Validation and Control of Porous Load Sterilisation

Transcription

1 Validation and Control of Porous Load Sterilisation Crown Plaza Hotel, Santry; October 14 th 2010 Gerard Sheridan 14th October 2010 Slide 1

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4 Overview Regulatory Guidance and Standards Terminology and Definitions Key Factors Validation Approach Thermometric Microbiological Application of F 0 concept Routine Monitoring Summary 14th October 2010 Slide 4

5 Regulatory Guidance and Standards EU GMP HTM 2010 EN 285 ISO th October 2010 Slide 5

6 Regulatory Guidance and Standards EU GMP, Annex All sterilisation processes should be validated efficacy in achieving the desired sterilising conditions in all parts of each type of load to be processed should be demonstrated by physical measurements and by biological indicators where appropriate. 85. For effective sterilisation the whole of the material must be subjected to the required treatment and the process should be designed to ensure that this is achieved. 86. Validated loading patterns should be established for all sterilisation processes. 14th October 2010 Slide 6

7 Regulatory Guidance and Standards HTM 2010 Part 3 Sterilization Validation and Verification Scope A guidance document to NHS Covers a range of sterilization processes Provides validation methodology Longstanding source of reference Has served to provide a uniform basis for approach to validation and control moist heat sterilisation Currency? 14th October 2010 Slide 7

8 Regulatory Guidance and Standards EN 285 STERILIZATION - STEAM STERILIZERS LARGE STERILIZERS Scope Does not specify requirements for the validation and routine control of sterilization by moist heat 14th October 2010 Slide 8

9 Regulatory Guidance and Standards ISO Sterilization of health care products - Moist heat - Part 1: Requirements for the development, validation and routine control of a sterilization process for medical devices Scope Medical devices NOTE: Although the scope of this part of ISO is limited to medical devices, it specifies requirements and provides guidance that may be applicable to other health care products 14th October 2010 Slide 9

10 Terminology and Definitions Complete understanding of terminology Appropriate assessment of acceptance criteria Validity of testing! Uniform understanding Misunderstandings = Deficiencies! 14th October 2010 Slide 10

11 Key Terminology Sterilization temperature Minimum acceptable temperature of the sterilization temperature band Therefore : Minimum temperature on which the evaluation of the sterilisation efficacy is based Sterilization temperature band The range of temperatures which may prevail throughout the load during the holding time. These temperatures are expressed as a minimum acceptable (the sterilization temperature) and a maximum allowable, and are stated to the nearest degree Celsius. NOTE: The temperature setting on the automatic controller will not generally be the sterilization temperature, but a higher temperature within the sterilization temperature band. 14th October 2010 Slide 11

12 Key Terminology Reference measuring point (ISO) The point where the temperature sensor used for the operating cycle control is located The reference measurement point shall be selected in such a way that throughout the plateau period the temperature at this point correlates with the temperature in the usable space. The temperature relationship between the reference measurement point selected and the location identified as the coolest part of the usable space shall be determined. Chamber temperature The lowest temperature prevailing in the chamber. Active chamber discharge The controlled flow of air, or of air and condensate, from the chamber, through either a drain or a vent, such that the temperature of the discharge is at the temperature of the chamber The preferred locations for monitoring are as follows: a. in the drain, if it is active throughout the operating cycle; b. otherwise in a vent, if it is active throughout the operating cycle; c. otherwise in the coldest part of the usable chamber space. 14th October 2010 Slide 12

13 Key Terminology Equilibration time The period which elapses between the attainment of the sterilization temperature in the chamber and the attainment of the sterilization temperature in all parts of the load Note: EU GMP, Annex 1, Paragraph 92: Sufficient time must be allowed for the whole of the load to reach the required temperature before measurement of the sterilising time-period is commenced. This time must be determined for each type of load to be processed. Holding time (A.K.A. Exposure time) The period during which the temperature in all parts of the chamber and the load is held within the sterilization temperature band. It follows immediately after the equilibration time. Exposure time :The period for which the process parameters are maintained within their specified tolerances. NOTE: The holding time / exposure time follows immediately after the equilibration time. The extent of the holding time is related to the sterilization temperature. Plateau period The equilibration time plus the holding time 14th October 2010 Slide 13

