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Sterile Drug Products Produced by Aseptic Processing - Current Good Manufacturing Practice DRAFT GUIDANCE This guidance document is being distributed for comment purposes only. Comments and suggestions regarding this draft document should be submitted within 60 days of publication in the Federal Register of the notice announcing the availability of the draft guidance. Submit comments to Dockets Management Branch (HFA-305), Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. All comments should be identified with the docket number listed in the notice of availability that publishes in the Federal Register. For questions regarding this draft document contact (CDER) Richard Friedman, 301-594-0098; (CBER) Robert Sausville, 301-827-6201; (ORA) Robert Coleman, 404-253-1295. U.S. Department of Health and Human Services August 2003 Pharmaceutical CGMPs Additional copies are available from: Office of Training and Communication or Office of Communication, Training and August 2003 Pharmaceutical CGMPs TABLE OF CONTENTS A. Critical Area - Class 100 (ISO 5) V. PERSONNEL TRAINING, QUALIFICATION, & MONITORING VI. COMPONENTS AND CONTAINER/CLOSURES IX. VALIDATION OF ASEPTIC PROCESSING AND STERILIZATION 21 1. Study Design B. Filtration Efficacy 1. Sterilizer Qualification and Validation 1. General Written Program B. Microbiological Media and Identification
A. Choice of Methods XII. BATCH RECORD REVIEW: PROCESS CONTROL DOCUMENTATION APPENDIX 1: ASEPTIC PROCESSING ISOLATORS APPENDIX 2: BLOW-FILL- SEAL TECHNOLOGY APPENDIX 3: PROCESSING PRIOR TO FILLING AND SEALING OPERATIONS Guidance for Industry1
This draft guidance is intended to help manufacturers meet the requirements in the Agency's current good manufacturing practice (CGMP) regulations (2l CFR parts 210 and 211) when manufacturing sterile drug and biological products using aseptic processing. This guidance, when finalized, will replace the 1987 Industry Guideline on Sterile Drug Products Produced by Aseptic Processing. This revision updates and clarifies the 1987 guidance. For sterile drug products subject to a new or abbreviated drug application (NDA or ANDA), this guidance document should be read in conjunction with the 1994 guidance on the content of sterile drug applications, entitled Guideline for the Submission of Documentation for Sterilization Process Validation in Applications for Human and Veterinary Drug Products. The 1994 submission guidance describes the types of information and data that should be included in drug applications to demonstrate the efficacy of a manufacturer's sterilization process. This draft guidance compliments the 1994 guidance by describing procedures and practices that will help enable a sterile drug manufacturing facility to meet CGMP requirements relating, for example, to facility design, equipment suitability, process validation, and quality control. FDA's guidance documents, including this guidance, do not establish legally enforceable responsibilities. Instead, guidances describe the Agency's current thinking on a topic and should be viewed only as recommendations, unless specific regulatory or statutory requirements are cited. The use of the word should in Agency guidances means that something is suggested or recommended, but not required.
The text boxes included in this guidance discuss specific sections of parts 210 and 211 of the Code of Federal Regulations (CFR), which address current good manufacturing practice for drugs. The intent of including the citations in the text boxes is to aid the reader by providing a portion of an applicable regulation being addressed in the guidance. The citations included in the text boxes are not intended to be exhaustive. Readers of this document should reference the complete CFR to ensure that they have complied, in full, with all relevant sections of the regulations. This sections describes briefly both the regulatory and technical reasons why the Agency is developing this guidance document. This draft guidance pertains to current good manufacturing practice (CGMP) regulations (21 CFR parts 210 and 211) when manufacturing sterile drug and biological products using aseptic processing. For biological products regulated under 21 CFR parts 600 through 680, sections 210.2(a) and 211.1(b) provide that where it is impossible to comply with the applicable regulations in both parts 600 through 680 and parts 210 and 211, the regulation specifically applicable to the drug product in question shall apply. In the event that it is impossible to comply with all applicable regulations in these parts, the regulations specifically applicable to the drug in question shall supersede the more general. There are basic differences between the production of sterile drug products using aseptic processing and production using terminal sterilization. Terminal sterilization usually involves filling and sealing product containers under high-quality environmental conditions. Products are filled and sealed in this type of environment to minimize the microbial content of the in-process product and to help ensure that the subsequent sterilization process is successful. In most cases, the product, container, and closure have low bioburden, but they are not sterile. The product in its final container is then subjected to a sterilization process such as heat or irradiation. In an aseptic process, the drug product, container, and closure are first subjected to sterilization methods separately, as appropriate, and then brought together.2 Because there is no process to sterilize the product in its final container, it is critical that containers be filled and sealed in an extremely high-quality environment. Aseptic processing involves more variables than terminal sterilization. Before aseptic assembly into a final product, the individual parts of the final product are generally subjected to several sterilization processes. For example, glass containers are subjected to dry heat sterilization; rubber closures are subjected to moist heat sterilization; and liquid dosage forms are subjected to sterile filtration. Each of these aseptic manufacturing processes requires thorough validation and control. Each process also could introduce an error that ultimately could lead to the distribution of a contaminated product. Any manual or mechanical manipulation of the sterilized drug, components, containers, or closures prior to or during aseptic assembly poses the risk of contamination and thus necessitates careful control. A terminally sterilized drug product, on the other hand, undergoes a single sterilization process in a sealed container, thus limiting the possibilities for error.3 Manufacturers should have a keen awareness of the public health implications of distributing a nonsterile product. Poor CGMP conditions at a manufacturing facility can ultimately pose a life-threatening health risk to a patient. This guidance document discusses selected issues and does not address all aspects of aseptic processing. For example, the guidance addresses primarily finished drug product CGMP issues while only limited information is provided regarding upstream bulk processing steps. This guidance updates the 1987 guidance primarily with respect to personnel qualification, cleanroom design, process design, quality control, environmental monitoring, and review of production records. The use of isolators for aseptic processing is also discussed. Although this guidance document discusses CGMP issues relating to the sterilization of components, containers, and closures, terminal sterilization of drug products is not addressed. It is a well-accepted principle that sterile drugs should be manufactured using aseptic processing only when terminal sterilization is infeasible. However, some final packaging may afford some unique and substantial advantage (e.g., some dual-chamber syringes) that would not be possible if terminal sterilization were employed. In such cases, a manufacturer can explore the option of adding adjunct processing steps to increase the level of sterility confidence. A list of references that may be of value to the reader is included at the conclusion of this document.
