1 2 sterilisation-validationqualification
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This document discusses the validation of sterilization processes for sterile medicines. It defines sterility as a probability of less than 1 in 1 million of a container being contaminated. Sterilization methods discussed include moist heat, dry heat, ethylene oxide gas, radiation, and filtration. Validation of a sterilization process involves developing a protocol, calibrating instruments, developing sterilization cycles, and determining the necessary Fo value to achieve the required sterility assurance level based on the bioburden and most resistant organisms. Moist heat sterilization at 121°C for 15 minutes is provided as an example, which would achieve an Fo value of 15.
1 2 sterilisation-validationqualification
- 1. Manufacture of sterile medicines – 1 Sterilization - validation, qualification requirements Mrs Robyn Isaacson
- 2. Manufacture of sterile medicines – 2 Sterilization - Overview Objectives – Discuss definition of “Sterile” – Briefly describe sterilization methods – Describe approaches to be used for the validation of a sterilization process using Moist Heat as an example – Describe requirements for routine monitoring and control of sterilization – Review issues that are specific to other sterilization processes
- 3. Manufacture of sterile medicines – 3 Sterile Products - Overview • Certain pharmaceutical products must be sterile – injections, ophthalmic preparations, irrigations solutions, haemodialysis solutions • Two categories of sterile products – those that can be sterilised in final container (terminally sterilised) – those that cannot be terminally sterilised and must be aseptically prepared
- 4. Manufacture of sterile medicines – 4 Sterilization - Overview What is the definition of “sterile”? • Free from microorganisms In practice no such absolute statement regarding absence of microorganisms can be proven • Defined as the probability of 1 in a million of a container being contaminated (10-6 ) • This referred to as the Sterility Assurance Level (SAL) • Organisms are killed in an exponential fashion
- 5. Manufacture of sterile medicines – 5 Definition of “Sterile” MICROBIAL INACTIVATION Nt = Noe -kt 0 200 400 600 800 1000 1200 Time Noofsurvivingorganisms -2.00 -1.50 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 No remaining Log No remaining No remaining 1000 368 135 50 18 7 2 1 0 0 0 Log No remaining 3.00 2.57 2.13 1.70 1.26 0.83 0.39 -0.04 -0.47 -0.91 -1.34 0 1 2 3 4 5 6 7 8 9 10
- 6. Manufacture of sterile medicines – 6 Definition of “Sterile” Microbial Inactivation -3 -2 -1 0 1 2 3 4 1 2 3 4 5 6 Time LogNoofSurvivingOrganisms D-value - Time (or dose) required to reduce the population of organisms by 1 log (or 90%) D-Value Resistance of an organism is referred as its “D-value”
- 7. Manufacture of sterile medicines – 7 Definition of “Sterile” • A sterilization process must deliver a Sterility Assurance Level (SAL) of 1 in a million (10-6 ) • It is not possible to measure “10-6 ” • The required SAL can be achieved by applying a process that will reduce the number of organisms to zero and then apply a safety factor that will deliver an extra 6 log reduction
- 8. Manufacture of sterile medicines – 8 Definition of “Sterile” Example • For an initial bioburden of 102 the sterilization process will need to achieve an 8 log reduction in viable organisms • This will require 8 times the D- value (e.g. if the organism has a D value of 2 minutes then 8 x 2 = 16 minutes will be required to achieve an 8 log reduction and an SAL of 10-6 ) (Point Z) Microbial Death Curve -7 -6 -5 -4 -3 -2 -1 0 1 2 0 1 2 3 4 5 6 7 8 Time LogNoofSurvivors Y Z
- 9. Manufacture of sterile medicines – 9 Sterilization - Overview Commonly used methods of sterilization – Moist Heat – Dry Heat – Gas (Ethylene oxide) – Radiation (Gamma or Electron) – Filtration – Others - UV, Steam and formaldehyde, hydrogen peroxide
- 10. Manufacture of sterile medicines – 10 Moist Heat • Saturated steam • Common cycles: – 121°C for 15 minutes – 134°C for 3 minutes – Other cycles of lower temperature and longer time may be used (e.g. 115°C for 30 minutes) • Used for sterilization of: – terminal sterilization of aqueous injections, ophthalmic preparations, irrigation & haemodialysis solutions, equipment used in aseptic processing
- 11. Manufacture of sterile medicines – 11 Moist Heat • not suitable for non-aqueous/dry preparations • preferred method of sterilization
- 12. Manufacture of sterile medicines – 12 Dry Heat • Lethality due to oxidative processes • Higher temperatures and longer exposure times required • Typical cycles: – 160°C for 120 minutes – 170°C for 60 minutes – 180°C for 30 minutes – tunnels used for the sterilisation of glass vials may use much higher temperatures (300°) for a much shorter period
