1 Overview
Sterile
drugs refers to the statutory drug standards listed in the preparation
of sterile test items and bulk drugs, generally including injections,
sterile raw materials and eye drops and so on . Strictly
speaking, aseptic drugs should contain absolutely no living
microorganisms. However, because of the limitations of the current
testing methods, the concept of absolute asepticity can not be applied
to the sterility assessment of the entire batch of products. Therefore,
the currently used " sterile " concept, is the sense of probability " sterile " . The
sterility characteristics of a group of pharmaceuticals can only be
characterized by the presence of living microorganisms in the batch of
medicines as low as an acceptable level, Sterility Assurance Level (SAL ). This
probabilistic sterility assurance depends on a reasonable and validated
sterilization process, a good sterility assurance system and a strict GMP management in the production process .
Sterile drugs usually sterilization methods can be divided into: 1 ) wet heat sterilization; 2 ) dry heat sterilization; 3 ) radiation sterilization; 4 ) gas sterilization; 5 ) sterilization filter. According to the process is divided into the final sterilization process ( sterilizing process ) and aseptic processing ( aseptic processing ). The
final sterilization process refers to the process of completing the
proper sterilization of the final sealed product, and the sterile
preparation thus produced is referred to as the final sterile sterilized
product. Both wet heat sterilization and radiation sterilization belong
to this category. Aseptic
process refers to the method of producing aseptic drugs by aseptic
processing under aseptic environment conditions. Sterile filtration and
aseptic production all belong to aseptic production process. Part or all of the processes using aseptic production process of the drug known as non-sterile sterile drugs. Based on the current status of sterile drug sterilization / sterilization processes ,
this guideline mainly discusses wet heat sterilization and aseptic
manufacturing processes commonly used in the manufacture of injectables
and sterile APIs. The
principles of the wet heat sterilization process validation include
screening and study of sterilization conditions, physical confirmation
of wet heat sterilization, bio-indicators to confirm content; aseptic
production process validation include aseptic packaging, sterilization
filtration, Medium simulation filling, validation of filtration system
verification content.
The
end-to-end sterilization process and the aseptic manufacturing process
are essentially different from the aseptic process of a product and
therefore determine the vast difference in the minimum level of aseptic
assurance that a product produced from both types of process should
achieve. Sterile products terminally sterilized sterility assurance level of residual microbial contamination probability ≤10 -6 , sterility assurance level of non-sterile products terminally sterilized should reach at least 95% confidence limit pollution probability of <0 .1="" font=""> . Thus,
the probability of non-end-sterilized sterile products microbial
contamination is much higher than the final sterile products, in order
to minimize the probability of non-end-sterile products contaminated
microorganisms to encourage enterprises to use production in isolation
And other advanced technology and equipment.
Based
on the concept of quality-based drug research and development and
quality control, in order to ensure that the level of sterility
assurance of sterile pharmaceuticals meets the requirements, R & D
personnel should select suitable sterilization methods according to the
characteristics of pharmaceutical products in the process of product
development and systematically Assess the impact of various stages of
production and various factors on the level of sterility assurance,
verify the reliability of the sterilization process according to the
level of risk and the probability of occurrence of risk, and verify the
content, scope and batch number etc. The complexity of the process and
the product as well as the manufacturing enterprises experience of
similar processes and other factors. Only
in the research and development through systematic and in-depth
research and verification, access to reliable sterilization process, and
in the daily production of the strict implementation of the process, in
order to truly ensure that each batch of sterile drug assurance level
in line with the expected requirements. Of
course, the entire life cycle of pharmaceuticals, as the
characteristics of the production of pharmaceutical products and
production processes more and more understanding of the more and more
sterilization process is also constantly improving, then it will involve
the change How to verify the process of the issue, the guidelines also
apply to this situation.
As sterilization / sterilization process
validation work carried out in our country is not long, the foundation
is not solid, it is inevitable in the actual work will encounter a lot
of unpredictable problems, so the guidelines are only a general
principle of drug development Should proceed from the objective laws of
drug development, specific problems of specific analysis, if necessary,
according to the actual situation using other effective methods and
means. At the
same time, as a phased product, these guidelines are bound to be
revised and improved as drug researchers and evaluators deepen their
understanding of the sterilization process research and validation.
2 preparation wet heat sterilization process
2.1 wet heat sterilization process research
2.1.1 wet heat sterilization process to determine the basis
The choice of sterilization process is generally in accordance with the decision tree sterilization process (see Annex 1 ), moist heat sterilization process is the first consideration in the decision tree sterilization process. Wet
heat sterilization method is the use of high-pressure saturated steam,
hot water spray and other means to microbial protein, nucleic acid
denaturation and kill microorganisms. While high temperatures kill microorganisms, they may also have an impact on the quality of the drug. If the product can not tolerate moist heat sterilization, you need to consider the use of aseptic production process. Therefore,
the investigation and determination of the drug sterilization process,
the first is to examine whether its use of wet heat sterilization
process, can withstand the heat sterilization temperature.
Currently there are two main methods of heat and humidity sterilization: over kill ( F 0 ≥ 12 ) and residual probability ( 8 ≤ F 0 <12 font=""> ). With other F 0 value of less than 8 terminal sterilization conditions of the process, you should follow the aseptic production process requirements.
These
two kinds of wet heat sterilization methods can be used in the actual
production, the specific choice of which sterilization method depends
largely on the thermal stability of the sterilized product. Whether
the drug can withstand the high temperature of the heat and moisture
sterilization process is closely related to the environment in which the
active ingredient exists in addition to the chemical nature of the
active pharmaceutical ingredients. Therefore, during the initial process
design, the thermal stability of the drug needs to be integrated
Analysis to determine whether the use of wet heat sterilization process.