As provided for in the regulations, aseptic processing facilities must have separate areas of operation that are appropriately controlled to attain different degrees of air quality depending on the nature of the operation. Design of a given area should be based on satisfying microbiological and particle standards defined by the equipment, components, and products exposed, as well as the particular operation conducted in the area. Critical areas and support areas of the aseptic processing operation should be classified and supported by microbiological and particle data obtained during qualification studies. Although initial cleanroom qualification should include some assessment of air quality under as-built and static conditions, the final room or area classification should be derived from data generated under dynamic conditions (i.e., with personnel present, equipment in place, and operations ongoing). The aseptic processing facility monitoring program should also assess conformance with specified clean area classifications under dynamic conditions on a routine basis. The following table summarizes clean area air classifications (Ref. 1). TABLE 1- Air Classificationsa
a- All classifications based on data measured in the vicinity of exposed materials/articles during periods of activity. b- ISO 14644-1 designations provide uniform particle concentration values for cleanrooms in multiple industries. An ISO 5 particle concentration is equal to Class 100 and approximately equals EU Grade A. c- Values represent recommended levels of environmental quality. You may find it appropriate to establish alternate microbiological levels due to the nature of the operation. d- The additional use of settling plates is optional. e- Samples from Class 100 (ISO 5) environments should normally yield no microbiological contaminants. Two clean areas are of particular importance to sterile drug product quality: the critical area and the supporting clean areas associated with it. A critical area is one in which the sterilized drug product, containers, and closures are exposed to environmental conditions designed to preserve sterility. Activities conducted in this area include manipulations (e.g., aseptic connections, sterile ingredient additions) of sterile materials prior to and during filling and closing operations. This area is critical because the product is not processed further in its immediate container and is vulnerable to contamination. To maintain product sterility, the environment in which aseptic operations (e.g., equipment setup, filling) are conducted should be of appropriate quality. One aspect of environmental quality is the particle content of the air. Particles are significant because they can enter a product and contaminate it physically or, by acting as a vehicle for microorganisms, biologically (Ref. 2). Particle content in critical areas should be minimized by appropriately designed air handling systems. Air in the immediate proximity of exposed sterilized containers/closures and filling/closing operations would be of appropriate particle quality when it has a per-cubic-meter particle count of no more than 3520 in a size range of 0.5 micron and larger when counted at representative locations normally not more than 1 foot away from the work site, within the airflow, and during filling/closing operations. This level of air cleanliness is also known as Class 100 (ISO 5). Deviations from this critical area monitoring parameter should be documented as to cause and significance. Measurements to confirm air cleanliness in aseptic processing zones should be taken with the particle counting probe oriented in the direction of oncoming airflow and at the sites where there is most potential risk to the exposed sterilized product and container-closures. Regular monitoring should be performed during each shift. Nonviable particle monitoring with a remote counting system is generally less invasive than the use of portable particle counting units and provides the most comprehensive data. See Section X.D. Particle Monitoring. Some powder filling operations can generate high levels of powder particles that, by their nature, do not pose a risk of product contamination. It may not, in these cases, be feasible to measure air quality within the one-foot distance and still differentiate background levels of powder particles from air contaminants. In these instances, air should be sampled in a manner that, to the extent possible, characterizes the true level of extrinsic particle contamination to which the product is exposed. Initial certification of the area under dynamic conditions without the actual powder filling function should provide some baseline information on the nonproduct particle generation of the operation. Air in critical areas should be supplied at the point of use as HEPA-filtered laminar flow air at a velocity sufficient to sweep particles away from the filling/closing area and maintain unidirectional airflow during operations. The velocity parameters established for each processing line should be justified and appropriate to maintain unidirectional airflow and air quality under dynamic conditions within a defined space (Ref. 3).4
Proper design and control should prevent turbulence or stagnant air in the aseptic processing line or clean area. Once relevant parameters are established, airflow patterns should be evaluated for turbulence or eddy currents that can act as a channel or reservoir for the accumulation of air contaminants (e.g., from an adjoining lower classified area). Air pattern analysis or smoke studies should be conducted that demonstrate unidirectional airflow and sweeping action over and away from the product under dynamic conditions. The studies should be well documented with written conclusions, including an evaluation of the impact of aseptic manipulations. Videotape or other recording mechanisms have been found to be useful in assessing airflow initially as well as facilitating evaluation of subsequent equipment configuration changes. However, even successfully qualified systems can be compromised by poor operational, maintenance or personnel practices. Air monitoring of critical areas should normally yield no microbiological contaminants. Contamination in this environment should receive investigative attention. Supporting clean areas can have various classifications and functions. Many support areas function as zones in which nonsterile components, formulated products, in-process materials, equipment, and container/closures are prepared, held, or transferred. These environments should be designed to minimize the level of particle contaminants in the final product and control the microbiological content (bioburden) of articles and components that are subsequently sterilized. The nature of the activities conducted in a supporting clean area should determine its classification. An area classified at Class 100,000 (ISO 