MANUFACTURE OF STERILE MEDICINAL PRODUCTS

1
ANNEX 1

Principle
The manufacture of sterile products is subject to special requirements in order to minimise risks
of microbiological contamination, and of particulate and pyrogen contamination. Much depends
on the skill, training and attitudes of the personnel involved. Quality Assurance is particularly
important, and this type of manufacture must strictly follow carefully established and validated
methods of preparation and procedure. Sole reliance for sterility or other quality aspects must
not be placed on any terminal process or finished product test.
Note:
The present guidance does not lay down detailed methods for determining the microbiological
and particulate cleanliness of air, surfaces etc. Reference is made to other compendia such as
the CEN/ISO Standards.
General
1. The manufacture of sterile products should be carried out in clean areas entry to which should
be through airlocks for personnel and/or for equipment and materials. Clean areas should be
maintained to an appropriate cleanliness standard and supplied with air which has passed
through filters of an appropriate efficiency.
2. The various operations of component preparation, product preparation and filling should be
carried out in separate areas within the clean area.
Manufacturing operations are divided into two categories; firstly those where the product is
terminally sterilised, and secondly those which are conducted aseptically at some or all stages.
3. Clean areas for the manufacture of sterile products are classified according to the required
characteristics of the environment. Each manufacturing operation requires an appropriate
environmental cleanliness level in the operational state in order to minimise the risks of
particulate or microbial contamination of the product or materials being handled.
In order to meet “in operation” conditions these areas should be designed to reach certain
specified air-cleanliness levels in the “at rest” occupancy state. The “at-rest” state is the
condition where the installation is installed and operating, complete with production equipment
but with no operating personnel present. The “in operation” state is the condition where the
installation is functioning in the defined operating mode with the specified number of personnel
working.
______________________________ Annex 1 Manufacture of sterile medicinal products n
For the manufacture of sterile medicinal products there are normally 4 grades of clean areas.
Grade A: The local zone for high risk operations, e.g. filling zone, stopper bowls, open
ampoules and vials, making aseptic connections. Normally such conditions are provided by a
laminar air flow work station. Laminar air flow systems should provide a homogeneous air
speed of 0.45 m/s ± 20 % (guidance value) at the working position.
Grade B: For aseptic preparation and filling, this is the background environment for grade A
zone.
Grade C and D: Clean areas for carrying out less critical stages in the manufacture of sterile
products.
The airborne particulate classification for these grades is given in the following table.
at rest (b) in operation
Grade maximum permitted number of particles/m3 equal to or above
0.5 μm 5 μm 0.5 μm 5 μm
A 3 500 0 3 500 0
B (a) 3 500 0 350 000 2 000
C (a) 350 000 2 000 3 500 000 20000
D (a) 3 500 000 20 000 not defined (c) not defined (c)
Notes
(a) In order to reach the B, C and D air grades, the number of air changes should be
related to the size of the room and the equipment and personnel present in the room.
The air system should be provided with appropriate filters such as HEPA for grades A,
B and C.
(b) The guidance given for the maximum permitted number of particles in the "at rest"
condition corresponds approximately to the US Federal Standard 209 E and the ISO
classifications as follows: grades A and B correspond with class 100, M 3.5, ISO 5;
grade C with class 10.000, M 5.5, ISO 7 and grade D with class 100.000, M 6.5, ISO 8.
(c) The requirement and limit for this area will depend on the nature of the operations
carried out.
Examples of operations to be carried out in the various grades are given in the table below. (see
also par. 11 and 12)
Grade Examples of operations for terminally sterilised products. (see par. 11)
A Filling of products, when unusually at risk.
C Preparation of solutions, when unusually at risk. Filling of products
D Preparation of solutions and components for subsequent filling.
______________________________ Annex 1 Manufacture of sterile medicinal products n
Grade Examples of operations for aseptic preparations. (see par. 12)
A Aseptic preparation and filling.
C Preparation of solutions to be filtered.
D Handling of components after washing.
The particulate conditions given in the table for the "at rest" state should be achieved in the
unmanned state after a short "clean up" period of 15-20 minutes (guidance value), after
completion of operations. The particulate conditions for grade A in operation given in the table
should be maintained in the zone immediately surrounding the product whenever the product or
open container is exposed to the environment. It is accepted that it may not always be possible
to demonstrate conformity with particulate standards at the point of fill when filling is in progress,
due to the generation of particles or droplets from the product itself.