2.1.1.1 chemical composition of the active ingredient characteristics and stability
By
analyzing the chemical structure of the active ingredient, the
stability of the active ingredient can be initially judged. If the
active ingredient structure contains some heat-labile structural groups,
the thermal stability of the main ingredient may be poor. On
this basis, the stability of the active ingredient should be further
studied by designing a series of compulsory degradation tests to confirm
that it is possible to understand the degradation reaction of the
active ingredient under various conditions in order to take the Sexual
measures to protect the product to use wet heat sterilization process.
2.1.1.2 Prescription technology research
Based
on the study of the structural characteristics and the stability of the
active ingredients, the optimization of the prescription process can be
targeted.If the active
ingredient is susceptible to oxidation, it may be necessary to consider
the need to remove the oxygen during the process and to use a
nitrogen-free process or to add suitable antioxidants to the
formulation; if the stability of the active ingredient is related to pH , Through research to find the most conducive to the stability of the pH value of the main component , of course, need attention at this time in the clinical treatment of pH can
accept; if the main component because of the presence of certain
impurities affect the stability, you need through appropriate means
Remove the related impurities; if the main component in a solvent system
less stable, you need to consider replacing the solvent system, this
time also need to consider the choice of solvent system in clinical
applications can be accepted; wet heat sterilization The combination of
different sterilization temperature and sterilization time has different
requirements on the stability of the product. The tolerance of the drug can be determined by adjusting the sterilization time and sterilization temperature on the basis of assuring the required SAL Wet heat sterilization process.
In
short, the need to pass all aspects of research, so that drugs can be
used as much as possible moist heat sterilization process. Only
when both theory and practice demonstrate that the active ingredient
can not withstand the heat and humidity sterilization process even after
the adoption of various techniques and techniques are available, can
aseptic production processes with lower sterility assurance be selected.
2.1.3 Stability Study
Regardless of the design method used, stability studies of the final sterilized product are required. Tests
that examine the effect of the final sterilization procedure on the
stability of a product's properties may include product degradation,
content, pH , color, buffering capacity, and other quality characteristics of the product.
When
sterilized, the effect of killing the microorganisms and the
degradation of the active ingredient both accumulate over time and
temperature. This means that heating and cooling changes will affect the stability of the product, while affecting the killing effect. Therefore, the stability study samples are best selected among the most demanding sterilization conditions, such as: Stability testing can be performed using products that have been sterilized at the point of maximumF0 in the heat penetration test to ensure that Quality can still meet the requirements.
2.1.2 over kill method of technology research
In
general, there is less information on the bioburden of the initial
stage of sterilization and daily monitoring of the sterilized product
required for the over-kill method than the residual probability method,
but the over-kill requires a relatively large amount of thermal energy
and the consequence is extinguished The possibility of degradation of
the strain increases.
The
goal of overkill is to ensure that a certain level of sterility
assurance is achieved, regardless of the number of initial bacteria in
the product being sterilized and its heat resistance. The
biocidal and thermostability of the over kill method hypothesis is
higher than the actual number, whereas most microorganisms are
relatively low in heat resistance. It is seldom found that the naturally
occurring microorganism has a D 121 ° C value greater than 0.5 minutes. Therefore,
the over-kill sterilization program can theoretically kill the
microorganisms completely, thus providing a high sterility assurance
value. Since
this method has made the worst assumptions regarding bioburden and heat
tolerance, from a technical point of view, there is not much need for
initial bacterial monitoring of the sterilized product.
However, this does not mean that pollution can be completely uncontrolled in the production process. Only
from the perspective of controlling the pyrogen should also follow the
process of health norms to control microbial contamination of products. If the actual production strictly follow follow GMP requirements, this can be achieved.
2.1.3 residual probability method of technology research
The
residual probabilistic method requires much more information than the
overkill method, including information on the initial stages of
production of the sterilized product as well as on the normal production
stages, the indicator bacteria (tests showing strong heat resistance to
the sterilization process Bacteria) and biological load information. Only after such valuable information has been accumulated can a thermostable sterilization procedure be established that has a lower F 0 than the over kill method and the sterility assurance level of the product will not be reduced. Use of lower heat sterilization procedures are more conducive to the stability of the drug, so that the product is extended. It is for this reason that the residual probability method is more suitable for those end-products with poor heat-resistance.
In
general, over-kill methods may not be used to sterilize thermolabile
drugs and a sterilization program needs to be designed to properly kill
the bioburden without causing unacceptable degradation of the product. In this case, validation of the sterilization procedure requires the study of the bioburden and heat resistance of the product. According to the following formula can be more clearly illustrate this point:
Sterility Assurance Value = F 0 / D - lgN 0
Among them, the sterility assurance value is the negative logarithm of SAL ,N 0 is the total number of contaminated microorganisms in the product at the beginning of sterilization, and D is the heat resistance parameter of the contaminated microorganisms. Therefore, the sterility assurance fungus value and F 0 , N 0, D are closely related.
2.1.3.1 Pre-sterilization bioburden control
In
addition to the need to focus on the sterilization process itself,
end-of-life products using residual probabilities require some
appropriate means to monitor and control the bioburden of the drug prior
to sterilization. Specific
measures usually include the number of microorganisms before
sterilization and heat resistance monitoring, liquid filtration, the
control of process parameters and so on.
Monitoring of microbial contamination levels prior to sterilization will be elaborated in the following sections. Product
filtration in the terminal sterilization products only as an auxiliary
control, but in the process of determining the process, the filter
should also be on the pore size, material, the filter cycle of the
necessary screening. In
terms of process parameter control, due to the nature of the
microorganism, it usually multiplies during the placement of the
medicinal solution. In particular, some nutritional injections such as
glucose injection, compound amino acid injection and the like are more
environmentally friendly for the growth of microorganisms and Therefore,
process screening and validation should be carried out to determine the
longest time before the solution is formulated to be filtered, and
after filtration to sterilization, and the key process parameters such
as batch size and production cycle of the product should be determined
accordingly.
