VAL-175 Validation of Autoclaves, Autoclave Loads and Cycles

PURPOSE

This standard operating procedure outlines the validation approach for autoclaves, autoclave loads and autoclave cycles a GMP site.

SCOPE

This document describes the validation and re-validation approach to sterilisation activities conducted utilising autoclaves a GMP site.

RESPONSIBILITIES

The department responsibilities in regards to validation of the autoclave, cycle and loads are outlined below.

i. Validation

– Prepare, approve and execute protocols in accordance with this SOP.

– Develop validation program and re-validation plans.

– Review and approve validation test results.

– Ensure only fully validated load configurations and cycle parameters are documented in the relevant operational SOPs.

ii. Quality Assurance

– Ensure compliance with this SOP with specific regard to Installation, Operational and Performance Qualification and Re-validation activities.

– Ensure compliance with current corporate policy and regulatory requirements.

– Ensure operational compliance to local Department of Agriculture requirements.

iii. Quality Control

– Review and approve validation protocols and test documentation.

– Provide access to equipment and resources to allow for validation work to be carried out.

– To ensure SOPs contain only current and accurate load patterns and associated autoclave cycles

– To generate change controls for autoclave cycle/load additions/changes

– Perform Biological Indicator (BI) analysis.

iv. Engineering

– Review and approve validation protocols and test documentation.

– Ensure compliance with this SOP with specific regards to Maintenance, Calibration and Change Controls.

– Ensure that autoclave equipment utilities and sensors are compliant with operating limits

– Ensure autoclave cycle programs, PLCs and chart recorders are up to date, correct and operational

v. Production / Development

– Review and approve validation protocols and test documentation

– Provide access to equipment and resources to allow for validation work to be carried out

– To ensure SOPs contain only current and accurate load patterns and associated autoclave cycles

– To generate change controls for autoclave cycle/load additions/changes

DEFINITIONS

– BI – a biological indicator is a spore strip/ ampoule or inoculated item with a population of spores of no less than 10⁶ Geobacillus stearothermophilus with known D and Z values.

– Control BI – A BI of the same lot as those used for testing, but one that was not exposed to the sterilisation cycle.

– Chamber – The part of the steriliser that the load is placed in.

– Load – A specified combination of the type and number of items and  their distribution within the autoclave chamber.

– Autoclave Cycle: An operating program which defines the phases, critical parameters and conditions utilised for conducting sterilisation of a given load configuration.

– Autoclave Phase: A stage in operation of an autoclave cycle. e.g. holding of the chamber at a vacuum state for 2 minutes.

– Conditional Approval – Approval to resume production use of an autoclave prior to the final re-qualification report approval based on specified requirements and conditions.

– Equilibration Time – The period that elapses between the attainment of the sterilisation temperature of 121°C in the sterile chamber and the attainment of the sterilisation temperature at all test points within the load.

– Exposure Time – An equipment based parameter that is the time at which the autoclave is held at the desired operating temperature.

– D-value – The D value is defined as the time in minutes at a given set of parameters required to reduce the population of a biological indicator (BI) by one log.

– F₀ Value – Calculated sterilisation time (equivalency value) at the observed temperature and time equivalent to the sterilisation time at the base temperature at 121°C. The calculation is as follows:

F₀ = ∆t∑10^(T-121)/z

Where T is the actual temperature in ^oC at time (t)

∆t is the measurement interval (minutes)

– Z value is defined as the number of degrees of temperature change required for a one log or a 90% change in the D-value (°C)

– Heat Penetration (study): Refers to the measurement of the temperature of the load during evaluation of an autoclave cycle (for the given load)

– Heat Distribution (study): Refers to the measurement of the temperature of the autoclave chamber during operation of a load containing autoclave cycle evaluation.

– Holding Time -Period for which the temperature at all points within the steriliser is held within the sterilisation temperature band.

– Liquid Load – The sterilisation of liquids in containers.

– Porous Load – A load which requires the air to be removed from the equipment or product for effective sterilisation to occur.

– Stabilisation Period – Initial Period up to and after the attainment of the chamber temperature set point that a controller may require before achieving steady state temperature control and uniformity.

– Sterilisation Band – This is defined as the acceptable sterilisation temperature fluctuation range.

– Department of Agriculture – Regulatory body responsible for management of quarantine regulations.

 SAFETY AND PROCESS SPECIFIC INFORMATION

i. Safety

– All safety requirements for relevant autoclave containing areas at any GMP must be followed at all times.

– Safety glasses as per biological production gowning requirements for class B/D areas and gloves when handling equipment at a high temperature (≥ 40°C).