8) would be used for less critical activities (such as initial equipment preparation). The area immediately adjacent to the aseptic processing line should, at a minimum, meet Class l0,000 (ISO 7) standards (see Table 1) under dynamic conditions. Depending on the operation, manufacturers can also classify this area as Class 1,000 (ISO 6) or maintain the entire aseptic filling room at Class 100 (ISO 5). Adequately separating areas of operation is an important part of contamination prevention. To maintain air quality in areas of higher cleanliness, it is important to achieve a proper airflow and a positive pressure differential relative to adjacent less clean areas. Rooms of higher air cleanliness should have a substantial positive pressure differential relative to adjacent rooms of lower air cleanliness. For example, a positive pressure differential of at least 12.5 Pascals (Pa)5 should be maintained at the interface between classified and unclassified areas. This same overpressure should be maintained between the aseptic processing room and adjacent rooms (with doors closed). When doors are open, outward airflow should be sufficient to minimize ingress of contamination, and the time that a door can remain ajar should be strictly controlled (Ref. 4). Pressure differentials between cleanrooms should be monitored continuously throughout each shift and frequently recorded, and deviations from established limits should be investigated. An adequate air change rate should be established for a cleanroom. For Class 100,000 (ISO 8) supporting rooms, airflow sufficient to achieve at least 20 air changes per hour would be typically acceptable. For areas of higher air cleanliness, significantly higher air change rates will provide an increased level of air purification. Facility monitoring systems should be established to rapidly detect atypical changes that can compromise the facility's environment. Operating conditions should be restored to established, qualified levels before reaching action levels. For example, pressure differential specifications should enable prompt detection (i.e., alarms) of an emerging low pressure problem to preclude ingress of unclassified air into a classified room. A compressed gas should be of appropriate purity (e.g., free from oil and water vapor) and its microbiological and particle quality should be equal to or better than air in the environment into which the gas is introduced. Compressed gases such as air, nitrogen, and carbon dioxide are often used in cleanrooms and are frequently employed in operations involving purging or overlaying. Membrane filters allow the filtering of compressed gases to meet an appropriate high-quality standard. Membrane filters can be used to produce a sterile compressed gas to conduct operations involving sterile materials, such as components and equipment. For example, sterile membrane filters should be used for autoclave air lines, lyophilizer vacuum breaks, and tanks containing sterilized materials. Sterilized holding tanks and any contained liquids should be held under continuous overpressure to prevent microbial contamination. Safeguards should be in place to prevent a pressure change that can result in contamination due to back flow of nonsterile air or liquid. Gas filters (including vent filters) should be dry. Condensate in a gas filter can cause blockage or microbial contamination. Use of hydrophobic filters, as well as application of heat to these filters where appropriate, prevents problematic moisture residues. Filters also should be integrity tested upon installation and periodically thereafter (e.g., including at end of use). Integrity test failures should be investigated, and filters should be replaced at appropriate intervals. 2. High-Efficiency Particulate Air (HEPA)6 An essential element in ensuring aseptic conditions is the maintenance of HEPA filter integrity. Leak testing should be performed at installation to detect integrity breaches around the sealing gaskets, through the frames, or through various points on the filter media. Thereafter, leak tests should be performed at suitable time intervals for HEPA filters in the aseptic processing facility. For example, such testing should be performed twice a year for the aseptic processing room. Additional testing may be appropriate when air quality is found to be unacceptable, facility renovations might be the cause of disturbances to ceiling or wall structures, or as part of an investigation into a media fill or drug product sterility failure. Among the filters that should be leak tested are those installed in dry heat depyrogenation tunnels commonly used to depyrogenate glass vials. Any aerosol used for challenging a HEPA filter should meet specifications for critical physicochemical attributes such as viscosity. Dioctylphthalate (DOP) and Poly-alpha-olefin (PAO) are examples of appropriate leak testing aerosols. Some alternative aerosols are problematic because they pose the risk of microbial contamination of the environment being tested. Firms should ensure that any alternative used does not promote microbial growth. There is a major difference between filter leak testing and efficiency testing. An efficiency test is a general test used to determine only the rating of the filter.7 An intact HEPA filter should be capable of retaining at least 99.97 percent of particulates greater than 0.3 micron in diameter. The purpose of performing regularly scheduled leak tests, on the other hand, is to detect leaks from the filter media, filter frame, or seal. The challenge should be conducted using a polydispersed aerosol usually composed of particles with a light-scattering mean droplet diameter in the submicron size range, including a sufficient number of particles at approximately 0.3 microns. Performing a leak test without introducing a sufficient upstream challenge of particles of known size upstream of the filter is ineffective for detecting leaks. For example, depending on the accuracy of the photometer, a DOP challenge should introduce the aerosol upstream of the filter in a concentration ranging from approximately 25 to l00 micrograms/liter of air at the filter's designed airflow rating. The leak test should be done in place, and the filter face scanned on the downstream side with an appropriate photometer probe, at a sampling rate of at least one cubic foot per minute. The downstream leakage measured by the probe should then be calculated as a percent of the upstream challenge. Scanning should be conducted on the entire filter face and frame at a position about one to two inches from the face of the filter. This comprehensive scanning of HEPA filters should be fully documented. A single probe reading equivalent to 0.01 percent of the upstream challenge should be considered as indicative of a significant leak and should result in replacement of the HEPA filter or, when appropriate, repair in a limited area. A