4. The areas should be monitored during operation, in order to control the particulate cleanliness
of the various grades.
5. Where aseptic operations are performed monitoring should be frequent using methods such as
settle plates, volumetric air and surface sampling (e.g. swabs and contact plates). Sampling
methods used in operation should not interfere with zone protection. Results from monitoring
should be considered when reviewing batch documentation for finished product release.
Surfaces and personnel should be monitored after critical operations.
Additional microbiological monitoring is also required outside production operations, e.g. after
validation of systems, cleaning and sanitisation.
Recommended limits for microbiological monitoring of clean areas during operation.
Recommended limits for microbial contamination (a)
Grade air sample
cfu/m3
settle plates
(diam. 9 0 mm),
cfu/4 hours (b)
contact plates
(diam. 55 mm),
cfu/plate
glove print
5 fingers
cfu/glove
A < 1 < 1 < 1 < 1
B 10 5 5 5
C 100 50 25 –
D 200 100 50 –
Notes
(a) These are average values.
(b) Individual settle plates may be exposed for less than 4 hours.
______________________________ Annex 1 Manufacture of sterile medicinal products n
6. Appropriate alert and action limits should be set for the results of particulate and microbiological
monitoring. If these limits are exceeded operating procedures should prescribe corrective
action.
Isolator technology
7. The utilisation of isolator technology to minimise human interventions in processing areas may
result in a significant decrease in the risk of microbiological contamination of aseptically
manufactured products from the environment. There are many possible designs of isolators and
transfer devices. The isolator and the background environment should be designed so that the
required air quality for the respective zones can be realised. Isolators are constructed of various
materials more or less prone to puncture and leakage. Transfer devices may vary from a single
door to double door designs to fully sealed systems incorporating sterilisation mechanisms.
The transfer of materials into and out of the unit is one of the greatest potential sources of
contamination. In general the area inside the isolator is the local zone for high risk
manipulations, although it is recognised that laminar air flow may not exist in the working zone
of all such devices. The air classification required for the background environment depends on
the design of the isolator and its application. It should be controlled and for aseptic processing it
should be at least grade D.
8. Isolators should be introduced only after appropriate validation. Validation should take into
account all critical factors of isolator technology, for example the quality of the air inside and
outside (background) the isolator, sanitisation of the isolator, the transfer process and isolator
integrity.
9. Monitoring should be carried out routinely and should include frequent leak testing of the
isolator and glove/sleeve system.
Blow/fill/seal technology
10. Blow/fill/seal units are purpose built machines in which, in one continuous operation, containers
are formed from a thermoplastic granulate, filled and then sealed, all by the one automatic
machine. Blow/fill/seal equipment used for aseptic production which is fitted with an effective
grade A air shower may be installed in at least a grade C environment, provided that grade A/B
clothing is used. The environment should comply with the viable and non viable limits at rest
and the viable limit only when in operation. Blow/fill/seal equipment used for the production of
products which are terminally sterilised should be installed in at least a grade D environment.
Because of this special technology particular attention should be paid to, at least the following:
equipment design and qualification, validation and reproducibility of cleaning-in-place and
sterilisation-in-place, background cleanroom environment in which the equipment is located,
operator training and clothing, and interventions in the critical zone of the equipment including
any aseptic assembly prior to the commencement of filling.
Terminally sterilised products
11. Preparation of components and most products should be done in at least a grade D
environment in order to give low risk of microbial and particulate contamination, suitable for
filtration and sterilisation. Where the product is at a high or unusual risk of microbial
contamination, (for example, because the product actively supports microbial growth or must be
held for a long period before sterilisation or is necessarily processed not mainly in closed
vessels), then preparation should be carried out in a grade C environment.
Filling of products for terminal sterilisation should be carried out in at least a grade C
environment.
______________________________ Annex 1 Manufacture of sterile medicinal products n
Where the product is at unusual risk of contamination from the environment, for example
because the filling operation is slow or the containers are wide-necked or are necessarily
exposed for more than a few seconds before sealing, the filling should be done in a grade A
zone with at least a grade C background. Preparation and filling of ointments, creams,
suspensions and emulsions should generally be carried out in a grade C environment before
terminal sterilisation.
