Transcript Chapter 8 Disinfection、sterilization and validation

Chapter 8 Disinfection、
sterilization and validation
8.1 Disinfection and sterilization
• 8.1.1 Microorganism
– Microorganisms and Pathogenic microorganisms
• The microorganisms are tiny, simple-structure but
diverse organisms.
Non-cellular microorganism
Prokaryotes
Eukaryotes
• Most of the microorganisms are vital to humans, animals
and plants.
• Only a small number of microorganisms, known as
pathogenic microorganisms, can cause human, animal
and plant diseases.
• Pathogenic microorganisms invade the host, interact
with the host’s defense systems and result in pathology,
a process called infection.
•
Environment for microbial growth
–
Bacterial growth and reproduction requires
sufficient nutrition, appropriate temperature,
humidity and suitable environment (such as pH
value, etc.).
Temperature
Figure 6.1
Psychrotrophs
Figure 6.2
The Requirements for Growth:
Physical Requirements
• pH
– Most bacteria grow between pH 6.5 and 7.5
– Molds and yeasts grow between pH 5 and 6
– Acidophiles grow in acidic environments
The Requirements for Growth:
Physical Requirements
• Osmotic Pressure
– Hypertonic environments, increase salt or sugar,
cause plasmolysis
– Extreme or obligate halophiles require high
osmotic pressure
– Facultative halophiles tolerate high osmotic
pressure
The Requirements for Growth:
Physical Requirements
Figure 6.4
The Requirements for Growth:
Chemical Requirements
• Carbon
– Structural organic molecules, energy source
– Chemoheterotrophs use organic carbon
sources
– Autotrophs use CO2
The Requirements for Growth: Chemical
Requirements
• Nitrogen
– In amino acids, proteins
– Most bacteria decompose proteins
– Some bacteria use NH4+ or NO3
– A few bacteria use N2 in nitrogen fixation
• Sulfur
– In amino acids, thiamine, biotin
– Most bacteria decompose proteins
– Some bacteria use SO42 or H2S
• Phosphorus
– In DNA, RNA, ATP, and membranes
– PO43 is a source of phosphorus
The Requirements for Growth: Chemical
Requirements
• Oxygen (O2)
obligate
aerobes
Faultative
anaerobe
s
Obligate
anaerobes
Aerotolerant Microaerophile
anaerobes
s
8.1.2 Concept of disinfection and
sterilization
• 1. Disinfection
– can kill pathogenic micro-organisms, but may not kill the
bacterial spores and non-pathogenic micro-organisms.
– use disinfectant
• At standard concentration, disinfectant can only kill bacterial
vegetative forms
• 2. Sterilization
– a method to kill all microorganisms,
• 3. Asepsis
– the practice to reduce or eliminate contaminants (such as
bacteria, viruses, fungi, and parasites) from entering the
operative field in surgery or medicine to prevent infection
• 4. Pyrogen and its removal
– A pyrogen is a substance that induces fever.
– can be either internal (endogenous) or external (exogenous)
to the body.
• Exogenous pyrogen , are toxins and microorganisms.
– To remove pyrogen from objects usually
requires :
• dry heat at 180℃ for more than 2 hours
• Or dry heat at 250℃ for more than 30 minutes
8.1.3 Basic methods of disinfection and
sterilization
• 1. Physical methods of disinfection and sterilization
– Heating: the most important disinfection method
– electromagnetic radiation,
– Filtration
– ultrasonic waves.
• Heat disinfection and sterilization can be divided
into two major categories :
– damp heat
• Damp heat sterilization required lower temperature and
shorter time compared with dry heat sterilization method
• Pasteurization , Boiling , High-pressure steam
– dry heat
• to sterilize using high temperature air with relative humidity
less than 20%
• Combustion , Cauterization , Burning , Hot air oven ,
• 2. Chemical disinfection and sterilization
– When chemical substances penetrate into bacteria,
they will denature bacterial protein, decrease the
activity of bacterial enzyme, inhibit bacterial growth
and metabolism, or damage the structure of cell
membrane, change membrane permeability.
• According to the mechanisms of disinfection, chemical
disinfectants can be divided into :
– Coagulate and denature bacterial protein,
• such as phenols (high concentration), alcohols, heavy-metal salts
(high concentration), acids and alkalis, aldehydes
– Interfere with bacterial enzyme system and metabolism.
• such as certain oxidants, heavy-metal salts (low concentration).
– Damage cell membranes of bacteria,
• such as phenols (low concentration), surfactants.
• They can lower surface tension of bacterial cell membranes and
increase membrane permeability.
8.2 validation
• 8.2.1 Importance of validation
– 1. Concepts and importance of validation
• refers to establishing documented evidence that a process or
system, when operated within established parameters, can
perform effectively and reproducibly to produce a medicinal
product meeting its pre-determined specifications and quality
attributes.
• Documents of validation should at least include
the followings:
–
–
–
–
《General plan of validation》,
《Plan of validation》,
《Validation report》
《Summary of validation》.
• Drug manufacturers pay great attention to
validation for three reasons:
– Governmental regulation: FDA ,SFDA mandatory
requirements
– Guarantee of the product quality:
– Reduction of initial costs:
• 2. Classification of validation
– Prospective validation.
• The purpose of prospective validation is to verify whether the
changes of operating parameters meet the changes of
independent freezing-drying variables and product quality.