subsequent confirmatory re-test should be performed in the area of any repair. HEPA filter leak testing alone is not sufficient to monitor filter performance. This testing is usually done only on a semi-annual basis. It is important to conduct periodic monitoring of filter attributes such as uniformity of velocity across the filter (and relative to adjacent filters). Variations in velocity generally increase the possibility of contamination, as these changes (e.g., velocity reduction) can have an effect on unidirectional airflow. Airflow velocities are measured 6 inches from the filter face and at a defined distance proximal to the work surface for HEPA filters in the critical area. Regular velocity monitoring can provide useful data on the clean area in which aseptic processing is performed. HEPA filters should be replaced when nonuniformity of air velocity across an area of the filter is detected or airflow patterns may be adversely affected. Although vendors often provide these services, drug manufacturers are responsible for ensuring that these essential certification activities are conducted satisfactorily.
Aseptic processes are designed to minimize exposure of sterile articles to the potential contamination hazards of the manufacturing operation. Limiting the duration of exposure of sterile product elements, providing the highest possible environmental control, optimizing process flow, and designing equipment to prevent entrainment of lower quality air into the Class 100 (ISO 5) clean area are essential to achieving high assurance of sterilty (Ref. 4). Both personnel and material flow should be optimized to prevent unnecessary activities that could increase the potential for introducing contaminants to exposed product, container-closures, or the surrounding environment. The layout of equipment should provide for ergonomics that optimize comfort and movement of operators. The number of personnel in an aseptic processing room should be minimized. The flow of personnel should be designed to limit the frequency with which entries and exits are made to and from an aseptic processing room and, most significantly, its critical area. Regarding the latter, the number of transfers into an isolator, or into the critical area of a traditional clean room, should be minimized. To prevent changes in air currents that introduce lower quality air, movement adjacent to the critical area should be appropriately restricted. Any intervention or stoppage during an aseptic process can increase the risk of contamination. The design of equipment used in aseptic processing should limit the number and complexity of aseptic interventions by personnel. For example, personnel intervention can be reduced by integrating an on-line weight check device, thus eliminating a repeated manual activity within the critical area. Rather than performing an aseptic connection, sterilizing the prefastened connection using sterilize-in-place (SIP) technology also can eliminate a significant aseptic manipulation. Automation of other process steps, including the use of technologies such as robotics, can further reduce risk to the product. Transfer of products should be performed under appropriate cleanroom conditions. For example, lyophilization processes include transfer of aseptically filled product in partially sealed containers. To prevent contamination, partially closed sterile product should be transferred only in critical areas. Facility design should ensure that the area between a filling line and the lyophilizer and the transport and loading procedures provide Class 100 (ISO 5) protection. The sterile drug product and container closures should be protected by equipment of suitable design. Carefully designed curtains, rigid plastic shields, or other barriers should be used in appropriate locations to achieve significant segregation of the aseptic processing line. Use of an isolator system further enhances product protection (see Appendix 1). Due to the interdependence of the various rooms that make up an aseptic processing facility, it is essential to carefully define and control the dynamic interactions permitted between cleanrooms. Use of a double-door or integrated sterilizer is valuable in ensuring direct product flow, often from a lower to a higher classified area. Airlocks and interlocking doors facilitate better control of air balance throughout the aseptic processing facility. Airlocks should be installed between the aseptic processing area entrance and the adjoining uncontrolled area. Other interfaces such as personnel transitions or material staging areas are appropriate locations for air locks. It is critical to adequately control material (e.g., in-process supplies, equipment, utensils) as it transfers from lesser to higher controlled clean areas to prevent the influx of contaminants. For example, written procedures should address how materials should be introduced into the aseptic processing room to ensure that room conditions are not compromised. In this regard, materials should be disinfected in accord with appropriate procedures. Cleanrooms are normally designed as functional units with specific purposes. A well-designed cleanroom is constructed with materials that allow for ease of cleaning and sanitizing. Examples of adequate design features include seamless and rounded floor to wall junctions as well as readily accessible corners. Floors, walls, and ceilings are constructed of smooth, hard surfaces that can be easily cleaned (211.42). Ceilings and associated HEPA filter banks should be designed to protect sterile materials from contamination. Cleanrooms also should not contain unnecessary equipment, fixtures, or materials. Processing equipment and systems should be equipped with sanitary fittings and valves. With rare exceptions, drains are not considered appropriate for classified areas of the aseptic processing facility. When applicable, equipment should be suitably designed for ease of sterilization (211.63). Ease of installation to facilitate aseptic setup is also an important consideration. The effect of equipment design on the cleanroom environment should be addressed. Flat surfaces or ledges that accumulate particles should be avoided. Equipment should not obstruct airflow and, in critical areas, its design should not perturb airflow. Deviation or change control systems should address atypical conditions posed by shutdown of air handling systems or other utilities, and the impact of construction activities on facility control. V. PERSONNEL TRAINING, QUALIFICATION, & MONITORING