Aseptic preparation
12. Components after washing should be handled in at least a grade D environment. Handling of
sterile starting materials and components, unless subjected to sterilisation or filtration through a
micro-organism-retaining filter later in the process, should be done in a grade A environment
with grade B background.
Preparation of solutions which are to be sterile filtered during the process should be done in a
grade C environment; if not filtered, the preparation of materials and products should be done in
a grade A environment with a grade B background.
Handling and filling of aseptically prepared products should be done in a grade A environment
with a grade B background.
Prior to the completion of stoppering, transfer of partially closed containers, as used in freeze
drying should be done either in a grade A environment with grade B background or in sealed
transfer trays in a grade B environment.
Preparation and filling of sterile ointments, creams, suspensions and emulsions should be done
in a grade A environment, with a grade B background, when the product is exposed and is not
subsequently filtered.
Personnel
13. Only the minimum number of personnel required should be present in clean areas; this is
particularly important during aseptic processing. Inspections and controls should be conducted
outside the clean areas as far as possible.
14. All personnel (including those concerned with cleaning and maintenance) employed in such
areas should receive regular training in disciplines relevant to the correct manufacture of sterile
products. This training should include reference to hygiene and to the basic elements of
microbiology. When outside staff who have not received such training (e.g. building or
maintenance contractors) need to be brought in, particular care should be taken over their
instruction and supervision.
15. Staff who have been engaged in the processing of animal tissue materials or of cultures of
micro-organisms other than those used in the current manufacturing process should not enter
sterile-product areas unless rigorous and clearly defined entry procedures have been followed.
16. High standards of personal hygiene and cleanliness are essential. Personnel involved in the
manufacture of sterile preparations should be instructed to report any condition which may
cause the shedding of abnormal numbers or types of contaminants; periodic health checks for
such conditions are desirable. Actions to be taken about personnel who could be introducing
undue microbiological hazard should be decided by a designated competent person.
17. Changing and washing should follow a written procedure designed to minimise contamination of
clean area clothing or carry-through of contaminants to the clean areas.
18. Wristwatches, make-up and jewellery should not be worn in clean areas.
19. The clothing and its quality should be appropriate for the process and the grade of the working
area. It should be worn in such a way as to protect the product from contamination.
The description of clothing required for each grade is given below:
______________________________ Annex 1 Manufacture of sterile medicinal products n
Grade D: Hair and, where relevant, beard should be covered. A general protective suit and
appropriate shoes or overshoes should be worn. Appropriate measures should be taken to
avoid any contamination coming from outside the clean area.
Grade C: Hair and where relevant beard and moustache should be covered. A single or twopiece
trouser suit, gathered at the wrists and with high neck and appropriate shoes or
overshoes should be worn. They should shed virtually no fibres or particulate matter.
Grade A/B: Headgear should totally enclose hair and, where relevant, beard and moustache; it
should be tucked into the neck of the suit; a face mask should be worn to prevent the shedding
of droplets. Appropriate sterilised, non-powdered rubber or plastic gloves and sterilised or
disinfected footwear should be worn. Trouser-legs should be tucked inside the footwear and
garment sleeves into the gloves. The protective clothing should shed virtually no fibres or
particulate matter and retain particles shed by the body.
20. Outdoor clothing should not be brought into changing rooms leading to grade B and C rooms.
For every worker in a grade A/B area, clean sterile (sterilised or adequately sanitised) protective
garments should be provided at each work session, or at least once a day if monitoring results
justify this. Gloves should be regularly disinfected during operations. Masks and gloves should
be changed at least at every working session.
21. Clean area clothing should be cleaned and handled in such a way that it does not gather
additional contaminants which can later be shed. These operations should follow written
procedures. Separate laundry facilities for such clothing are desirable. Inappropriate treatment
of clothing will damage fibres and may increase the risk of shedding of particles.
Premises
22. In clean areas, all exposed surfaces should be smooth, impervious and unbroken in order to
minimise the shedding or accumulation of particles or micro-organisms and to permit the
repeated application of cleaning agents, and disinfectants where used.