– When autoclaving glass carboys, ensure a cage is installed around the carboy prior to autoclaving

– Always keep biological indicators in shatter proof containers. When handling biological indicators, ensure gloves are worn prior to handling. Dispose of unused biological indicators in the QC laboratory clinical waste.

– Allow equipment to cool prior to removing/placing biological indicators. Beware of condensate which may cause the BI surfaces to become slippery when reacting with aluminium tape adhesive.

ii. Process

– Obtain a work permit to conduct activities on Autoclaves for validation.

– Attach an equipment “tag-out” sign near the autoclave or autoclave controls. Refer to Form-760 “Equipment Tag Out for Validation”. This is to indicate the autoclave equipment is under validation control and isolated from production use.

F₀ CALCULATION THEORY AND DATA ANALYSIS

– F₀ values must be calculated for every thermocouple located in the chamber and within loads.

– The following equation must be used and entered correctly in an excel spread sheet for calculation of the F₀ derived at the measurement location. The formula below must be entered into each cell where the corresponding recorded temperature is equal or above 100°C:

F₀=∆t x 10^(T-121)/z

Where ∆t = 0.0167 minutes (1sec/60sec = 0.0167 minutes) equivalent to a 1 second data   sampling interval.

             z = 10^oC

            T = Temperature (^oC) value for that particular time point

Thus F₀= 0.0167 x 10^(T-121)/10 for each sample data point.

The accumulated F₀ is then calculated on the spreadsheet (refer to table below)

– The formula to be typed into an excel spreadsheet for each individual cell is

 =0.0167*10^((Cell Value -121)/10):

– The F₀ values calculated for each cell are added together over the duration of the SIP time period to give the total F₀ value for that particular location.

 Example (Assumption of 1 second sampling interval):

The equation entered must be verified to be correct by a second validation engineer or delegate. The verification signature must be on the results sheet of each run in the validation report.

PROCEDURE – VALIDATION OF AN AUTOCLAVE AND/OR AUTOCLAVE INSTALLATION

i. Prerequisites

– A user requirement specification (URS) document containing the equipment requirements shall be referenced if available.

– An Equipment Verification (EV) shall be executed prior to Performance Qualification (PQ). Any deviations or failures to meet acceptance criteria shall be resolved.

– All critical instruments shall be calibrated and maintained in accordance with site procedures.

ii. Equipment Verification (EV) Protocol

The EV protocol should include the following:

– Utility connection and supply checks;

– Instrumentation verification (as per BS EN 285 sections 6.1 and 6.2);

– Alarms, Interlocks, Controls and Indicators are functioning as specified by the manufacturer, as directed in the URS and/or required by the owner.

– An empty chamber temperature distribution study

iii. Acceptance Criteria

– The chamber is capable of maintaining a temperature within ±1°C (Celsius) of the mean chamber temperature at each time point.

– All temperatures are within the sterilisation band.

– All cycle parameters match the programmed parameters

– Prior to use, the thermocouples meet the required calibration tolerance of at least ±0.1°C. (BS EN285) Averaged over the number of thermocouple channels.

– Post Use calibration verification check – 80% thermocouples within ±0.8°C of the heat source.

– Recorded temperatures measured by the control system must be within ±2°C of the temperature recorded by the thermocouple(s) at the same tested location.

– Recorded pressure indication measured by the control system must be within ± 2kPa (or 0.5% if range different to 0 – 400kPa) of the pressure recorded by the external pressure transmitter.

– If any of the above tests fail to meet the acceptance criteria, complete a deviation report. Upon resolving the cause of the failure the test can be repeated if the nature of the failure does not warrant the closure of the study and the re-issuing or amendment of the protocol.

PROCEDURE – AUTOCLAVE AND LOAD CYCLE VALIDATION – PREPARATION

i. Documentation

– Obtain a copy of Form-765 “Documentation Verification and Cycle Review” and conduct a review.

– Conduct a review as per Form-770 “Validation Cycle Review”

– Complete Form-775 “Change control, deviation, preventative and corrective maintenance summary sheet”

– Obtain Form-780 “Autoclave Validation Protocol” and conduct the cycle/load review, if there are no changes to the existing functional requirements of the autoclave. A validation protocol is required to be generated if there are any new cycle types to be qualified or any new/changed load configurations (to be run using pre-existing cycles).

– Conduct activities listed on Form-785 “Autoclave Validation Documents Checklist” if a protocol is not required to be raised for validation purposes.

– Complete a summary report or equivalent autoclave report form (or load cycle acceptance form) on completion of validation activities.

ii. Cycle and Load Performance Review

If there are new cycles and/or load types required to be validated as per section 1.4, then a protocol must be generated and circulated for approval. The protocol must be reviewed and approved prior to executing protocol activities.