14 Key Terminology Reference : HTM 2010 Part 3, Chapter 7, Figure 4. 14th October 2010 Slide 14

15 Key Terminology THIS IS NOT A REAL DEFINITION Settling down period The application of all thermometric acceptance criteria only from 60 seconds after the start of the plateau period time DO NOT APPLY THIS!!! A common misunderstanding Thermometric test for a small load during the plateau period the temperature measured above the test pack does not exceed the temperature measured in the active chamber discharge by more than 5ºC for the first 60 s and 2ºC for the remaining period. (Ref. HTM 2010 Part 3; (b)) 14th October 2010 Slide 15

16 Key Factors Steam Quality Air Removal Load Configuration 14th October 2010 Slide 16

17 Key Factors Steam Quality Key properties to be control Dryness >90% for normal porous loads >95% for metal loads. Superheat <25 o C of superheat Non Condensable Gases (NCG) <3.5% NCG Condensate Quality WFI quality when condensed 14th October 2010 Slide 17

18 Key Factors Air Removal Whilst a steam penetration test carried out on a periodic basis provides a very useful equipment control function, provision should be made to ensure adequate steam penetration occurs during every cycle. Air Detector Will detect: Poor vacuum performance High chamber leak rates High levels of NCG Various types Temperature type Pressure type Electronic Temperature/ Pressure correlation (Not appropriate) Set up and performance tested as part of validation. 14th October 2010 Slide 18

19 Key Factors Load Configuration Controlled loading patterns Repeatable layout and orientation. Consider: Condensate collection Occluded surfaces 14th October 2010 Slide 19

20 Validation Approach IQ, OQ ISO Generally references EN 285 in terms of tests to be performed. Commissioning HTM 2010 Tests defined within the document Reference : HTM 2010 Part 3, Chapter 4 Schedule of validation tests Table 2a Validation tests for porous load sterilizers and For each test specified the tables reference the relevant sections in which they are detailed. In relation to Table 2a Validation tests for porous load sterilizers, note exception in relation to specified PQ test. NOTE: Criticality of calibrations 14th October 2010 Slide 20

21 Validation Approach Performance Qualification (PQ): The process of obtaining and documenting evidence that the equipment will produce an acceptable product when operated according to process specification. Consists of tests designed to show that sterilization conditions are attained throughout a production load. Tests fall into two general categories: Thermometric tests Use accurate measuring equipment to monitor temperatures and pressures independently of the instruments fitted to the sterilizer. They provide the assurance that the temperature requirements for sterilization are met. Microbiological tests Microbiological tests are designed to show that sterilization conditions are attained where thermometric methods alone are not sufficient. 14th October 2010 Slide 21

22 Validation Approach Performance Qualification (PQ): Thermometric tests For PQ of porous loads the acceptance criteria for Thermometric test for a small load as specified in Section of HTM 2010 Part 3 are to be applied. HTM 2010 In sterilizers with an active air removal system thermometric tests for a small load are designed to demonstrate that the sterilizer is capable of removing air from a small load in which air from a near-empty chamber has been retained. Small load : A specified load, used in thermometric tests, to represent the minimum size and mass of load which the sterilizer is designed to process 14th October 2010 Slide 22

23 Validation Approach Performance Qualification (PQ): Thermometric tests ISO The validity of air dilution and steam penetration indirectly identified from the performance tests specified for installation qualification and operational qualification should be verified to be effective for a worst case sterilization load, loading configuration. EN 285 The test loads described in this European Standard are selected to represent the majority of loads for the evaluation of general purpose steam sterilizer for medical devices. However, specific loads (e.g. heavy metal objects or long and/or narrow lumen) will require the use of other test loads. 14th October 2010 Slide 23