- 13. Manufacture of sterile medicines – 13 Dry Heat • Used for: – glassware and product containers used in aseptic manufacture, non aqueous thermostable powders and liquids (oils) • also used for depyrogenation of glassware (≥250°C) – (Pyrogens - substances found in cell wall of some bacteria which can cause fever when introduced into the body)
- 14. Manufacture of sterile medicines – 14 Ethylene Oxide Gas • Either pure or in mixtures with other inert gases • Requires presence of moisture • Complex process • Typical cycles: – 1-24hours – 25-1200 mg/L gas – 25-65°C – 30-85% relative humidity
- 15. Manufacture of sterile medicines – 15 Ethylene Oxide • Used for: – heat labile product containers – surface sterilization of powders • Adequate aeration to reduce toxic residues
- 16. Manufacture of sterile medicines – 16 Radiation • Gamma rays generated by Cobalt 60 or Caesium 137 radionuclides; or • Accelerated electrons from an electron generator • 25 kilograys (kGy) usual dose – dose dependent on bioburden (resistance of organisms not predictable) • process must be properly validated • used for: – dry pharmaceutical products – heat labile product containers • can cause unacceptable changes
- 17. Manufacture of sterile medicines – 17 Filtration • Removes organisms from liquids and gasses • 0.2 - 0.22 micron for sterilization • composed of cellulose esters or other polymeric materials • filter material must be compatible with liquid being filtered • used for bulk liquids, gasses and vent filters
- 18. Manufacture of sterile medicines – 18 Validation - Overview • Selection of sterilzation process must be appropriate for product – terminal sterilization is the method of choice – moist heat (autoclaving) is the most common process used for terminal sterilization – product must not be affected by heat – container/closure integrity must be established – items being sterilised must contain water (if sealed) or material must allow for removal of air and penetration of steam for steam (moist heat) sterilization
- 19. Manufacture of sterile medicines – 19 Validation - Protocol Requirements for Moist Heat Sterilization Other processes follow similar requirements • Validation protocol should include the following details for each sterilization process – process objectives in terms of product type, container/closure system, SAL required – specifications for time, temperature, pressure and loading pattern – description of all equipment and support systems in terms of type, model, capacity and operating range
- 20. Manufacture of sterile medicines – 20 Validation - Protocol Moist Heat continued: – performance characteristics of all equipment e.g. pressure gauges, valves, alarm systems, timers, steam flow rates/pressures, cooling water flow rates, cycle controller functions, door closure gasketing and air break systems and filters – methodology for monitoring performance of equipment and the process and labatory testing methodology – personnel responsible for all stages and final evaluation (should have experience and necessary training and be authorized)
- 21. Manufacture of sterile medicines – 21 Validation - Calibration • Laboratory testing should be performed by a competent laboratory, methodology should be documented • All instruments must be calibrated e.g. – temperature recorders and sensors – thermocouples – pressure sensors for jacket and chamber – timers – conductivity monitors for cooling water – flow metres for water/steam – water level indicators when cooling water is used – thermometers including those for thermocouple reference, chamber monitoring and laboratory testing
- 22. Manufacture of sterile medicines – 22 Validation - Calibration • Indicators should be calibrated – physical and chemcial indicators should be tested to demonstrate acceptable response to time and temperature – biological indicators should be tested for count and time/temperature exposure response • for commercial indicators - test certificate with count and D-value and exposure response should be available. Results acceptable if verified “in house” periodically. • In house indicators must be fully characterized (D- value, identification) and appropriate for sterilization process All indicators should be appropriately stored and within expiry
- 23. Manufacture of sterile medicines – 23 Validation - Cycle Development • Concept of Fo – Lethality factor equivalent to time at 121°C • 1 minute at 121°C is equivalent to Fo of 1. • Lethality can accumulate during heat up and cool down phases Typical temperature profile of a heat sterilization process What would be the Fo of a cycle at 121°C for 15 minutes?