A well-designed aseptic process minimizes personnel intervention. As operator activities increase in an aseptic processing operation, the risk to finished product sterility also increases. To ensure maintenance of product sterility, operators involved in aseptic manipulations should adhere to the basic principles of aseptic technique at all times. Appropriate training should be conducted before an individual is permitted to enter the aseptic processing area and perform operations. For example, such training should include aseptic technique, cleanroom behavior, microbiology, hygiene, gowning, patient safety hazards posed by a nonsterile drug product, and the specific written procedures covering aseptic processing area operations. After initial training, personnel should be updated regularly by an ongoing training program. Supervisory personnel should routinely evaluate each operator's conformance to written procedures during actual operations. Similarly, the quality control unit should provide regular oversight of adherence to established, written procedures and basic aseptic techniques during manufacturing operations. Some of these techniques aimed at maintaining sterility of sterile items and surfaces include: · Contacting sterile materials only with sterile instruments
Sterile instruments (e.g., forceps) should always be used in the handling of sterilized materials. Between uses, instruments should be placed only in sterilized containers. Instruments should be replaced as necessary throughout an operation. After initial gowning, sterile gloves should be regularly sanitized to minimize the risk of contamination. Personnel should not directly contact sterile products, containers, closures, or critical surfaces. · Moving slowly and deliberately Rapid movements can create unacceptable turbulence in the critical zone. Such movements disrupt the sterile field, presenting a challenge beyond intended cleanroom design and control parameters. The principle of slow, careful movement should be followed throughout the cleanroom. · Keeping the entire body out of the path of unidirectional air Unidirectional airflow design is used to protect sterile equipment surfaces, container-closures, and product. Personnel should not disrupt the path of unidirectional flow air in the aseptic processing zone. · Approaching a necessary manipulation in a manner that does not compromise sterility of the product To maintain sterility of nearby sterile materials, a proper aseptic manipulation should be approached from the side and not above the product (in vertical unidirectional flow operations). Also, an operator should refrain from speaking when in direct proximity to an aseptic processing line. · Maintaining Proper Gown Control Prior to and throughout aseptic operations, an operator should not engage in any activity that poses an unreasonable contamination risk to the gown. Only personnel who have been qualified and appropriately gowned should be permitted access to the aseptic processing area. An aseptic processing area gown should provide a barrier between the body and exposed sterilized materials and prevent contamination from particles generated by, and microorganisms shed from, the body. Gowns should be sterile and nonshedding and should cover the skin and hair (face-masks, hoods, beard/moustache covers, protective goggles, elastic gloves, cleanroom boots, and shoe overcovers are examples of common elements of gowns). Written procedures should detail the methods used to don each gown component in an aseptic manner. An adequate barrier should be created by the overlapping of gown components (e.g., gloves overlapping sleeves). If an element of a gown is found to be torn or defective, it should be changed immediately. There should be an established program to regularly assess or audit conformance of personnel to relevant aseptic manufacturing requirements. An aseptic gowning qualification program should assess the ability of a cleanroom operator to maintain the quality of the gown after performance of gowning procedures. Gowning qualification should include microbiological surface sampling of several locations on a gown (e.g., glove fingers, facemask, forearm, chest, other sites). Following an initial assessment of gowning, periodic requalification should monitor various gowning locations over a suitable period to ensure the consistent acceptability of aseptic gowning techniques. Semi-annual or yearly requalification is sufficient for automated operations where personnel involvement is minimized. To protect exposed sterilized product, personnel should be expected to maintain gown quality and strictly adhere to appropriate aseptic method. Written procedures should adequately address circumstances under which personnel should be retrained, requalified, or reassigned to other areas. The basic principles of training, aseptic technique, and personnel qualification in aseptic manufacturing also are applicable to those performing aseptic sampling and microbiological laboratory analyses. Processes and systems cannot be considered to be in control and reproducible if the validity of data produced by the laboratory is in question. Personnel can significantly affect the quality of the environment in which the sterile product is processed. A vigilant and responsive personnel monitoring program should be established. Monitoring should be accomplished by obtaining surface samples of each operator's gloves on a daily basis, or in association with each batch. This sampling should be accompanied by an appropriate sampling frequency for other strategically selected locations of the gown (Ref. 5). The quality control unit should establish a more comprehensive monitoring program for operators involved in operations which are especially labor intensive (i.e., those requiring repeated or complex aseptic manipulations). Asepsis is fundamental to an aseptic processing operation. An ongoing goal for manufacturing personnel in the aseptic processing room is to maintain contamination-free gloves throughout operations. Sanitizing gloves just prior to sampling is inappropriate because it can prevent recovery of microorganisms that were present during an aseptic manipulation. When operators exceed established levels or show an adverse trend, an investigation should be conducted promptly. Follow-up actions can include increased sampling, increased observation, retraining, gowning requalification, and in certain instances, reassignment of the individual to operations outside of the aseptic processing area. Microbiological trending systems, and assessment of the impact of atypical trends, are discussed in more detail under Section XI. Laboratory Controls. VI. COMPONENTS AND CONTAINER/CLOSURES