24 Validation Approach Acceptance criteria The requirements of the automatic control test are met; During the plateau period the temperature measured above the load does not exceed the temperature measured in the active chamber discharge by more than 5ºC for the first 60 s and 2ºC for the remaining period; The equilibration time determined from the measured temperatures does not exceed 15 seconds for chambers up to 800 l and 30 seconds for larger chambers; The holding time determined from the measured temperatures is not less than that specified for the sterilisation temperature; 14th October 2010 Slide 24

25 Validation Approach Acceptance criteria During the holding time the temperatures measured in the active chamber discharge and in the load: are within the appropriate sterilization temperature band do not fluctuate by more than ±1ºC; NOTE: Incorrectly indicated as ±0.5ºC in some printed versions do not differ from one another by more than 2ºC; during the holding time: the indicated and recorded chamber temperatures are within 1ºC of the temperature measured in the active chamber discharge; the indicated and recorded chamber pressures are within 0.05 bar of the measured pressure; 14th October 2010 Slide 25

26 Validation Approach Performance Qualification (PQ): Microbiological tests HTM 2010 Microbiological testing may be necessary for any sterilizer where loading conditions cannot be validated solely by thermometric methods. ISO Data from which judgement is to be made should be established from temperature measurements supplemented by chemical indicators and/or biological indicators positioned in difficult-to-sterilize locations. 14th October 2010 Slide 26

27 Validation Approach Performance Qualification (PQ): Microbiological tests Biological Indicators (BIs) Ph.Eur BIOLOGICAL INDICATORS OF STERILISATION Steam sterilisation. The use of biological indicators intended for steam sterilisation is recommended for the validation of sterilisation cycles. Spores of Bacillus stearothermophilus (for example, ATCC 7953, NCTC 10007, NCIMB 8157 or CIP 52.81) are recommended. The number of viable spores exceeds per carrier. The D-value at 121 C exceeds 1.5 min. 14th October 2010 Slide 27

28 Validation Approach Performance Qualification (PQ): In principle, PQ is required for each loading configuration Min / Max approach acceptable PQ shall include a series of at least three consecutive exposures of the sterilization load to the sterilization process, which demonstrate compliance with the sterilization process specification and the reproducibility of the sterilization process. 14th October 2010 Slide 28

29 Application of F 0 concept HTM 2010 The F 0 method may be used for assessment, or control, of processes where difference in temperature is the only factor influencing the efficacy of the cycle. For example, it may be applied to the steam sterilization of aqueous fluids in sealed containers but it is not applicable to steam sterilization of porous loads where air removal is also a key factor and failure to achieve direct contact with Dry Saturated Steam can lead to failure, regardless of whether the required temperature was achieved within the load. ISO If a medical device is wrapped and/or non-condensable gas can be trapped in a part such as a lumen, tubing or crevice, F 0 calculated from chamber temperatures will not represent the lethality delivered and should not be used to judge the results of a sterilization process..in addition to the measurement of process parameters, steam penetration should be assured for each operating cycle, for example, by using an air detector fitted to the sterilizer 14th October 2010 Slide 29

30 Routine Monitoring and Control Periodic tests Must be subject to a schedule of periodic tests at various levels and intervals Daily, Weekly, Quarterly Yearly The yearly test schedule is essentially a revalidation schedule. It provides for performance requalification (PRQ) tests to confirm that data collected during performance qualification remain valid. Appropriate schedule: Reference HTM 2010 Part 3, Chapter 5, Table 4a Periodic tests for porous load sterilizers 14th October 2010 Slide 30

31 Routine Monitoring and Control Controls Roles and responsibilities clearly defined Personnel appropriately trained and assessed Stringent maintenance and calibration programmes Control of external contractors Change control Review and approval of each cycle Documented procedure in place 14th October 2010 Slide 31

32 Routine Monitoring and Control Controls Microbiological status of parts Validation and routine control of any cleaning procedures used on parts Control of the environment in which parts are assembled / wrapped The materials in which parts are wrapped and the manner in which they are wrapped Conditions under which parts are stored 14th October 2010 Slide 32

33 Summary Understand the fundamentals Be familiar with relevant standards Have appropriate quality steam Have a well defined and planned validation approach Implement rigorous controls 14th October 2010 Slide 33

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36 Questions? 14th October 2010 Slide 36