- 24. Manufacture of sterile medicines – 24 Validation - Cycle Development • Fo is calculated using the following equation: Fo = ΔtΣ10(T-121/Z) where: • “Δt” is the time interval between measurements of temperature (T) • “T” is the temperature of sterilised product at time (t) • “Z” is a temperature coefficient which measures the number of degrees required to change the D-value of an organism by 1 log
- 25. Manufacture of sterile medicines – 25 Validation - Cycle Development • The minimum Fo required by a sterilzation process is related to the resistance of the bioburden (D-value) Fo = D121 (LogA - Log B) where: • “D121” is equal to the time at 121°C to reduce the population of the most resistant organism in each product container by 90% (or 1 log) • “A” is the number of microoganisms per container • “B” is the maximum acceptable probability of survival (Sterility Assurance Level , 10-6 )
- 26. Manufacture of sterile medicines – 26 Validation - Cycle Development • Two approaches to sterilization – Overkill – Probability of survival • Overkill approach used when the product can withstand excessive heat treatment without adverse effects – Cycle should deliver an Fo of at least 12 • This will achieve a 12 log reduction of microorganisms with a D-value of 1 minute (Assuming each product unit contains 106 organisms a 12 log reduction will result in 10-6 organisms per unit or probability of survival (SAL) of 1 in a million) (Normal bioburden is usually much lower and the organisms normally much less resistant than this)
- 27. Manufacture of sterile medicines – 27 Validation - Cycle Development Biological Indicators • device consisting of a known number of microorganisms, of a known resistance to a particular sterilization process in or on a carrier and enclosed in a protective package. – Organisms are in the form of endospores (not vegetative state) as these are most resistant to sterilization Organism D-Value Geobacillus stearothermophilus (most common) 1 - 2.8 Bacillus coagulans 0.3 Clostridium sporogenes 0.8 – 1.4 Bacillus atropheus 0.5
- 28. Manufacture of sterile medicines – 28 Validation - Cycle Development Spore Strips - a narrow strip of fibrous paper impregnated with a bacterial spore suspension contained in a glassine envelope Spore Dots - Circular pieces of fibrous paper impregnated with the spore suspension Spore Suspensions - pure spore suspension of the desired challenge organism which can be inocluated onto the surface of a material Self contained units containing spore strips or suspensions and the media in which they are to be incubated (simple/convenient to use)
- 29. Manufacture of sterile medicines – 29 Validation - Cycle Development • Probability of Survival approach used used for heat labile products The process is validated to achieve a destruction of the presterilization bioburden to a level of 100 (Point Y), with a minimum safety factor of an additional six-log reduction (Point Z) Determination of the minimum Fo required is based on the bioburden and its heat resistance What Fo would be required for a bioburden of 102 (100) if D-value was 1?