23. To reduce accumulation of dust and to facilitate cleaning there should be no uncleanable
recesses and a minimum of projecting ledges, shelves, cupboards and equipment. Doors
should be designed to avoid those uncleanable recesses; sliding doors may be undesirable for
this reason.
24. False ceilings should be sealed to prevent contamination from the space above them.
25. Pipes and ducts and other utilities should be installed so that they do not create recesses,
unsealed openings and surfaces which are difficult to clean.
26. Sinks and drains should be prohibited in grade A/B areas used for aseptic manufacture. In other
areas air breaks should be fitted between the machine or sink and the drains. Floor drains in
lower grade clean rooms should be fitted with traps or water seals to prevent back-flow.
27. Changing rooms should be designed as airlocks and used to provide physical separation of the
different stages of changing and so minimise microbial and particulate contamination of
protective clothing. They should be flushed effectively with filtered air. The final stage of the
changing room should, in the at-rest state, be the same grade as the area into which it leads.
The use of separate changing rooms for entering and leaving clean areas is sometimes
desirable. In general hand washing facilities should be provided only in the first stage of the
changing rooms.
28. Both airlock doors should not be opened simultaneously. An interlocking system or a visual
and/or audible warning system should be operated to prevent the opening of more than one
door at a time.
29. A filtered air supply should maintain a positive pressure and an air flow relative to surrounding
areas of a lower grade under all operational conditions and should flush the area effectively.
Adjacent rooms of different grades should have a pressure differential of 10 - 15 pascals
(guidance values). Particular attention should be paid to the protection of the zone of greatest
risk, that is, the immediate environment to which a product and cleaned components which
contact the product are exposed. The various recommendations regarding air supplies and
______________________________ Annex 1 Manufacture of sterile medicinal products n
pressure differentials may need to be modified where it becomes necessary to contain some
materials, e.g. pathogenic, highly toxic, radioactive or live viral or bacterial materials or
products. Decontamination of facilities and treatment of air leaving a clean area may be
necessary for some operations.
30. It should be demonstrated that air-flow patterns do not present a contamination risk, e.g. care
should be taken to ensure that air flows do not distribute particles from a particle-generating
person, operation or machine to a zone of higher product risk.
31. A warning system should be provided to indicate failure in the air supply. Indicators of pressure
differences should be fitted between areas where these differences are important. These
pressure differences should be recorded regularly or otherwise documented.
Equipment
32. A conveyor belt should not pass through a partition between a grade A or B area and a
processing area of lower air cleanliness, unless the belt itself is continually sterilised (e.g. in a
sterilising tunnel).
33. As far as practicable equipment, fittings and services should be designed and installed so that
operations, maintenance and repairs can be carried out outside the clean area. If sterilisation is
required, it should be carried out, wherever possible, after complete reassembly.
34. When equipment maintenance has been carried out within the clean area, the area should be
cleaned, disinfected and/or sterilised where appropriate, before processing recommences if the
required standards of cleanliness and/or asepsis have not been maintained during the work.
35. Water treatment plants and distribution systems should be designed, constructed and
maintained so as to ensure a reliable source of water of an appropriate quality. They should not
be operated beyond their designed capacity. Water for injections should be produced, stored
and distributed in a manner which prevents microbial growth, for example by constant
circulation at a temperature above 70°C.
36. All equipment such as sterilisers, air handling and filtration systems, air vent and gas filters,
water treatment, generation, storage and distribution systems should be subject to validation
and planned maintenance; their return to use should be approved.
Sanitation
37. The sanitation of clean areas is particularly important. They should be cleaned thoroughly in
accordance with a written programme. Where disinfectants are used, more than one type
should be employed. Monitoring should be undertaken regularly in order to detect the
development of resistant strains.
38. Disinfectants and detergents should be monitored for microbial contamination; dilutions should
be kept in previously cleaned containers and should only be stored for defined periods unless
sterilised. Disinfectants and detergents used in Grades A and B areas should be sterile prior to
use.
39. Fumigation of clean areas may be useful for reducing microbiological contamination in
inaccessible places.
Processing
40. Precautions to minimise contamination should be taken during all processing stages including
the stages before sterilisation.
