Introduction
This procedure provides guidance for validating sterilization and depyrogenation of equipment, and containers and closures with direct or potential contact with sterile medical devices, sterile drug products, or sterile active pharmaceutical ingredients (API).
Preventive Maintenance (PM) Measures should include, and not be limited to, the following:
For Steam
- Calibrate instruments and elements (I/Es);
- Check operation of vacuum pumps;
- Clean chamber, steam traps and drains;
- Perform leak test of the chamber;
- Replace and integrity test vent filter;
- Verify the operation of safety devices; and
- Check door seals and gaskets for deterioration.
For Dry Heat Ovens and Tunnels
- Calibrate I/Es;
- Check operation of electric heating elements;
- Operation of pressure differential monitoring equipment and alarms;* Clean chamber, belts, baffles, and dampers;
- Verify fan and belt speed;
- Replace belt when required;
- Integrity test HEPA Filters; and
- Check door seals for deterioration.
For EtO
- Calibrate I/Es;
- Check operation of vacuum pumps; • Replace vent filter;
- Verify integrity of heat exchangers;
- Clean chamber;
- Perform leak test of the chamber;
- Check operation of exhaust gas scrubbers; and
- Check door seals and gaskets for deterioration.
Critical Process Parameters (e.g., temperature, exposure time) for each type of sterilization or depyrogenation method should be automatically recorded during each phase of the sterilization/depyrogenation cycle (e.g., continuous chart recorder or print out at least once a minute).
Sterilizer Monitoring and Control I/Es should be calibrated before the operational qualification (OQ) study and routinely according to a defined calibration schedule External Monitoring and Recording I/Es (e.g., data logger and thermocouples) should be calibrated before and after the OQ study, and before and after the performance qualification (PQ) study.
One Thermocouple should be placed adjacent to the temperature controlling I/E in static, batch type sterilizers. Load patterns and/or equipment diagrams with indication of thermocouple placement should be documented as a part of qualification studies.
For continuous belt depyrogenation tunnels, thermocouples should be fed into the tunnel (i.e., trailing thermocouples) in containers distributed across the belt, at least in the first and last rows of each load.
Load Pattern and/or Equipment Diagrams with indication of biological indicators (BI) and/or endotoxin indicators (EI) placement should be documented as a part of the qualification studies.
Certificate of Analysis (COA) for Commercially Prepared BIs should contain the following information:
- Organism identification;
- Source (supplier);
- D-value and z-value;
- Survival time and kill time;
- Spore population per carrier (or mL);
- Expiration Date; and
- Storage conditions.
Custom Prepared BIs for moist heat sterilization or dry heat sterilization should be tested prior to use for survival time and kill time under the conditions in which they will be used. D-values and kill time required for complete inactivation of prepared BIs should be determined experimentally. BIs having high D-values and/or large spore populations can result in some survivors when using the overkill sterilization cycle.
The following equation illustrates the effect D-values and population size may have on kill time for a given steam sterilization cycle. Kill Time (min at 121) = D121 x(Log10 N0 +4) D(121C) = time in minutes required to reduce the microbial population by ninety (90) percent or one log cycle at a reference temperature of 121oC.
N0 =Initial BI sporepopulation.
D-value studies should be performed using the Biological Indicators-Resistance Performance Test (e.g., as indicated in the USP).
I Lots Demonstrating Kill Times in excess of what is required to demonstrate the sterilization end-point for the process being evaluated should not be used.
All BIs Used in Validation Studies should be accounted for, before and after processing.
For Steam Sterilization Processes, BIs are available in four (4) forms:
Spores added to a carrier (e.g., a disk or strip of filter paper, glass, plastic or other material) and packaged to maintain the integrity and viability of the inoculated carrier (preferred and most commonly used in non-product sterilization validation);
- Self-contained packaged indicator that includes the culture medium separated from the BI (e.g., a paper strip surrounding a sealed ampoule containing culture medium that is activated after exposure);
- Self-contained packaged indicator that includes the spores suspended in the culture medium in a sealed ampoule (most often used for submersion in liquids); and
- Spore suspension added to representative units of the product, simulated product, or onto non-product surfaces (e.g., closures). Such suspensions are most often used for product terminal sterilization validation.
Steam Sterilization Cycle Development should include the following:
- Runs performed using BIs (e.g., Geobacillus stearothermophilus, formerly referred to as Bacillus stearothermophilus) which have a predetermined spore population (e.g., 105 to 106), D-value, and kill time; and
- Incubation of BIs at 55oC-60oC with no growth after seven(7) days or at the temperature and time periods recommended by the BI supplier.