A drug product produced by aseptic processing can become contaminated through the use of one or more components (e.g., active ingredients, excipients, Water for Injection) that are contaminated with microorganisms or endotoxins. It is important to characterize the microbial content of each component that could be contaminated and establish appropriate acceptance limits based on information on bioburden. Knowledge of bioburden is critical in assessing whether the sterilization process is adequate. In aseptic processing, each component is individually sterilized or several components are combined, with the resulting mixture sterilized.8 There are several methods for sterilizing components (see relevant discussion in Section IX). A widely used method is filtration of a solution formed by dissolving the component(s) in a solvent such as USP Water for Injection (WFI). The solution is passed through a sterilizing membrane or cartridge filter. Filter sterilization is used where the component is soluble and is likely to be adversely affected by heat. A variation of this method involves subjecting the filtered solution to aseptic crystallization and precipitation (or lyophilization) of the component as a sterile powder. However, this method involves more handling and manipulation and therefore has a higher potential for contamination during processing. If a component is not adversely affected by heat, and is soluble, it can be made into a solution and subjected to steam sterilization, typically in an autoclave or a fixed pressurized sterilize-in-place (SIP) vessel. Dry heat sterilization is a suitable method for components that are heat stable and insoluble. However, carefully designed heat penetration and distribution studies should be performed for powder sterilization because of the insulating effects of the powder. Ethylene oxide (EtO) exposure is often used for surface sterilization, and for sterilizing certain packages with porous overwrapping. Such methods should be carefully controlled and validated if used for powders to evaluate whether consistent penetration of the sterilant can be achieved and to minimize residual ethylene oxide and by-products. Parenteral products are intended to be nonpyrogenic. There should be written procedures and appropriate specifications for acceptance or rejection of each lot of components that might contain endotoxins. Any components failing to meet defined endotoxin limits should be rejected.
Containers and closures should be rendered sterile and, for parenteral drug products, pyrogen-free. The type of processes used will depend primarily on the nature of the container and/or closure materials. The validation study for such a process should be adequate to demonstrate its ability to render materials sterile and pyrogen-free. Written procedures should specify the frequency of revalidation of these processes as well as time limits for holding sterile, depyrogenated containers and closures. Presterilization preparation of glass containers usually involves a series of wash and rinse cycles. These cycles serve an important role in removing foreign matter. Rinse water should be of high purity so as not to contaminate containers. For parenteral products, final rinse water should meet the specifications of Water for Injection, USP. The adequacy of the depyrogenation process can be assessed by spiking containers or closures with known quantities of endotoxin, followed by measuring endotoxin content after depyrogenation. The challenge studies should be performed with a reconstituted endotoxin solution applied directly onto the surface being tested and air-dried. Positive controls should be used to measure the percentage of endotoxin recovery by the test method. Validation study data should demonstrate that the process reduces the endotoxin content by at least 99.9 percent (3 logs) (see Section VII). Glass containers are generally subjected to dry heat for sterilization and depyrogenation. Validation of dry heat sterilization and depyrogenation should include appropriate heat distribution and penetration studies as well as the use of worst-case process cycles, container characteristics (e.g., mass), and specific loading configurations to represent actual production runs. See Section IX.C. Pyrogen on plastic containers can be generally removed by multiple WFI rinses. Plastic containers can be sterilized with an appropriate gas, irradiation, or other suitable means. For gases such as EtO, the parameters and limits of the EtO sterilization cycle (e.g. temperature, pressure, humidity, gas concentration, exposure time, degassing, aeration, and determination of residuals) should be specified and monitored closely. Biological indicators are of special importance in demonstrating the effectiveness of EtO and other gas sterilization processes. Rubber closures (e.g., stoppers and syringe plungers) can be cleaned by multiple cycles of washing and rinsing prior to final steam or irradiation sterilization. At minimum, the initial rinses for the washing process should employ Purified Water, USP, of minimal endotoxin content, followed by final rinse(s) with WFI for parenteral products. Normally, depyrogenation is achieved by multiple rinses of hot WFI. The time between washing, drying (where appropriate), and sterilizing should be minimized because residual moisture on the stoppers can support microbial growth and the generation of endotoxins. Because rubber is a poor conductor of heat, extra attention should be given to the validation of processes that use heat with respect to its penetration into the rubber stopper load (See Section XI.C). Validation data from the washing procedure should demonstrate successful endotoxin removal from rubber materials. A potential source of contamination is the siliconization of rubber stoppers. Silicone used in the preparation of rubber stoppers should meet appropriate quality control criteria and not have an adverse effect on the safety, quality, or purity of the drug product. Contract facilities that perform sterilization and/or depyrogenation of containers and closures are subject to the same CGMP requirements as those established for in-house processing. The finished dosage form manufacturer is responsible for the review and approval of the contractor's validation protocol and final validation report. A container closure system that permits penetration of air, or microorganisms, is unsuitable for a sterile product. Any damaged or defective units should be detected, and removed, during inspection of the final sealed product. Safeguards should be implemented to strictly preclude shipment of product that may lack container closure integrity and lead to nonsterility. Equipment suitability problems or incoming container or closure deficiencies have caused loss of container closure system integrity. As examples, failure to detect vials fractured by faulty machinery, or by mishandling of bulk finished stock, has led to drug recalls. If damage that is not readily detected leads to loss of container closure integrity, improved procedures should be rapidly implemented to prevent and detect such defects. Functional defects in delivery devices (e.g., syringe device defects, delivery volume) can also result in product quality problems and should be monitored by appropriate in-process testing. Any defects or results outside the specifications established for in-process and final inspection should be investigated in accord with Section 211.192.