Review the autoclave validation spreadsheet for the respective autoclave to determine which cycles to target for re-validation purposes. The process of selecting validation cycles for the purpose of revalidation will be determined based on the following criteria and should be conducted to ensure the selected cycles incorporate worst case challenges.

 – Previous Validation Trials – Review the autoclave validation spreadsheet and determine the cycle and load type that should be evaluated based on their associated risk, criticality, complexity or frequency of revalidation.

 – Performance History – A review of Change Control, Deviation, and Preventative and Corrective Maintenance activities for the previous 12 months will be conducted.

 – Load Configuration – Where there is more than one load configuration for a given cycle the load containing the worst case components will be selected.

 – Cycle Configuration – Cycles selected for revalidation should incorporate where relevant at least one of each cycle style eg. Porous, F₀ regulated, time and temperature based etc.

iii. Cycle Development and Assessment

 Sterilisation cycles have been developed following two main approaches to development of sterilisation cycles:

– Load Configuration Approach: where the placement of each item in a load is pre-determined. The most difficult to heat item within a defined load configuration is identified and used as the test item/location.  Only items defined in those loads are used.

– Bracketing approach: where load patterns are designed based on a predefined maximum and minimum load. Loads are designed based on their common elements and perceived heating kinetics. Where this approach is adopted a clear rationale of the range within the pattern must be clearly documented.

If the cycle or load to be qualified is a new cycle/load three validation runs at a minimum should be considered. The following documentation should be created or updated.

– Autoclave Cycle parameter and configuration sheet

– Operating instruction or procedure including loading diagrams.

– Cycle rationale description

iv. Instrumentation Calibration Requirements and Data-Logger Preparation

Ensure that all instrumentation calibration records are current. Obtain copies of instrumentation calibration records. Thermocouples are calibrated against a reputed traceable temperature source.

For thermocouple verification records, ensure that the pre and post calibration verification activities meet the following criteria.

– Prior to use, the thermocouples meet the required calibration tolerance of at least ±0.1°C. (BS EN285) Averaged over the number of thermocouple channels.

– Post Use calibration verification check – 80% thermocouples within ±0.8°C of the heat source.

Synchronise the clock time on the data logger to within ±1 minute of the Autoclave PLC/SCADA clock.

Set the data logging unit to archive the data onto external media (USB or flash card) at least every hour.

Always keep one USB drive or flash card inserted into the data logger, so that data maybe routinely archived.

v. Number of Thermocouples

– At least seven (7) thermocouples must be utilised for chamber monitoring during cycle evaluation. This is inclusive of the drain and temperature sensor locations. (BS EN 285 23.5.2)

– It is recommended to have at least a further seven (7) thermocouples prepared for temperature evaluation of the load and in the event other thermocouple(s) are damaged or destroyed.

– Calibrate the thermocouples (as installed) on the data logger against a certified temperature source. Conduct the temperature verifications as per the SOP for the respective data logger.

– Where consecutive autoclave / SIP evaluations are being conducted, pre and post trial thermocouple calibration verifications may be conducted after bracketing the series of runs.

– The data sampling rate for each channel should be 1 sec (or less). (BS EN 285 23.5.2)

– T – Type thermocouples are to be used by default. Other thermocouple types may be utilised if referenced specifically in the protocol or execution sheets.

vi. Pressure Transmitters

– The pressure transmitter should be capable of recording a range between 0 – 400kPa Absolute (-100kPa – 300kPa Gauge).

– The pressure transmitter should be installed on the access port to measure the chamber pressure of the autoclave (not to be confused with autoclave jacket port)

AUTOCLAVE LOAD AND CYCLE VALIDATION – ACCEPTANCE CRITERIA

This section proscribes the acceptance criteria for both chamber and load evaluation during performance qualification of an autoclave cycle for each respective load.

i. Dry Cycle Acceptance Criteria (Dry Porous Loads – without liquid content)

– The chamber thermocouples are capable of maintaining a temperature within ±1°C (Celsius) of the mean chamber temperature at each time point. Instantaneous variations are permitted provided they do not exceed more than 5 seconds.

– All temperatures are within the sterilisation band (-1°C and + 2 °C of the set point).

– All cycle parameters on the report match the programmed parameters shown on the parameters list.

– Prior to use, the thermocouples meet the required calibration tolerance of at least ±0.5°C. (BS EN285) Averaged over the number of thermocouple channels.

– Post Use calibration verification check – 80% thermocouples within ±0.8°C of the heat source.