2.1.3.2 Pre-sterilization microbial contamination monitoring
Before
sterilization, the monitoring of the level of microbial contamination
should be sampled during the normal production process and cover the
entire production process. The sampling design should select the largest
and most representative samples in the production process, and take
full account of the product from potting to sterilization Before the
placement time. In
general, if filling lasts for a period of time, samples may be taken
separately from the start, middle, and end of each batch of product. Pollution levels can be checked by the following method: first with sterile 5% Tween full wet 0.45um filter, and then quantitative filter liquid, the filter is moved to nutrient agar plate, at 30 ~ 35 ℃ culture 3 to 7 days, counting.
Isolation of contaminated bacteria need to check the heat resistance. The heat resistance of the contaminated bacteria can be examined by the following method: First, a 0.45 μm membrane filter is thoroughly wetted with sterile 5% Tween ,
and then filtered to monitor the sample of the solution taken from the
contamination level, and the membrane is then removed A test tube
containing a sterile product to be monitored is boiled in a boiling
water bath for about 30 minutes and then incubated in thioglycolic acid broth at 30-35 ° C to see if there is any growth of thermotolerant bacteria.
When
the heat resistance test found that there is contamination of the
liquid heat-resistant bacteria contamination, it can be time-boiled it
with known bio-indicators of heat resistance to be compared, if
necessary, re-test the heat-resistant bacteria D value ( Details of the D value of the specific detection methods, see Annex 2 ), and then according to the sterilization F 0 value and the number of contaminated bacteria and heat resistance of the product to evaluate the sterility. When
the level of microbial contamination of products exceeds the standard,
the identification of contaminated bacteria should be carried out to
investigate the source of contaminated bacteria and adopt corresponding
corrective measures.
2.2 wet heat sterilization process validation
Humidity
and heat sterilization process is generally divided into physical
verification and biological verification of two parts, physical
verification, including heat distribution, thermal penetration test,
biological verification is mainly microbiological challenge test. Physical
verification is an indirect way of confirming the effectiveness of the
sterilization, while microbiological challenge tests directly reflect
the effectiveness of sterilization, the two can not be replaced by each
other.
2.2.1 Physical confirmation
2.2.1.1 No-load heat distribution test
The
purpose of no-load heat distribution is to understand the operation of
the entire sterilization equipment, to confirm the temperature
uniformity in the sterilization chamber, to determine the temperature
difference between different locations in the sterilization chamber, and
to determine possible cold spots. No-load
thermal distribution tests usually use a sufficient number of
thermocouples or RTDs as temperature probes, which are numbered to hold
them in different positions in the chamber of the sterilizer. Depending
on the type of equipment and the sterilization risk assessment at
different locations, the location of the temperature probe should
include possible hot spots, cold spots, sterilizer temperature control
probes, temperature probes near the probe, other probes can be uniform
Distributed in the sterilization chamber, so that the temperature
detection is better representative. The temperature probe requires at least two temperature points to be calibrated before and after the test. After the temperature probe is placed, it can be sterilized according to the set sterilization program.
2.2.1.2 Load thermal distribution test
The
purpose of the loading thermal distribution test is to understand the
internal temperature distribution of the equipment under loading
conditions, including the locations of hot spots and cold spots, laying
the groundwork for subsequent evaluation and verification. Load heat distribution is generally carried out on the basis of no-load heat distribution. The number of the temperature probe and the placement of the general with
the no-load thermal distribution test, be sure to be placed in the
no-load thermal test to determine the cold junction temperature probe
installed. Temperature probe placed around the container to be sterilized, be careful not to be involved in the container to be sterilized.
The
loading heat distribution test needs to consider the maximum, minimum
and typical loading during the production. The products to be sterilized
should be used as far as possible. If similar, the appropriate risk
assessment should be carried out according to the thermodynamic
properties of the products. The
method of loading and sterilizing the product to be sterilized should
be set in accordance with the normal production. The chart should be
used to describe the loading of the product and evaluate whether the
probe is placed properly. If
different package specifications or concentration specifications exist
for the product to be sterilized, evaluate whether the samples used and
the method of loading will adequately reflect the actual loading of all
samples. Each loading load heat distribution test requires at least three times. Temperature probe also need to be calibrated before and after the test.
2 .2.1.3 Heat penetration test
The
heat penetration test is a test that examines the suitability of
sterilizers and sterilization procedures for sterilizing products. The purpose of the heat penetration test is to confirm that the inside of the product can also reach the predetermined sterilization temperature. In the case of pharmaceuticals, the sterilization procedure imparts a certain F 0 value to the product to ensure SAL ≤10 - 6 . In
the meantime, the sterilization procedure should not cause the drug to
partially degrade due to the overheating of the product, so that the
quality of the products in the same sterilized batch is not uniform.
The
number of heat probes used for the heat penetration test and the
location of the heat probes need to be determined based on the results
of the heat distribution test. In general, a sufficient number of temperature probes can be used . The
heat penetration temperature probe should be placed in the cold spot in
the liquid container, ie the most difficult place to sterilize the
entire package. If
there is data available or there is evidence that the probe is placed
outside the product package to reflect the thermal penetration of the
product, the risk can be fully controlled and the probe can be placed
outside the container. Place
the product with the temperature probe in place including cold and hot
spots as determined by the heat distribution test, other possible hot
spots, near the temperature probe of the sterilization cabinet, and at
the temperature recording probe.
The procedure and requirements for heat penetration tests are basically the same as those for thermal loading tests, and the thermal penetration test for each loading mode is also performed at least three times. Through
the heat penetration test can determine the set sterilization process,
the sterilization cabinet at various positions of the product to be
sterilized can reach the set temperature. Combined
with the detection of microbial contamination before sterilization, it
is possible to determine whether the product to be sterilized at various
locations within the sterilization cabinet can obtain the set F 0 value.
For the sample with the highest F o value,
the stability of the product at that location should be evaluated as it
is most heated, to further confirm that sterilization has no effect on
the stability of the product.