Endotoxin contamination of an injectable product can be a result of poor CGMP controls. Certain patient populations (e.g., neonates), those receiving other injections concomitantly, or those administered a parenteral in atypically large volumes or doses can be at greater risk for pyrogenic reaction than anticipated by the established limits based on body weight of a normal healthy adult (Ref. 6, 7). Such clinical concerns reinforce the need for appropriate CGMP controls to prevent generation of endotoxin. Drug product components, container closures, equipment, and storage time limitations are among the areas to address in establishing endotoxin control. Adequate cleaning, drying, and storage of equipment provides for control of bioburden and prevents contribution of endotoxin load. Equipment should be designed to be easily assembled and disassembled, cleaned, sanitized, and/or sterilized. Endotoxin control should be exercised for all product contact surfaces both prior to and after sterile filtration. Endotoxin on equipment surfaces is inactivated by high-temperature dry heat, or removed from equipment surfaces by validated cleaning procedures. Some clean-in-place procedures employ initial rinses with appropriate high purity water and/or a cleaning agent (e.g., acid, base, surfactant), followed by final rinses with heated WFI. Equipment should be dried following cleaning. Sterilizing-grade filters and moist heat sterilization have not been shown to be effective in removing endotoxins. Processes that are designed to achieve depyrogenation should demonstrate a 3-log reduction of endotoxin.
Time limits should be established for each phase of aseptic processing. Time limits should include, for example, the period between the start of bulk product compounding and its filtration, filtration processes, product exposure while on the processing line, and storage of sterilized equipment, containers and closures. Maintenance of in-process quality at different production phases should be supported by data. Bioburden and endotoxin load should be assessed when establishing time limits for stages such as the formulation processing stage. The total time for product filtration should be limited to an established maximum to prevent microorganisms from penetrating the filter. Such a time limit should also prevent a significant increase in upstream bioburden and endotoxin load. Sterilizing-grade filters should generally be replaced following each manufactured lot. Because they can provide a substrate for microbial attachment, maximum use times for those filters used upstream for solution clarification or particle removal should also be established and justified. IX. VALIDATION OF ASEPTIC PROCESSING AND STERILIZATION
This section primarily discusses routine qualification and validation study recommendations. Change control procedures are addressed only briefly, but are an important part of the quality systems established by a firm. As noted above, a change in equipment, process, test method, or systems should be evaluated through the written change control program and should trigger an evaluation of the need for revalidation or requalification. To ensure the sterility of products purporting to be sterile, both sterilization and aseptic filling and closing operations must be adequately validated (211.113). The goal of even the most effective sterilization processes can be defeated if the sterilized elements of a product (the drug, the container, and the closure) are brought together under conditions that contaminate any of those elements. Similarly, product sterility will be compromised if product elements are not sterile when they are assembled. The validation of an aseptic processing operation should include the use of a microbiological growth nutrient medium in place of the product. This has been termed a media fill or process simulation. In the normal media fill simulation, the nutrient medium should be exposed to product contact surfaces of equipment, container closure systems, critical environments, and process manipulations to closely simulate the same exposure that the product itself will undergo. The sealed containers filled with the media are then incubated to detect microbial contamination. The results should be interpreted to determine the potential for a unit of drug product to become contaminated during actual operations (e.g., start-up, sterile ingredient additions, aseptic connections, filling, closing). Environmental monitoring data from the process simulation can also provide useful information for the processing line evaluation. A recommended media fill program incorporates the contamination risk factors that occur on a production line, and accurately assesses the state of process control. Media fill studies should simulate aseptic manufacturing operations as closely as possible, incorporating a worst-case approach. The media fill program should address applicable issues such as: · factors associated with the longest permitted run on the processing line · number and type of normal interventions, atypical interventions, unexpected events (e.g., maintenance), stoppages, equipment adjustments or transfers · lyophilization, when applicable · aseptic assembly of equipment (e.g., at start-up, during processing) · number of personnel and their activities · number of aseptic additions (e.g., charging containers and closures as well as sterile ingredients) · shift changes, breaks, and gown changes (when applicable) · number and type of aseptic equipment disconnections/connections · aseptic sample collections · line speed and configurations · manual weight checks · operator fatigue · container closure systems (e.g., sizes, type, compatibility with equipment) · specific provisions of aseptic processing related Standard Operating Procedures (e.g., conditions permitted before line clearance is mandated) A written batch record, documenting production conditions and simulated activities, should be prepared for each media fill run. The same vigilance should be observed in both media fill and routine production runs. Media fills should not be used to justify an unacceptable practice. When a processing line is initially qualified, separate media fills should be repeated enough times to ensure that results are consistent and meaningful. This approach is important because a single run can be inconclusive, while multiple runs with divergent results signal a process that is not in control. At least three consecutive separate successful runs should be performed during initial line qualification. Subsequently, routine semi-annual qualification should be conducted for each processing line to evaluate the state of control of the aseptic process. Activities and interventions representative of each shift, and shift changeover, should be incorporated into the design of the semi-annual qualification. For example, the evaluation of a shift should address its unique time-related and operational features. All personnel who enter the aseptic processing area, including technicians and maintenance personnel, should participate in a media fill at least once a year. Participation should be consistent with the nature of each operator's duties during