– Recorded temperatures measured by the control system must be within ±2°C of the temperature recorded by the thermocouple(s) at the same tested location.

– Recorded pressure indication measured by the control system must be within ± 2kPa (or 0.5% if range different to 0 – 400kPa) of the pressure recorded by the external pressure transmitter

– Calculated F₀ values for each location within the load must be greater than 22 minutes

– Some regulatory agency requires waste cycles must have calculated F₀ value equal to or greater than 30 minutes.

– The measured value for the chamber temperature is within ±2°C of the corresponding saturated temperature at the pressure measured by the pressure transducer. This is assessed by taking the readings at the mid-point of the steam sterilising stage for a 1 minute time period and averaging the chamber load temperatures for the comparison.

– The Autoclave Load should be visibly dry (free of pooled liquid condensate) on cycle completion

ii. Wet Cycle Acceptance Criteria (Liquid Containing Loads)

– The chamber thermocouples are capable of maintaining a temperature within ±1°C (Celsius) of the mean chamber temperature at each time point. Instantaneous variations are permitted provided they do not exceed more than 5 seconds.

– All chamber temperatures are within the programmed parameters for Temperature regulated cycles (-1°C and + 2 °C of the set point). This does not apply to F₀ or Pressure regulated cycles.

– All cycle parameters on the report match the programmed parameters shown on the parameters list.

– Prior to use, the thermocouples meet the required calibration tolerance of at least ±0.5°C. (BS EN285) Averaged over the number of thermocouple channels.

– Post Use calibration verification check – 80% thermocouples within ±0.8°C of the heat source.

– Recorded temperatures measured by the control system must be within ±2°C of the temperature recorded by the thermocouple(s) at the same tested location.

– Recorded pressure indication measured by the control system must be within ± 2kPa (or 0.5% if range different to 0 – 400kPa) of the pressure recorded by the external pressure transmitter

– Calculated F₀ values for each location within the load should be greater than 22 minutes for a standard load and F₀ greater 30 minutes for any cycles requiring compliance to some other regulations where the load “core” temperature is not measured and F₀ ≥ 15min where the load “core” temperature is evaluated.

– Where the load is heat sensitive, an accumulated F₀ value of ≤15 minutes is permitted with appropriate justification.

– For loads with temperature sensitive cycles, the core temperature must be measured if a F₀ of 15 minutes is to be utilised.

– The measured value for the chamber temperature is within ±2°C of the corresponding saturated temperature at the pressure measured by the pressure transducer. This is assessed by taking the readings at the mid-point of the steam sterilising stage for a 1 minute time period and averaging the chamber load temperatures for the comparison.

– All liquid temperatures at the end of the cycle are below or equal to 90^o

PROCEDURE – AUTOCLAVE AND LOAD CYCLE EVALUATION – EMPTY CHAMBER PERFORMANCE CHECK

– For autoclaves with vacuum cycles install testing equipment in the autoclave and conduct a leak test using Form-805 “Vacuum Leak Test”.

– For autoclaves with vacuum cycles conduct a Bowie Dick steam penetration and air removal test using Form-790 “Steam Penetration Air Removal (Bowie Dick) Test”.

– For autoclaves with only downward displacement conduct a Pressure Regulator Test using Form-795 “Pressure Regulator Test for Autoclaves”.

– For autoclaves with only downward displacement conduct an Empty Chamber Test using Form-800 “Empty Chamber Test for Autoclaves”.

PROCEDURE – AUTOCLAVE AND LOAD CYCLE EVALUATION – EXECUTION

i. Dry Cycles (Dry Porous Loads)

– Organise with the Media Preparation department to set up the required load type.

– Place at least one thermocouple at a drain location

– Locate one thermocouple at the load temperature probe location

– Set up at least another six thermocouple channels to monitor the heat distribution in the chamber.

– Enter details in the Heat Penetration / Heat Distribution study VAL-180 “Heat Penetration Heat Distribution Study” for the respective load and cycle type.

– Place thermocouples within selected locations within the load. The locations should be representative of worst case locations where it appears that steam would be difficult to penetrate.

– Place biological indicators at locations representative of poor steam flow locations.

– Where tubing or closed ended vessels are present ensure that the internal volumes of tubing and closed ended vessels are monitored with at least one thermocouple channel.

– Start the collection of data on the data logger. Where the unit permits, enter run details into the file names.

– Ensure the chart recorder is in the operating position (where applicable)

– Start the autoclave cycle on the controlling PLC/SCADA or via manual valves depending on the autoclave type.

– On completion of the cycle, collect the report and charting data from the data recorder. Also stop the data logger from collecting data and copy / archive the file to removable media (USB/Flash Card). Copy the file into the project folder.

