Clean-in-place (CIP) is a method of cleaning the interior surfaces of pipes, vessels, process equipment, filters and associated fittings, without disassembly.
CIP is commonly used for cleaning bioreactors, fermenters, mix vessels, and other equipment used in biotech manufacturing, pharmaceutical manufacturing and food and beverage manufacturing. CIP is performed to remove or obliterate previous Cell Culture batch components. It is used to remove in-process residues, control bioburden, and reduce endotoxin levels within processing equipment and systems. Residue removal is accomplished during CIP with a combination of heat, chemical action, and turbulent flow.
The Code of Federal Regulations states “Equipment and utensils shall be cleaned, maintained, and sanitized at appropriate intervals to prevent malfunctions or contamination that would alter the safety, identity, strength, quality or purity of the drug product beyond the official or other established requirements.”
Repeatable, reliable, and effective cleaning is of the utmost importance in a manufacturing facility. Cleaning procedures are validated to demonstrate that they are effective, reproducible, and under control. In order to adequately clean processing equipment, the equipment must be designed with smooth stainless steel surfaces and interconnecting piping that has cleanable joints. The chemical properties of the cleaning agents must properly interact with the chemical and physical properties of the residues being removed. A typical CIP cycle consists of many steps which often include (in order):
- Pre-rinse with WFI (water for injection) or PW (purified water) which is performed to wet the interior surface of the tank and remove residue. It also provides a non-chemical pressure test of the CIP flow path.
- Caustic solution single pass flush through the vessel to drain. Caustic is the main cleaning solution.
- Caustic solution re-circulation through the vessel.
- Intermediate WFI or PW rinse
- Acid solution wash – used to remove mineral precipitates and protein residues.
- Final rinse with WFI or PW – rinses to flush out residual cleaning agents.
- Final air blow – used to remove moisture remaining after CIP cycle.
Critical parameters must be met and remain within the specification for the duration of the cycle. If the specification is not reached or maintained, cleaning will not be ensured and will have to be repeated. Critical parameters include temperature, flow rate/supply pressure, chemical concentration, chemical contact time, and final rinse conductivity (which shows that all cleaning chemicals have been removed).