2.2.1.4 Analysis of heat distribution and heat penetration test data
In physical confirmation tests, key and important operating parameters should be identified and documented accordingly. The main parameters that usually need attention are:
- The range of temperature measured by each probe
- Measured temperature range between different probes
- The difference between the temperature measured by the probe and the set temperature
- The minimum and maximum time the probe measured above the set temperature
- Lower and upper limit of F 0
- The lowest F 0 value at the end of the sterilization phase
- The minimum and maximum pressure during the sterilization phase
- Relationship between saturated steam temperature and pressure
- The minimum and maximum temperature of the chamber during the sterilization phase
- Heat penetration temperature The maximum temperature difference between probes or the range of F 0
- heat distribution maximum temperature difference between the test temperature probe
- the longest equilibrium time
- The least normal number of probes
Qualified
standards should be combined with sterilization conditions, the
characteristics of sterilization equipment and product development. Under
normal circumstances, the coldest chamber sterilization, the hottest
and the average temperature difference between the temperature should
not exceed 2.5 ℃ . Temperature fluctuations within the holding time should be within ± 1.0 ℃ ,
if the temperature difference is too large, suggesting that the
performance of the sterilization cabinet does not meet the requirements,
need to find the cause and to improve and re-verify. In
addition for the heat-sensitive drugs, but also should control the
sterilization cabinet cooling and cooling time to ensure that the heat
input control within a reasonable range, will not affect the thermal
stability of the product.
2.2.2 biological confirmation
Microbiological challenge test of wet heat sterilization process means that a certain amount of known D value
of heat-resistant spores (biological indicator) sterilization under the
set conditions of wet heat sterilization to verify whether the set
sterilization process can indeed be achieved The standard sterilization
time required for the product and F 0 . This
validation can accurately reflect the sterilization process conditions
on the killing of microorganisms to prove that the sterilization process
to give the relevant products sterile guarantee level to meet the
requirements.
2.2.2.1 General guidelines for the selection of biological indicators
Under
normal circumstances, the biological indicator of the principle of
choice is: stable spores, non-pathogenic bacteria, easy to culture, a
long period of validity, preservation and easy to use, good safety. For
specific sterilization processes and specific products, it should also
be noted that the biological indicator used should be more
heat-resistant than the bacteria to be sterilized in the product to be
sterilized.
Wet
heat sterilization process commonly used biological indicators are the
following, Bacillus stearothermophilus, Bacillus subtilis, Bacillus
coagulans, Clostridium and so on. For
sterilization procedures that employ over kill methods, the biological
indicator system is primarily Bacillus stearothermophilus spores. Residual
Probability Method Because of its low heat input, biological indicators
used in validation can be less resistant to heat than spores of
Bacillus stearothermophilus.
2.2.2.2 biological indicator of the use and placement
The
actual verification process can be directly used commercially available
bio-indicator finished product or bio-indicator inoculated in the
product to be sterilized. When using commercially available products, as long as the supplier has the appropriate quality system certification, the D value of the biological indicator provided in the test can be accepted. With
the method of inoculating the biological indicator into the product to
be sterilized, since the biological indicator may have different heat
resistance in different media or environment, the influence of the
product on the heat resistance of the biological indicator should be
considered first. So
for a specific breed, if a biological indicator needs to be inoculated
into the product, the heat index of the biological indicator in the
product, ie, the D value , should be determined . If the biological indicator is incompatible with the product, replace the product with a solution similar to the product.
The
amount of biological indicator needs to be determined based on the heat
resistance of the biological indicator in the sample to be sterilized.
The dosage should meet the requirements of the challenging test. The amount of biological indicator can be calculated by the negative fraction method or the residual curve method, and the appropriate calculation method can be selected according to the actual situation (such as the heat resistance of the contaminated bacteria, the Dvalue of the biological indicator to be used, etc.). For the specific detection methods, see Annex 3 .
The
location of the biological indicator should be determined by combining
the product characteristics with the actual results of heat distribution
and heat penetration. The
container with the biological indicator should be placed close to the
container with the temperature probe and the biological indicator must
be placed at the cold point of the sterilization device. Other parts of the sterilizer should be loaded with products or the like to try to mimic the actual production conditions.
2.2.2.3 sterilization
Validation of biological indicators should be sterilized in accordance with the sterilization process set by the product.
2.2.2.4 inspection and training
Depending
on the growth characteristics of the biological indicator and the
method of packaging at the time of validation, appropriate methods of
examination and culture can be used. Put the indicator into the medium for culturing. It
should be noted that different biological indicators need different
culture conditions, biological indicators for the use of biological
conditions to determine the culture, should be placed negative and
positive control samples.
2.2.3.5 Evaluation of test results
According to the biological indicator of the D value and inoculum estimated product sterilization in the actual value of the SAL . When
validating a new sterilization process, a minimum of three consecutive
biological indicator validation tests are required for each
sterilization procedure per product specification for each product. If the test reproducibility, the results of all tests suggest SAL ≤ 10 -6 , the verification results suggest that the sterilization process to verify the qualified sterilization process. If
the result of each verification is inconsistent, it is necessary to
analyze the reason and take corresponding improvement measures to
re-verify the work.
3 preparation aseptic production process
3.1 aseptic production technology research
Sterile drugs should be the preferred end-use sterilization process. If
you can not tolerate the terminal sterilization process conditions,
should optimize the prescription process to improve its heat resistance. If you really can not tolerate the terminal sterilization process, you can use aseptic production process .Aseptic manufacturing processes usually include aseptic packaging process and sterilization filtration production process.
3.1.1 Aseptic dispensing process of production technology
Sterile dispensing process is the use of proven sterilization / sterilization
process after the treatment of bulk drugs or APIs and accessories,
using aseptic production method dispensing into a validated
sterilization process container , Sealed. Aseptic
packaging process technology research and production process control
focus on the level of sterility assurance process steps, including
materials (including APIs, accessories, packaging materials, etc.)
quality control, raw materials may be exposed to the environment may Re-pollution steps and so on.