Steam Sterilization OQ/PQ Studies should be performed and include, and not be limited to, the following:
- A minimum of three (3) temperature distribution runs on an empty chamber to confirm heating uniformity and identify the slowest-to-heat zone;
- Heat penetration runs on each different load configuration to identify cold spots, the effect of loading on thermal input, and the worst case load configuration;
- A minimum of three (3) consecutive, successful runs on the worst case load configuration using minimum cycle parameters and BIs and meeting all validation acceptance criteria; and
- One run with the minimum load configuration.
For DH Sterilization Processes, BIs are available in two forms:
- Spores added to a carrier (e.g., paper strips); and
- Spores added to representative units (e.g., inoculated stainless steel coupons).
Where the process has been shown to depyrogenate by inactivation of three (3) logs of endotoxin, it is not necessary to challenge with bacterial spores.
DH Sterilization Cycle Development should include the following:
- Runs conducted using BIs (i.e., Bacillus atropheus formerly referred to as Bacillus subtilis var. niger) which have a predetermined spore population (e.g., 105 to 106), D-value, and kill time;
- Calculation of FH in the coolest location in the load to determine the degree of lethality as a function of process parameters; and
- Incubation of BIs at 30oC-35oC withno growthafter seven(7) days or at the temperature and time interval recommended by the BI supplier.
DH Sterilization (e.g., 140oC -180oC) OQ/PQ Studies should be performed and include, and not be limited to, the following:
- A minimum of three (3) temperature distribution runs on an empty chamber to confirm heating uniformity and identify the slowest-to-heat zone;
- Heat penetration runs on each different load configuration, including minimum and maximum loads, to identify cold spots and the worst case load configuration; and
- A minimum of three (3) consecutive, successful runs using the worst case load configuration using minimum cycle parameters and BIs and meeting all validation acceptance criteria.
DH Depyrogenation (e.g., > 180oC) OQ/PQ Studies for DH ovens should be performed and include, and not be limited to, the following:
A minimum of three (3) temperature distribution runs on an empty chamber to confirm heating uniformity and identify the slowest-to-heat zone;
- Heat penetration runs on different load configuration using a matrixing approach (e.g., smallest and largest glass vials) including minimum and maximum loads, to identify cold spots and the worst case load configuration; and
- A minimum of three (3) consecutive, successful runs using the worst case load configuration using minimum cycle parameters and EIs and meeting all validation acceptance criteria.
DH Depyrogenation OQ/PQ Studies for continuous belt tunnels should consist of a minimum of three (3) consecutive, successful runs based on a matrix approach for varying vial sizes, using minimum cycle parameters, and EIs and meeting all validation acceptance criteria, to confirm heating uniformity in each tunnel zone and across the belt, and to identify tunnel cold spots.
DH Tunnel Temperature Distribution Runs should evaluate and determine the following:
- Effects that tunnel load (e.g., empty, partially full, and full) has on temperature distribution;
- Positioning of baffle plates or gates in each tunnel zone for each container size; and
- Belt speed for each container size.
Each Lot of EtO Gas supplied by a vendor should be approved by the Site Quality Team and have a COA that certifies the gas concentration.
For EtO Sterilization Processes, BIs are available in two (2) forms:
- Spores added to a carrier (e.g., paper strips); and
- Self-contained packaged indicator that includes the culture medium separated from the BI (e.g., Attest, test pack).
EtO Sterilization Cycle Development should use the Half-Cycle Approach and include the following:
- Conduct runs using BIs (i.e., Bacillus atropheus, formerly referred to as Bacillus subtilis var. niger), which have a predetermined spore population (e.g., 105 to 106) and known D-value, and kill time;
- Determine the sterilization cycle time required to inactivate the BIs and then double the EtO exposure time;
- Incubate BIs at 30oC-35oC with no growth after seven(7) days; or at the temperature and time interval recommended by the BI supplier
The EtO Sterilization Cycle should include:
- Preconditioning to achieve specified temperature and RH parameters;
- Sterilization with EtO gas or EtO gas mixture; and
- Removal of EtO gas after sterilization.
EtO Sterilization OQ/PQ Studies should be performed and include, and not be limited to, the following:
- A minimum of three (3) temperature distribution runs on an empty chamber to confirm heating uniformity and verify RH;
- Gas penetration runs using multi-parameter process indicators on each different load configuration to determine the worst case load configuration; and
- A minimum of three (3) consecutive, successful runs on the worst case load configuration using minimum cycle parameters (i.e., temperature, RH, and EtO gas concentration) and BIs and meeting all validation acceptance criteria.