41. Preparations of microbiological origin should not be made or filled in areas used for the
processing of other medicinal products; however, vaccines of dead organisms or of bacterial
______________________________ Annex 1 Manufacture of sterile medicinal products n
extracts may be filled, after inactivation, in the same premises as other sterile medicinal
products.
42. Validation of aseptic processing should include a process simulation test using a nutrient
medium (media fill). Selection of the nutrient medium should be made based on dosage form of
the product and selectivity, clarity, concentration and suitability for sterilisation of the nutrient
medium. The process simulation test should imitate as closely as possible the routine aseptic
manufacturing process and include all the critical subsequent manufacturing steps. It should
also take into account various interventions known to occur during normal production as well as
worst case situations. Process simulation tests should be performed as initial validation with
three consecutive satisfactory simulation tests per shift and repeated at defined intervals and
after any significant modification to the HVAC-system, equipment, process and number of shifts.
Normally process simulation tests should be repeated twice a year per shift and process. The
number of containers used for media fills should be sufficient to enable a valid evaluation. For
small batches, the number of containers for media fills should at least equal the size of the
product batch. The target should be zero growth but a contamination rate of less than 0.1% with
95% confidence limit is acceptable. The manufacturer should establish alert and action limits.
Any contamination should be investigated.
43. Care should be taken that any validation does not compromise the processes.
44. Water sources, water treatment equipment and treated water should be monitored regularly for
chemical and biological contamination and, as appropriate, for endotoxins. Records should be
maintained of the results of the monitoring and of any action taken.
45. Activities in clean areas and especially when aseptic operations are in progress should be kept
to a minimum and movement of personnel should be controlled and methodical, to avoid
excessive shedding of particles and organisms due to over-vigorous activity. The ambient
temperature and humidity should not be uncomfortably high because of the nature of the
garments worn.
46. Microbiological contamination of starting materials should be minimal. Specifications should
include requirements for microbiological quality when the need for this has been indicated by
monitoring.
47. Containers and materials liable to generate fibres should be minimised in clean areas.
48. Where appropriate, measures should be taken to minimise the particulate contamination of the
end product.
49. Components, containers and equipment should be handled after the final cleaning process in
such a way that they are not recontaminated.
50. The interval between the washing and drying and the sterilisation of components, containers
and equipment as well as between their sterilisation and use should be minimised and subject
to a time-limit appropriate to the storage conditions.
51. The time between the start of the preparation of a solution and its sterilisation or filtration
through a micro-organism-retaining filter should be minimised. There should be a set maximum
permissible time for each product that takes into account its composition and the prescribed
method of storage.
52. The bioburden should be monitored before sterilisation. There should be working limits on
contamination immediately before sterilisation which are related to the efficiency of the method
to be used. Where appropriate the absence of pyrogens should be monitored. All solutions, in
particular large volume infusion fluids, should be passed through a micro-organism-retaining
filter, if possible sited immediately before filling.
53. Components, containers, equipment and any other article required in a clean area where
aseptic work takes place should be sterilised and passed into the area through double-ended
sterilisers sealed into the wall, or by a procedure which achieves the same objective of not
introducing contamination. Non-combustible gases should be passed through micro-organism
retentive filters.
______________________________ Annex 1 Manufacture of sterile medicinal products n
54. The efficacy of any new procedure should be validated, and the validation verified at scheduled
intervals based on performance history or when any significant change is made in the process
or equipment.
Sterilisation
55. All sterilisation processes should be validated. Particular attention should be given when the
adopted sterilisation method is not described in the current edition of the European
Pharmacopoeia, or when it is used for a product which is not a simple aqueous or oily solution.
Where possible, heat sterilisation is the method of choice. In any case, the sterilisation process
must be in accordance with the marketing and manufacturing authorisations.
56. Before any sterilisation process is adopted its suitability for the product and its efficacy in
achieving the desired sterilising conditions in all parts of each type of load to be processed
should be demonstrated by physical measurements and by biological indicators where
appropriate. The validity of the process should be verified at scheduled intervals, at least
annually, and whenever significant modifications have been made to the equipment. Records
should be kept of the results.
57. For effective sterilisation the whole of the material must be subjected to the required treatment
and the process should be designed to ensure that this is achieved.