- 30. Manufacture of sterile medicines – 30 Validation of Sterilization Basic Principles • Installation Qualification (IQ) – Ensuring equipment is installed as per manufacturer’s specification • Operation Qualification (OQ) – Ensuring equipment, critical control equipment and instrumentation are capable of operating within required parameters • Performance Qualifcation (PQ) – Demonstrating that sterilizing conditions are achieved in all parts of sterilization load – Physical and microbiological
- 31. Manufacture of sterile medicines – 31 Validation - Equipment Installation Qualification • Ensuring equipment is installed as per manufacturer’s specification – considerations for new and existing equipment – specifications for the type of autoclave, construction materials, power supplies and support services, alarm and monitoring systems with tolerances and accuracy requirements – for existing equipment documented evidence that the equipment can meet process specifications
- 32. Manufacture of sterile medicines – 32 Validation - Equipment Operational Qualification • Ensuring equipment, critical control equipment and instrumentation are capable of operating within required parameters • Three or more test runs which demonstrate – controls, alarms, monitoring devices and operation indicators function – chamber pressure integrity is maintained – chamber vacuum is maintained (if applicable) – written procedures accurately reflect equipment operation – pre-set operation parameters are attained for each run
- 33. Manufacture of sterile medicines – 33 Validation - Performance Performance Qualification • Demonstrating that sterilizing conditions are achieved in all parts of sterilization load • Physical and microbiological Physical • Heat distribution studies on empty chamber – maximum and minimum cycle times and temperatures – to identify heat distribution patterns including slowest heating points – mulitple temperature sensing devices should be used (thermocouples) – location of devices should be documented and ensure that heat distribution is uniform
- 34. Manufacture of sterile medicines – 34 Validation - Performance Performance Qualification - Physical (2) • Heat distribution of maximum and minimum chamber load configurations – multiple thermocouples throughout chamber (not inside product containers) to determine effect of load configuration on temperature distribution – temperature distribution for all loads using all container sizes used in production should be tested – position of thermocouples should be documented – Slowest to heat/cold spots in each run should be documented, inlcuding the drain – repeat runs should be performed to check variability – temperature distribution profile for each chamber load configuration should be documented
- 35. Manufacture of sterile medicines – 35 Validation - Performance Performance Qualification - Physical (3) • Heat penetration studies to detect the maximum and minimum temperature within all loads – all parts of each load must be on contact with steam – need to determine lowest and highest temperature locations and slowest and fastest to heat locations (measured inside product containers) – need to consider all variables such as container size, design, material, viscosity of solution and fill volume. Container with maximum fill volume and slowest to heat solution should be used – maximum and minimum load configurations for each sterilization cycle using routine cycle parameters
- 36. Manufacture of sterile medicines – 36 Validation - Performance Performance Qualification - Physical (4) • Heat penetration (2) – May be necessary for container mapping for larger volumes - cold spot then used for penetration studies – Need to consider effects of packaging e.g. overwrapping – Three runs performed once cold spots have been identified to demonstrate reproducibility
- 37. Manufacture of sterile medicines – 37 Validation - Performance Performance Qualification - Microbiological • Biological challenge studies – used when Probability of Survival approach is used – may not be necessary when cycle is > 121°C for 15 minutes (except US and Australia) – biological indicators (BI) containing spores of Geobacillus stearothermophilus are most commonly used (considered “worst case”). BIs containing other organisms may be used – performance studies based on product bioburden require a considerable amount of work – indicators should be placed throughout the load, adjacent to thermocouples, at “cold spots” and slowest to heat locations (identified during heat penetration studies) – any growth is unacceptable unless processing errors demonsrated