Regarding
the quality control of materials, all kinds of materials involved in
the preparation of asepsis sub-assembly process must be used after
proper sterilization / sterilization process. Sterilization / sterilization of various materials should be validated and well-controlled. At
the same time the need for a variety of materials sterile, bacterial
endotoxin levels and other strict control, through the study to
determine the appropriate quality control standards.
Aseptically
packed the production process is the raw material medicine or raw
materials and accessories through the sub-packaging equipment packaging
materials within the packaging after the seal. The
dispensing step is a key production step that affects the quality of
the product and the level of sterility assurance. Process parameters
should be studied in combination with the characteristics of the
production equipment and the product, including the dispensing speed and
the dispensing time.
Aseptic
dispensing process can reach the set level of sterile assurance, and
the entire production process is closely related to the control should
be in accordance with GMP requirements and product specific production process conditions and control of the production environment. In
the aseptic production process verification, the worst conditions
should be used to verify the actual production process, the control of
the production process and process parameters can not exceed the
worst-case control conditions have been verified.
3.1.2 filter sterilization production process research
Sterile filter sterilization process is through the sterile filter, the liquid in the microorganisms to get sterile filtrate. The
use of filter sterilization process, the same need to influence the
level of sterility assurance process steps and process parameters for a
detailed study, including material quality control, selection
of sterilization filter and sterilization filtration process
parameters, sterilization Filter the production process control.
For
the preparation of the filter-sterilized production process, attention
should be paid to the examination of the types and quantities of the
microorganisms in the raw materials and excipients (including water for
injection) used in the preparation of the medicinal solution to grasp
the overall characteristics of the potential contaminating
microorganisms and to determine The corresponding quality control standards. The
inner packaging material used in the preparation of the
filter-sterilized production process must be disposed of with a
suitable, proven sterilization process.
Sterilizing filtration Sterilizing filters used in the production process are usually sterilizing grade filters with a nominal pore size of 0.2 μm or less. Filtration
efficiency of sterilization filter is an important parameter to
evaluate the sterilization filtration process, the filtration efficiency
of sterilization filter needs to be verified. In general, the factors that affect the sterilizing and filtration efficiency of the sterilizing filter include: ① the nature of the medicinal solution, such as the viscosity of the medicinal solution , the surface tension, the pH value and the osmotic pressure; ② the technological parameters of the filtering step such as filtration pressure, Flow rate, time, temperature, etc .; ③ sterilization
filter-related parameters, such as sterilization filter and liquid
compatibility, the total amount of filter sterilization and the use of
the cycle and so on. The filtration efficiency of sterilization filters can vary significantly depending on the product and the operating conditions. The
selection of sterilization filters and the study of process parameters
can be combined with the above factors that affect the filtration
efficiency of the sterilization filter . In the actual production process, before and after the filter sterilization filter integrity test needs to be carried out. Since
microorganisms increase with the number of microbes in the solution to
be filtered by the filter probability, the need for sterile filtration
process the microbial load in the case where the solution to be filtered and the controlled study, Typically, prior to the final sterilization filter, frit Liquid microbial load should not exceed 10cfu / 100ml . Should
be determined through the study of aseptic production of various
aspects of the operation of the time control, such as the liquid preparation to be filtered after the storage time, liquid
filtration operation time, filtered to fill the time before filling,
potting operation time, off After the bacteria within the packaging
materials and seals allowed to place the time. The determination of the operation time of each production link shall provide the corresponding test data.
3.2 aseptic production process validation
Validation
of the aseptic manufacturing process consists mainly of media simulated
filling trials and should attempt to simulate conventional aseptic
manufacturing processes to the extent possible, including all the key
operations that have an effect on the aseptic results and the various
interventions that may occur in production and the worst condition. The
new sterile production process of the production line in the formal
commissioning of three batches of sterile media must be simulated before
filling experiment. In
the production of equipment, facilities, personnel structure and
process methods have major changes in the medium should be simulated
filling test. The actual production should be carried out at least once every six months medium filling simulation test.
For
sterilization sterilization aseptic production process validation, but
also includes sterilization of filtration system validation, such as
filter retention of microorganisms, filter and filter to be filtered
liquid compatibility verification, filter integrity verification.
3.2.1 medium simulated filling test
3.2.1.1 Culture medium
Media Mock Filling tests require the selection of a suitable medium and control of the quality of the medium.
The
medium should be chosen based on the dosage form of the product, the
medium's selectivity, clarity, concentration and suitability for
sterilization. General selection of tryptone soy broth ( TSB ), according to 30g plus 1L filtered purified water ratio, formulated in sufficient quantity. In some special cases, anaerobic growth media such as thioglycollate media ( FTM ) can also be used .
The quality control of the culture medium mainly includes the growth performance and sterility of the culture medium.
Microbial growth performance of the medium: After the medium is prepared and sterilized according to the standard
operating procedures, the growth performance test of the medium may be
conducted according to the appendix of the Chinese Pharmacopoeia to
confirm that the growth of the inoculated microorganism should be
obvious in the prepared medium.
Aseptic medium: The Chinese Pharmacopoeia appendix can be sterilized culture medium, the results should be consistent with the provisions.
In
the medium simulation filling test, a positive control test should be
carried out, that is, a low concentration strain should be inoculated
into a control container for positive test and incubated under the same
conditions as the medium simulated filling test. In
addition to the positive bacteria specified in the appendix of the
Chinese Pharmacopoeia, it is recommended to use microorganisms commonly
found in the production environment , such as Bacillus subtilis, Candida albicans, or those that have been detected in the same production environment. Inoculum is typically less than 10 2 per container , with 2 inoculations per strain , usually with confirmed bacterial growth, validated by filling the medium with this medium.