– Complete activities as per VAL-180 “Heat Penetration Heat Distribution Study” and submit biological indicators to QC for testing.

– On completion of the final trial, conduct calibration verification of the thermocouples using a certified temperature source.

ii. Wet Cycles (Liquid Loads)

– Organise with the Media Preparation department to set up the required load type.

– Place at least one thermocouple at a drain location.

– Locate one thermocouple at the load temperature probe location

– Set up at least another six thermocouple channels to monitor the heat distribution in the chamber.

– Enter details in the Heat Penetration / Heat Distribution study VAL-180 for the respective load and cycle type.

– Place thermocouples within selected (worst case) locations within the liquid with an accompanying “wet-type” biological indicator.

– Place thermocouples within the air containing portion of selected liquid containers of the load. An accompanying biological indicator may be placed within air containing portion where it may be considered that there may be a higher risk of lesser steam flow and air evacuation.

– Where tubing or closed ended vessels are present ensure that the internal volumes of tubing and closed ended vessels are monitored with at least one thermocouple channel.

– Start the collection of data on the data logger. Where the unit permits, enter run details into the file names.

– Ensure the chart recorder is in the operating position (where applicable)

– Start the autoclave cycle on the controlling PLC/SCADA or via manual valves depending on the autoclave type.

– On completion of the cycle, collect the report and charting data from the data recorder. Also stop the data logger from collecting data and copy / archive the file to removable media (USB/Flash Card). Copy the file into the project folder.

– Complete activities as per VAL-180 “Heat Penetration Heat Distribution Study” and submit biological indicators to QC for testing.

– On completion of the final trial, conduct calibration verification of the thermocouples using a certified temperature source.

PROCEDURE – AUTOCLAVE AND LOAD CYCLE EVALUATION – REPORTING

i. Deviation Reports

If any of the autoclave trials or tests fails to meet the acceptance criteria, complete a deviation report. Trials should not continue until an agreed course of action has been obtained. Upon resolving the cause of any failure(s) the test can be repeated if the nature of the failure does not warrant the closure of the study and the re-issuing or amendment of the protocol. Deviation reports should be completed utilising VAL-075 ‘Validation Deviation Management’ and Form-130 ‘Validation Protocol Deviation Reporting Form’.

ii. Conditional Release

– A cycle may be released for the use of production prior to final approval of the validation report where a conditional release is granted.

– Conditional Release may be granted only when thermometric and barometric data has been evaluated and considered acceptable and BI tests have passed. Conditional release may also occur only when any outstanding deviation reports have been completed and accepted.

– The Validation Department is responsible for issuing the conditional release document Form-750 “Conditional Release Form” for QA approval.

iii. Cycle Reporting

Following receipt of all test results and completion of data analysis, for review of performance of each trial evaluation, complete Form-755 ‘Autoclave Cycle Acceptance Review’

iv. Summary Reporting

– A summary validation report shall be prepared on completion of trial execution, and contain the following:

– An evaluation of the data (This may include a graph of the chamber and load temperature performance and chamber pressure).

– A copy of the data generated from the cycle evaluation.

– A comparison of the results to the procedural steps and parameters utilised.

– Documentation of the maximum and minimum temperatures, pressures and F₀ values, where appropriate, from the exposure period of each run.

– Comparison of the values between the trial cycle evaluations.

– There should be confirmation that SOP(s) used in the execution of the validation for the successful runs are finalised and approved. Conclusions based upon the execution of the study shall be incorporated into the SOP(s) applicable to the load studied.

– The ability of the steam sterilisation process to inactivate micro-organisms to the required level shall be demonstrated by the completion of the validation and by the approval of the validation report. Where product is being sterilised, the compatibility of the sterilisation process with the product shall be confirmed through stability and analytical studies.

RE-VALIDATION APPROACH

– Autoclaves used for the sterilisation of loads that will be used in production or products must be validated every 12 months (1 year).

– Autoclaves used for the sterilisation of loads that will not be used in production/products and/or decontamination of waste must be validated every 36 months (3 years).

– Before the commencement of re-validation activities a review of all validation cycles and there various load configuration shall be conducted to select the most appropriate cycles to revalidate.

PRODUCTION USE OF AUTOCLAVES DURING “TAG-OUT” FOR VALIDATION

USAGE CONDITIONS

Where the production department requires use of the autoclave, whilst validation thermocouple wiring is installed in-situ, a vacuum leak-rate test must be performed and meet the acceptance criteria prior to the production department conducting the standard cycle operation. The vacuum leak rate test report and chart should be kept with the validation documentation for traceability purposes.

REFERENCED DOCUMENTS