- 38. Manufacture of sterile medicines – 38 Validation - Performance • Validation report must demonstrate requirements in Validation protocol have been met, any deviations must be justified • Requalification must be repeated on an annual basis (usually one run is acceptable) • Any changes or modifications must be evaluated – may just require requalification – any changes to loading patterns, new container/closure systems or cycle parameters require full validation
- 39. Manufacture of sterile medicines – 39 Routine Production Issues considered for routine production • Manufacturing environment should be controlled • Procedures in place to minimize the pre- sterilization bioburden – bioburden limits specified (although not so important when “overkill” cycle used) • Time between filling and sterilization should be specified • Integrity of container/closure system should be periodically verified • Periodic leak testing of chamber (if vacuum is part of cycle)
- 40. Manufacture of sterile medicines – 40 Routine Production • Cooling water should be sterile • Differentiation between sterilized and not-yet sterilized product – Physical separation (double ended autoclave) – Labelling and use of visual indicators (e.g autoclave tape) • Periodic testing of containers to verify integrity of container/closure system • Quality of steam should be defined and periodically tested for contaminants
- 41. Manufacture of sterile medicines – 41 Routine Production • Each sterilization cycle must be monitored – temperature, time and pressure recorded – temperature recorder independent from cycle controller – second independent temperature recorder – drain temperature should be recorded – chemical and biololgical indicators (if applicable) • Sterilisation cycle records should form part of batch records
- 42. Manufacture of sterile medicines – 42 Other Sterilization Processes Sterilization using other processes should follow a similar approach as that described for moist heat – Validation protocol – Equipment calibration – Determining the process that will deliver the desired SAL (10-6 ) – IQ, OQ, PQ – Requirements for routine monitoring and control
- 43. Manufacture of sterile medicines – 43 Other Sterilization Processes Dry Heat – Should have air circulation in the chamber – Positive pressure in the chamber to prevent entry of non-sterile air – HEPA filtered air supplied – Biological indicators containing Bacillus atropheus (if used) • removal of endotoxin is usually sufficient – When removing pyrogens need to validate process using challenge tests
- 44. Manufacture of sterile medicines – 44 Other Sterilization Processes Radiation – Usually performed by contracting service (need to ensure validation status, responsibilities) – Based on bioburden of product being sterilised • Biological indicators may be used as additional control but may not be as resistant as naturally occuring bioburden – Method defined in International Standard ISO 11137
- 45. Manufacture of sterile medicines – 45 Other Sterilization Processes Radiaton (2) – Correct dose of radiation (~25 kGy) received by all products (measured with dosimeters) • quantitative measurement • number, location, within calibration time-limit – Radiation sensitive colour discs applied to packaging – procedures to distinguish irradiated and non- irradiated materials – Variation in density of packaging should be addressed during validation
- 46. Manufacture of sterile medicines – 46 Other Sterilization Processes Gasses and Fumigants – e.g. ethylene oxide, hydrogen peroxide vapour – Only when no other method is suitable – Must demonstrate that process does not adversely affect product – Packaging must be able to permit ingress of gas and humidity – Ensure product load is adequately heated and humidified prior to sterilization (called “conditionning”) • need to take into account validation performed in summer or winter
- 47. Manufacture of sterile medicines – 47 Other Sterilization Processes Gasses and Fumigants (2) – Temperature distribution is acceptable – Concentration of sterilant gas is sufficient – Use of biological indicators is important (Bacillus atropheus) – Half cycles • If cycle of half normal time destroys biological indicators (106 organisms), double time will achieve SAL of 10-6 – Aeration • Ventilated conditions • Defined limits of residuals • Process included in validation – Safety and toxicity issues considered
- 48. Manufacture of sterile medicines – 48 Useful Publications • ISO/EN 17665 - Sterilization of health care products - Moist Heat (Parts 1 and 2) • ISO/EN 11135 - Sterilization of health care products - Ethylene Oxide (Parts 1 and 2) • ISO/EN 11137 - Sterilization of health care products - Radiation (Parts 1,2 and 3) • “Validation of Moist Heat Sterilization Processes: Cycle Design, Development, Qualification and ongoing Control. PDA Technical Report No. 1 Revised 2007
- 49. Manufacture of sterile medicines – 49 Questions?