If
the test requires the use of simulated powder for packaging, also need
to simulate the dispensing powder selection and quality control. The choice of powder for analog dispensing usually follow the following principles: ① can be sterilized in the state of dry powder, sterility after sterilization to meet Pharmacopoeia standards; ② liquidity better, can be sub-packaging machines; ③ soluble In liquid medium; ④ no inhibitory effect at the concentration applied in the simulation test. Commonly used analog packaging materials are lactose, mannitol, PEG6000 , PEG8000, etc., can also be used as a simulated dry powder packing media with sterile powder.
3.2.1.2 Simulation of aseptic production process operation
The
process of cleaning, sterilizing the inner packaging material used in
the simulated filling test of the medium, and cleaning, sterilizing and
disinfecting the equipment of the dispensing equipment in contact with
the product should be the same as the actual production operation The
standard operating procedures. Sampling
plans should be drawn during the simulated filling test of the medium.
Aseptic sampling should be carried out randomly after a certain number
of inner packaging materials are used. At the same time, the surface of
all equipment that is in contact with the product should be sterile. In
some special cases, such as rubber stopper with antibacterial
properties, you need to consider replacing other equivalent but
non-bacteriostatic rubber stopper.
Care
should be taken that there is a sufficient amount of media in full
contact with the inner surface of the container. When filling the media,
the volume of each container should normally be between 1 3/2 and not more than 85% of the container . It
should be noted that for the freeze-dried powder injection validation
test, only the process of entering and exiting the lyophilizer can be
simulated after the media has been filled with the half-pressure plug
without having to model the freeze-drying process to ensure that once
the bacteria, To maintain good viability. At the same time, should also simulate some possible pollution caused by the steps, such as vacuum, nitrogen and other steps.
Media-simulated filling trials should
simulate conventional aseptic manufacturing processes to the extent
possible and should include all the key operations that have an impact
on the aseptic results, including the various interventions and
worst-case conditions that may occur during production, the various
interventions and the worst Conditions need to reflect the concept of
risk control. The most common types of interventions and worst-case conditions that may occur include: (i ) the number of personnel and their activities, shifts, rests, alterations (when required), ( ii) equipment commissioning, normal parking, abnormal parking, accidents (3) using the longest time allowed after sterilization equipment or workshop production; ( 4) simulation of the longest batch production time required; (5)the
slowest filling speed and the largest packaging container (ie the
longest exposure Time); with the fastest filling speed and the smallest
packaging container (that is, easy to follow the production of more interventions) . In
summary, in the pilot program, the overall study design and run-time
should model the various interventions and worst-case operating
conditions that may arise, covering all the operations involved in the
actual production process.
The
amount of medium simulating filling should be sufficient to ensure the
validity of the assessment. The smaller batches of product, the number
of simulated bottoms for the medium, should be at least equal to the
batch size of the product.
3.2.1.3 Evaluation of test results
Media Filling Tests All cultures are filled and sterilized. The goal of a medium-simulated filling test is zero contamination and should meet the following requirements:
Filling quantity
|
The amount of pollution allowed
|
Less than 5000 when
|
May not be detected contaminated goods
|
5000 to 10000 hours
|
There . 1 branched pollution, required investigation, repeat the test can be considered;
There are 2 pollution, to be investigated, to re-verify
|
Chaoguo 10000 when branch
|
There are 1 Zhi pollution, need investigation;
There are 2 pollution, to be investigated, to re-verify
|
Once
the pollution is found, it is necessary to conduct a deviation survey,
including the identification of the contaminated bacteria, the
assessment of the pollution situation, whether the experiment can be
repeated or not.
3.2.2 sterilization filtration system validation
Verification
of sterilization filtration system generally includes: microbial
entrapment studies, precipitation studies, chemical compatibility
studies and liquid adsorption studies.
3.2.2.1 Microbial entrapment studies
Microbial retention filter validation purposes: Microbial
sterilization filter retention test is through the simulation of the
actual filtration process, the filter contains a certain amount of
biological indicator bacteria solution to confirm the microbial retention of bacteria removal filter capacity.
Microbial retention filter validation design:
( 1 ) challenge the choice of microorganisms
Defective Pseudomonas is commonly used as a challenge test. In some cases, Pseudomonas aeruginosa may not be representative of the worst conditions, you need to consider the use of other bacteria. If
other bacteria are used, ensure that the bacteria is small enough to
challenge the retention of the bacteria-removal filter and mimic the
smallest microorganisms found in the product. Microbiological
load should be identified and quantified as much as possible to
understand the morphological characteristics of the isolated
microorganisms and provide a basis for the selection of challenging
microorganisms.
The size of the challenging microorganism can be confirmed by its ability to pass through a 0.45 micron filter. Typically, Pseudomonas aeruginosa grown under standard culture conditions can pass through a 0.45- micron filter at a high challenge concentration (eg ≧ 10 7 ) .
( 2 ) Microbial retention test conditions
Simulated
in the laboratory production process conditions, the quantitative
Pseudomonas imperfecta added to the feed solution, filtered. According
to the actual production conditions, consider determining the microbial
entrapment test filtration time and temperature, pressure, flow rate
and so on. It
is advisable to conduct a thorough assessment of the actual filtration
process, including the nature of the solvent (eg aqueous, acid, alkali,
organic), filtration time, process pressure, process flow rate, process
temperature and filter design specifications for rational design of
microorganisms Retention test conditions.
Filtration time and pressure differential affect the results of the bacterial retention test. Microbial
entrapment tests at full production time can assess those time-related
factors such as filter compatibility, maintenance of integrity, and
time-dependent penetration.
The pressure drop during the Microbial Retention Test should meet or exceed the maximum pressure differential and / or maximum flow rate (within the filter manufacturer's design specifications) for the actual process . It may not be possible to simulate the pressure differential and flow rate simultaneously during verification. The
user of the filter should be able to confirm which parameter is more
relevant to a particular process when designing the test conditions to
provide a basis for the determination of microbial retention test
conditions.