58. Validated loading patterns should be established for all sterilisation processes .
59. Biological indicators should be considered as an additional method for monitoring the
sterilisation. They should be stored and used according to the manufacturers instructions, and
their quality checked by positive controls.
If biological indicators are used, strict precautions should be taken to avoid transferring
microbial contamination from them.
60. There should be a clear means of differentiating products which have not been sterilised from
those which have. Each basket, tray or other carrier of products or components should be
clearly labelled with the material name, its batch number and an indication of whether or not it
has been sterilised. Indicators such as autoclave tape may be used, where appropriate, to
indicate whether or not a batch (or sub-batch) has passed through a sterilisation process, but
they do not give a reliable indication that the lot is, in fact, sterile.
61. Sterilisation records should be available for each sterilisation run. They should be approved as
part of the batch release procedure.
Sterilisation by heat
62. Each heat sterilisation cycle should be recorded on a time/temperature chart with a sufficiently
large scale or by other appropriate equipment with suitable accuracy and precision. The position
of the temperature probes used for controlling and/or recording should have been determined
during the validation, and where applicable also checked against a second independent
temperature probe located at the same position.
______________________________ Annex 1 Manufacture of sterile medicinal products n
63. Chemical or biological indicators may also be used, but should not take the place of physical
measurements.
64. Sufficient time must be allowed for the whole of the load to reach the required temperature
before measurement of the sterilising time-period is commenced. This time must be determined
for each type of load to be processed.
65. After the high temperature phase of a heat sterilisation cycle, precautions should be taken
against contamination of a sterilised load during cooling. Any cooling fluid or gas in contact with
the product should be sterilised unless it can be shown that any leaking container would not be
approved for use.
Moist heat
66. Both temperature and pressure should be used to monitor the process. Control instrumentation
should normally be independent of monitoring instrumentation and recording charts. Where
automated control and monitoring systems are used for these applications they should be
validated to ensure that critical process requirements are met. System and cycle faults should
be registered by the system and observed by the operator. The reading of the independent
temperature indicator should be routinely checked against the chart recorder during the
sterilisation period. For sterilisers fitted with a drain at the bottom of the chamber, it may also be
necessary to record the temperature at this position, throughout the sterilisation period. There
should be frequent leak tests on the chamber when a vacuum phase is part of the cycle.
67. The items to be sterilised, other than products in sealed containers, should be wrapped in a
material which allows removal of air and penetration of steam but which prevents
recontamination after sterilisation. All parts of the load should be in contact with the sterilising
agent at the required temperature for the required time.
68. Care should be taken to ensure that steam used for sterilisation is of suitable quality and does
not contain additives at a level which could cause contamination of product or equipment.
Dry heat
69. The process used should include air circulation within the chamber and the maintenance of a
positive pressure to prevent the entry of non-sterile air. Any air admitted should be passed
through a HEPA filter. Where this process is also intended to remove pyrogens, challenge tests
using endotoxins should be used as part of the validation.
Sterilisation by radiation
70. Radiation sterilisation is used mainly for the sterilisation of heat sensitive materials and
products. Many medicinal products and some packaging materials are radiation-sensitive, so
this method is permissible only when the absence of deleterious effects on the product has
been confirmed experimentally. Ultraviolet irradiation is not normally an acceptable method of
sterilisation.
71. During the sterilisation procedure the radiation dose should be measured. For this purpose,
dosimetry indicators which are independent of dose rate should be used, giving a quantitative
measurement of the dose received by the product itself. Dosimeters should be inserted in the
load in sufficient number and close enough together to ensure that there is always a dosimeter
in the irradiator . Where plastic dosimeters are used they should be used within the time-limit of
their calibration. Dosimeter absorbances should be read within a short period after exposure to
radiation.
72. Biological indicators may be used as an additional control.
______________________________ Annex 1 Manufacture of sterile medicinal products n
73. Validation procedures should ensure that the effects of variations in density of the packages are
considered.
74. Materials handling procedures should prevent mix-up between irradiated and non-irradiated
materials. Radiation sensitive colour disks should also be used on each package to differentiate
between packages which have been subjected to irradiation and those which have not.
