manufacture. A system or systems for detecting unplanned departures from the process as designed is essential to accomplish this goal. Adherence to the CGMP requirements, specifically, the collection and evaluation of information and data about the performance of the process, will allow detection of undesired process variability.
During this stage, a company should establish an ongoing program to collect and analyze product and process data that relate to product quality. Trained personnel should statistically trend and review the data, and the information collected should verify that the quality attributes are appropriately controlled throughout the process, according to the guidance.
You can find the Guidance at : http://www.fda.gov/downloads/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/UCM070336.pdf