Microbial entrapment validation studies should include multiple batches of filters (usually three batches). Of
the three batches of filters used in microbial entrapment validation
studies, at least one of the batches is the value at which the pre-study
or pre-use physical integrity test was passed but was close (eg, within 10 %) Manufacturer's specification of acceptable limits.
( 3 )
Physical integrity testing of filter membranes used in microbial
retention validation studies should be included in the experimental
report. Physical
integrity testing should be tested using water, products or other
wetting fluids already in the specification and completed prior to the
microbial challenge.
If
the test microorganism is detected downstream of any filter after the
microbial entrapment validation study, then it needs to be investigated. If
the survey confirms that the test microorganisms are able to penetrate
the filter that meets the integrity test, then the applicability of such
a filter under these operating conditions should be reconsidered.
It is important to note that repeated use of filters is generally not recommended. If
you need to re-use sterile filter, you need to explain the reasons,
reuse of the relevant parameters (such as the amount of filtration,
etc.) also need to go through rigorous validation to determine the
appropriate range.
3.2.2.2 Precipitates and emissions studies
Precipitate
refers to any chemical component that separates from a material under
artificial or challenging conditions such as solvent, temperature, or
time. Discharge
means the substance that enters the product or process fluid from the
contact surface under normal conditions of storage or use. Potential
sources of precipitates or release include, but are not limited to: the
membrane module (eg: forming agent, a surfactant, an antioxidant, a
residual solvent, a stent layer) and the plastic components (such as:
cover, housing, holder, O -type ring). Factors
that affect emissions may include the chemistry of the filtrate, the
method of sterilization, contact time, temperature, and the amount of
filtration versus area. Filtration of organic solutions may produce emissions that are higher than aqueous solutions.
Precipitant data are available from filter manufacturers and can also be tested by filter users. Considering
the different sources of the precipitates and the many factors that
affect the precipitates, it is advisable for the filter user to use the
actual product whenever possible and to use the same type of filter as
the actual production. In
some cases it may be necessary to use alternative solutions for
testing. For example, the product may interfere with the analytical
method or the product has antibacterial properties. In this case, the replacement solution must be as consistent as possible with the product to be filtered. In addition, you can choose to use several solutions to cover the actual filtration solution pH , ionic strength or organic content and other characteristics. If
alternative solutions or combinations of several solutions are used, a
reasonable basis for solution selection must be provided.
Once
the extraction solution (product, replacement fluid, or a combination
of several solutions) used in the precipitation test is identified, the
worst-case conditions of the actual production conditions should be
simulated during the design of the test, taking into account, for
example, temperature, time, pH and pre- Processing (such as: washing, sterilization) processes and other key variables. Precipitation
tests should be carried out using the contact time and temperature of
the filtration unit at the worst production conditions, using an
autoclaved or sterilized filter. You can use static soaking or circulating flow method. When
using the static immersion method, the filter is soaked in the
precipitating solution at a given temperature for a predetermined period
of time. The
use of circulating flow method, the extraction solution in a
predetermined period of time repeatedly through the filter cycle. The extract is collected and tested to determine the filter precipitates therein.
After obtaining the filter extract, the type and amount of material from the filter can be determined by analysis. In
addition to determining the type and amount of precipitates on the
filter, the safety can also be assessed, if necessary, using approved
bioreactivity tests.
3.2.2.3 Compatibility studies
The
filter compatibility studies are used to assess the chemical
compatibility of the filter unit with the feed liquid to avoid possible
filter damage or deformation and to prevent contamination of the feed
liquid with emissions or particulate matter. The
chemical compatibility test shall cover the entire installation. The
design of the test shall take into account the properties of the
feedstock, the filtration temperature and the contact time. Due
to the many chemical interactions that may exist between the filtration
device and the filter liquor or solvent, a representative chemical
compatibility list provided by the filter manufacturer is often used as a
reference only for filter users who need to make more Comprehensive
test. Common
chemical compatibility tests include: visual inspection before and after
contact with the feed liquid, flow rate changes during filtration,
membrane weight changes, changes in bubble point before and after
filtration, and the like.
3.2.2.4 Adsorption studies
Adsorption
is the process by which certain components of the filtered feedstock
adhere to the filter membrane, which may affect the composition and
concentration of the feedstock. Adsorbable materials in the filter include filters, hardware, and supporting materials. Adsorption
test conditions can be determined according to the actual production
conditions, the flow rate, filtration time, feed concentration,
preservative concentration, temperature and pH and other factors may affect the adsorption effect. Adsorption test used in the test method can be used to determine the product quality standards related to detection methods.
4 API sterile production process
Sterile bulk drug refers to the provisions of the statutory pharmaceutical standards sterile test items of bulk drugs. Common
chemical raw materials production processes include chemical synthesis,
microbial fermentation process, and the use of microbial fermentation
products as a starting material for the semi-synthetic process; and
aseptic processing of raw materials for drugs specifically made of
aseptic processing of raw materials Of the relevant process, aseptic
process before the production process is outside the scope of this
chapter. However,
for the verification of aseptic processing of aseptic excipients (eg
arginine hydrochloride, sodium bicarbonate, etc.) for the production of
sterile preparations, reference may also be made to the relevant
requirements of these guidelines.
Compared
with the sterile preparation process, the production process of sterile
drug substance is generally more complex, the type of equipment is
varied, and the different processes have different characteristics. Sterilization
and aseptic transfer of materials, packaging materials, equipment
(including valves, pipes and other related components), docking and
assembly are much more complicated than aseptic preparations in the
process. A common method for converting APIs from non-sterile to sterile is through sterile filtration. The
process is greatly affected by the nature of the feed liquid, depending
on the nature of the feed liquid to choose the appropriate filter and
filter material. In
addition, the production equipment for APIs is usually large in volume
and complicated in internal structure. When choosing a location for
placement , feeding, sampling and recycling, it is necessary to consider
how to ensure that the flow of air in the clean area meets the
requirements and how to match the efficiency of the filter Location and
distribution of equipment between the body and so on.