75. The total radiation dose should be administered within a predetermined time span.
Sterilisation with ethylene oxide
76. This method should only be used when no other method is practicable. During process
validation it should be shown that there is no damaging effect on the product and that the
conditions and time allowed for degassing are such as to reduce any residual gas and reaction
products to defined acceptable limits for the type of product or material.
77. Direct contact between gas and microbial cells is essential; precautions should be taken to
avoid the presence of organisms likely to be enclosed in material such as crystals or dried
protein. The nature and quantity of packaging materials can significantly affect the process.
78. Before exposure to the gas, materials should be brought into equilibrium with the humidity and
temperature required by the process. The time required for this should be balanced against the
opposing need to minimise the time before sterilisation.
79. Each sterilisation cycle should be monitored with suitable biological indicators, using the
appropriate number of test pieces distributed throughout the load. The information so obtained
should form part of the batch record.
80. For each sterilisation cycle, records should be made of the time taken to complete the cycle, of
the pressure, temperature and humidity within the chamber during the process and of the gas
concentration and of the total amount of gas used. The pressure and temperature should be
recorded throughout the cycle on a chart. The record(s) should form part of the batch record.
81. After sterilisation, the load should be stored in a controlled manner under ventilated conditions
to allow residual gas and reaction products to reduce to the defined level. This process should
be validated.
Filtration of medicinal products which cannot be sterilised in their
final container
82. Filtration alone is not considered sufficient when sterilisation in the final container is possible.
With regard to methods currently available, steam sterilisation is to be preferred. If the product
cannot be sterilised in the final container, solutions or liquids can be filtered through a sterile
filter of nominal pore size of 0.22 micron (or less), or with at least equivalent micro-organism
retaining properties, into a previously sterilised container. Such filters can remove most bacteria
and moulds, but not all viruses or mycoplasmas. Consideration should be given to
complementing the filtration process with some degree of heat treatment.
83. Due to the potential additional risks of the filtration method as compared with other sterilisation
processes, a second filtration via a further sterilised micro-organism retaining filter, immediately
prior to filling, may be advisable. The final sterile filtration should be carried out as close as
possible to the filling point.
84. Fibre shedding characteristics of filters should be minimal.
85. The integrity of the sterilised filter should be verified before use and should be confirmed
immediately after use by an appropriate method such as a bubble point, diffusive flow or
pressure hold test. The time taken to filter a known volume of bulk solution and the pressure
difference to be used across the filter should be determined during validation and any significant
differences from this during routine manufacturing, should be noted and investigated. Results of
these checks should be included in the batch record. The integrity of critical gas and air vent
______________________________ Annex 1 Manufacture of sterile medicinal products n
filters should be confirmed after use. The integrity of other filters should be confirmed at
appropriate intervals.
86. The same filter should not be used for more than one working day unless such use has been
validated.
87. The filter should not affect the product by removal of ingredients from it or by release of
substances into it.
Finishing of sterile products
88 Containers should be closed by appropriately validated methods. Containers closed by fusion,
e.g. glass or plastic ampoules should be subject to 100% integrity testing. Samples of other
containers should be checked for integrity according to appropriate procedures.
89. Containers sealed under vacuum should be tested for maintenance of that vacuum after an
appropriate, pre-determined period.
90. Filled containers of parenteral products should be inspected individually for extraneous
contamination or other defects. When inspection is done visually, it should be done under
suitable and controlled conditions of illumination and background. Operators doing the
inspection should pass regular eye-sight checks, with spectacles if worn, and be allowed
frequent breaks from inspection. Where other methods of inspection are used, the process
should be validated and the performance of the equipment checked at intervals. Results should
be recorded.
Quality control
91. The sterility test applied to the finished product should only be regarded as the last in a series of
control measures by which sterility is assured. The test should be validated for the product(s)
concerned.
92. In those cases where parametric release has been authorised, special attention should be paid
to the validation and the monitoring of the entire manufacturing process.
93. Samples taken for sterility testing should be representative of the whole of the batch, but should
in particular include samples taken from parts of the batch considered to be most at risk of
contamination, e.g.:
a. for products which have been filled aseptically, samples should include containers filled at
the beginning and end of the batch and after any significant intervention,
b. or products which have been heat sterilised in their final containers, consideration should
be given to taking samples from the potentially coolest part of the load.
______________________________ Annex 1 Manufacture of sterile medicinal products n