– Concurrent validation
• is conducted with the intention of ultimately distributing
product manufactured during the validation study.
– Retrospective validation
• is the validation of a process based on accumulated historical
production, testing, control, and other information for a
product already in production and distribution.
– Process validation:
• Process validation is establishing documented evidence
which provides a high degree of assurance that a specific
process will consistently produce a product meeting its predetermined specifications and quality characteristics.
8.3 The cleaning-in-place, sterilization-inplace and validation
• 8.3.1 Cleaning-in-place and confirmation of freezedrying system
– 1. Cleaning in place(CIP)
• Cleaning in place: generally, washing with reverse osmosis(RO)
water for 5 min, followed by water for injection(WFI) for 5 min.
– 2. Validation of Cleanness
• check the cleaned surface by wiping test
• 8.3.2 Sterilization in place and confirmation
of freeze-drying system
– 1. Sterilization in place (SIP)
• At present, saturated steam sterilization method is
widely used in freeze-dryer.
– 2. Confirmation of SIP
• Thermocouple verification
• Temperature profile test
• Biological indicator challenge test
8.4 process validation of freeze-drying
• 8.4.1 Validation protocol
– 1. General validation protocol
• are the documents with tests and instructions that are
executed for a process, equipment validation or analytical
method validation etc
• A complete process validation includes the fllowing:
– the public project confirmation
– the manufacture environment confirmation,
– the mechanical device's installment and the operating
condition confirmation,
– the operating procedure confirmation,
– the producing technique and the product confirmation.
– 2. Process validation document of freeze-drying
• The process validation document of freeze-drying include
–
–
–
–
–
the illustration of equipment operating principle,
installation condition,
operating condition,
principle of control system
the related public project and service facility.
• The validation protocol should include
– Standard Operating Procedure(SOP)、
– data acquisition method
– the data processing method.
• The document should also include
–
–
–
–
–
–
–
–
the test condition and result for the equipments,
the freezing rate with/without load,
the lowest temperature,
the precision of the shelf temperature、
the pressure of the freeze-dryer,
the precision of the vacuum,
the condition to get the limited vacuum,
the efficiency of sterilization.
8.5 Validation of technical process and the
evaluation of validation
• 8.5.1 Technical process of freeze-drying
– The modern freeze-drying is mainly used in the
production of biological agents and antibiotics
with unstable properties.
– A typical lyophilized process is described in Fig.
8-3.
• The validation of technical process includes
– the prospective validation of the new product
– and retrospective validation of the old products.
– There are many parameters in the lyophilization
technical process, but it is not necessary to invole all
parameters in the validation.
– It is very important to chose some significant
parameters for validation, especially those that has
significant impact on the quality of the final products.
– The weak links of the equipment can be found by this
valiation test.
– The technical process validation documents should
include analysis and evaluation of the data of batch
production process and the quality of final product.
• Main contents of the technical process
validation:
– 1. Process water and freezing rate
• Process water
– the composition of process water will affect the structure of ice
crystals and the rehydration performance of the preparation.
– There is a supercooling in the freezing process of the liquid
medicine.
• Freezing rate
– The change of capacity will affect the freezing rate.
– the optimum freezing rate for lyophilized preparation is
depend on the its characteristics.
– 2. Preparation temperature and drying time
• Though the preparation temperature can be measured
directly, it is controlled indirectly by temperature change
of the shelf.
• The validation of the preparation temperature is suggested to
be done as follows:
– The preparation temperature in sublimation drying process
– The determination of the preparation temperature and end of
drying in the secondary drying process
– Effect of vacuum control pricison on preparation
– Validation of vacuum condenser temperature
8.5.2 Evaluation and confirmation of the
validation results of the freeze dried products
• Products validation in the freeze drying technical
validation is a trial production under special monitoring
conditions.
• The validation of the freeze dried products usually
includes the following
• 1. Confirmation of freeze drying technical
parameters
• 2. Confirmation of the quality of lyophilized
preparation
–
–
–
–
Appearance and redydration
Moisture
Potency
Product stability testing
• 3. Evaluation and confirmation of validation results
– Factors influencing the properties of lyophilized preparation
– Processing methods for unmatching acceptance criterion
8.6 Daily Monitoring, Revalidation and
Retrospective Validation
• 8.6.1 Daily monitoring of freeze drying technical
process
– The public facility as water, electricity, air, and vapor may
not be as stable as the requirement in very long period of
freeze drying.
– In addition, the unstable operation of the freeze-drying
equipment may induced by wear and tear of parts.
8.6.2 Revalidation of freeze drying technical process
• When the following circumstances occurred,
some contents of the validation should be
revised according to the validation plan to
confirm adaptation and reproducibility of the
manufacturing process.
– 1）Equipment and devices have great change or
major maintaince;
– 2）Changes of manufacturing techniques, testing
methods；
– 3） In the daily validation, such important techncal
parameters are unformal, public facilities or the
quality of preparation are abnormal and so on.
8.6.3 Retrospective validation
• analyzes a large number of recorded data and compared with the
verification test results.
• It is emphasized that the original manufacturing record is not only an
document of evidence but also the technical information.
• finds a more suitable validation plan and the clue of improving
process conditions by a comparative analysis of the recorded data in
the original manufacturing process.
• THE END!