Although
there are many differences in the manufacturing process and quality
control between sterile and sterile APIs, the basic requirements for
sterility assurance and the basic principles of production management
and validation are similar. Therefore,
in the production equipment, plant facilities, cleanliness and
monitoring, sterilization processes and methods and quality control
requirements, the requirements of sterile APIs and sterile formulations
can be cross-referenced.
4.1 sterile raw material production process characteristics
Sterile APIs can be obtained by means of final sterilization or non-final sterilization. For
sterile APIs with final sterilization, the level of microbial
contamination, bacterial endotoxins, and insoluble particulates must be
carefully controlled. Since most APIs have poor heat resistance, they are usually produced by non-terminal sterilization.
Sterilization
of sterile raw materials and sterilization process often combined
together as a unit of production processes to complete the operation. Currently
the most commonly used method of production is sterile filtration; that
is, the preparation of non-sterile intermediates or raw materials into a
solution, and then through a 0.22μm pore size filter to achieve the purpose of removing bacteria. Aseptic
raw materials commonly used processes include solvent crystallization
and freeze-drying of two kinds of pre-spray spray drying process also
has a sterile raw material medicine, but mostly because of its
production process can not meet the verification requirements of aseptic
process and gradually abandoned or carried out the process change.
The
specific equipment and operations involved in the solvent
crystallization and freeze-drying processes vary, but all utilize
sterile filtration to allow the feedstock to change from a non-sterile
to a sterile state and thereafter dry, comminute, mix, and Dispense
process always maintain a sterile state.
4.1.1 solvent crystallization process
Typical
solvent crystallization process includes the dissolution of non-sterile
drug substance, sterilization filtration, crystallization, solid-liquid
separation (such as common filtration, centrifugation and other
methods), washing, drying, crushing, mixing, packaging and other
processes. Dissolution
should focus on the microbial load of the material, the quality of the
solvent, the level of microbial contamination of the equipment, and the
level of microbial contamination of the source of feed fluid (such as
air or nitrogen) used. Sterilization filter should pay attention to the filter
itself sterile, filter and feed compatibility, the filter itself and
the integrity of the assembly, the filter cleaning and sterilization
cycle, the filter sterilization efficiency, sterilization Pre-filter
liquid microbial contamination levels. Crystallization
should pay attention to equipment aseptic, sealing and sealing device
reliability, equipment cleaning and sterilization cycle, the integrity
of the ventilator and sterility; seed crystal itself should be
consistent with sterile drugs Requirements, and sterility assurances
should be validated during seed addition. Filtration
or centrifugation should pay attention to equipment aseptic, sealing
performance and sealing device reliability, cleaning and sterilization
cycle, the integrity of the ventilator and sterility. Washing should pay attention to the washing process of sterility. Drying
should pay attention to the sterility of drying equipment, sealing
performance and reliability of the sealing device, cleaning and
sterilization cycle, the integrity and sterility of the respirator, and
the anti-suction setting of the vacuum system (if using a vacuum,
Pipeline installed sterile level filter). Shredding
should pay attention to equipment aseptic, sealing performance and
reliability of the sealing device; grinding gas (such as the use of jet
mill) sterile assurance, feeding methods, such as the level of sterile
assurance. Mixing
should pay attention to equipment sterility, sealing performance and
sealing device reliability, cleaning and sterilization cycles. Packing
should pay attention to the quality of the dispensing equipment itself
or the level of cleanliness of its products meet the A -level
standards, concerned about the aseptic packaging materials, packaging
materials into the way, the tightness of the inner packaging containers
and Sampling steps of the sterile guarantee.
4.1.2 freeze-drying process
Typical
procedures for freeze-drying aseptic APIs include dissolving,
sterilizing, sterilizing, freeze-drying, comminuting, mixing and
dispensing of APIs. In
addition to the freeze-drying process, the focus of other process steps
can refer to the relevant requirements of the solvent crystallization
process. The main issues to be concerned in the freeze-drying process include the sterility of the freeze-drying machine
and its ancillary equipment, the sealing performance and the
reliability of the sealing device, the cleaning and sterilization cycle,
the cleaning and sterilizability of the equipment, the vacuum system
Guarantee and pressure balance after drying, aseptic guarantee of gas
supplementing process (should add aseptic gas or sterilizing respiration
filter on the freeze dryer), and the sterility assurance when the
material enters and exits the equipment .
4.2 sterile raw material process validation
Sterilization
of raw materials used by the terminal sterilization process validation
can refer to the preparation of terminal sterilization process
validation requirements. Non-terminal
sterilization of sterile raw material drug process validation include
media simulation filling verification and filtration sterilization
system validation. One of the filter sterilization system validation can refer to the relevant requirements of sterile formulations, and focus on access
to the crystallization tank of all materials (such as APIs, solvents,
acid and alkali, gas, etc.) should be sterile filtered and verified.
Conventional production of small quantities of sterile bulk drugs, should maximize the simulation of large batch production. For
a large volume of conventional sterile APIs, given the feasibility of
simulating a large production lot and the feasibility of actual media
cultivation, the simulated filling lot size may be smaller than the
larger production lot size but the simulation media should have access to all products Contact the inner surface of the device. And can fully simulate actual production may encounter other various worst conditions.
When
selecting the worst case, consideration should be given to the number
of occupants (including maintenance personnel), the exposure time for
the materials and equipment in the aseptic zone, the interval between
the start of filling after the equipment is sterilized, and the
microbial inhibitors (e.g, temperature, Nitrogen protection, antibiotics)
adjustment and elimination. It
should be confirmed whether the simulated medium can reach the surfaces
that all the sterile products in the actual production process may
reach, whether the time interval is comparable (for example, the
dissolution filtration time should not be shorter than the time used in
the actual production process), time To simulate the worst conditions to
extend, if you shorten the time to simulate, you need to demonstrate / demonstrate whether the conditions for shortening the time can be equivalent to the worst conditions of the production process.
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