routine production. Each change to a product or line change should be evaluated using a written change control system. Any changes or events that have the potential to affect the ability of the aseptic process to exclude contamination from the sterilized product should be assessed through additional media fills. For example, facility and equipment modifications, line configuration changes, significant changes in personnel, anomalies in environmental testing results, container closure system changes or, end product sterility testing showing contaminated products may be cause for revalidation of the system. Where data from a media fill indicate the process may not be in control, a comprehensive documented investigation should be conducted to determine the origin of the contamination and the scope of the problem. Once corrections are instituted, repeat process simulation runs should be performed to confirm that deficiencies in practices and procedures have been corrected and the process has returned to a state of control. When an investigation fails to reach well-supported, substantive conclusions as to the cause of the media fill failure, three consecutive successful runs and increased scrutiny (e.g., extra supervision, monitoring) of the production process should be implemented. The duration of aseptic processing operations is a major consideration in determining the size of the media fill run. Although the most accurate simulation model would be the full batch size and duration because it most closely simulates the actual production run, other appropriate models can be justified. In any study protocol, the duration of the run and the overall study design should adequately mimic worst-case operating conditions and cover all manipulations that are performed in the actual processing operation. In this regard, interventions that commonly occur should be routinely simulated, while those occurring rarely can be simulated periodically. While conventional manufacturing lines are highly automated, often operate at relatively high speeds, and are designed to limit operator intervention, there are some processes that include considerable operator involvement. When aseptic processing employs manual filling or closing, or extensive manual manipulations, the duration of the process simulation should generally be no less than the length of the actual manufacturing process to best simulate contamination risks posed by operators. For lyophilization operations, unsealed containers should be exposed to pressurization and partial evacuation of the chamber in a manner that simulates the process. Vials should not be frozen, as this may inhibit the growth of microorganisms. The simulation run sizes should be adequate to mimic commercial production conditions and accurately assess the potential for commercial batch contamination. The number of units filled during the process simulation should be based on contamination risk for a given process and sufficient to accurately simulate activities that are representative of the manufacturing process. A generally acceptable starting point for run size is in the range of 5,000 to 10,000 units. For operations with production sizes under 5,000, the number of media filled units should equal the maximum batch size made on the processing line (Ref. 8). When the possibility of contamination is higher based on the process design (e.g., manually intensive filling lines), a larger number of units, generally at or approaching the full production batch size, should be used. In contrast, a process conducted in an isolator (see Appendix 1) can have a low risk of contamination because of the lack of direct human intervention and can be simulated with a lower number of units as a proportion of the overall operation. Some batches are produced over multiple shifts or yield an unusually large number of units, and media fill size and duration are especially important considerations in the media fill protocol. These factors should be carefully considered when designing the simulation to adequately encompass conditions and any potential risks associated with the larger operation. The media fill program should adequately address the range of line speeds (e.g., by bracketing all vial sizes and fill volumes) employed during production. Each individual media fill run should evaluate a single worst-case line speed, and the speed chosen for each run during a study should be justified. For example, use of high line speed is often most appropriate in the evaluation of manufacturing processes characterized by frequent interventions or a significant degree of manual manipulation. Use of slow line speed is generally appropriate for evaluating manufacturing processes characterized by prolonged exposure of the sterile drug product and container closures in the aseptic area. Media fills should be adequately representative of the range of conditions under which actual manufacturing operations are conducted. An inaccurate assessment (making the process appear cleaner than it actually is) can result from conducting a media fill under extraordinary air particulate and microbial quality, or under production controls and precautions taken in preparation for the media fill. To the extent standard operating procedures permit stressful conditions, it is important that media fills include analogous challenges to support the validity of these studies. In general, a microbiological growth medium, such as soybean casein digest medium, should be used. Use of anaerobic growth media (e.g., fluid thioglycollate medium) would be appropriate in special circumstances. The media selected should be demonstrated to promote growth of USP <71> indicator microorganisms as well as representative isolates identified by environmental monitoring, personnel monitoring, and positive sterility test results. Positive control units should be inoculated with a <100 CFU challenge and incubated. For those instances in which the growth promotion testing fails, the origin of any contamination found during the simulation should nonetheless be investigated, and the media fill should be promptly repeated. The production process should be accurately simulated using media and conditions that optimize detection of any microbiological contamination. Each unit should be filled with an appropriate quantity and type of microbial growth medium to contact the inner container closure surfaces (when the unit is inverted or thoroughly swirled) and permit visual detection of microbial growth. Some drug manufacturers have expressed concern over the possible contamination of the facility and equipment with the nutrient media during media fill runs. However, if the medium is handled properly and is promptly followed by the cleaning, sanitizing, and, where necessary, sterilization of equipment, subsequently processed products are not likely to be compromised. Media units should be incubated under conditions adequate to detect organisms that can otherwise be difficult to culture. Incubation conditions should be established in accord with the following general guidelines: · Incubation temperature should be suitable for recovery of bioburden and environmental isolates and should at no time be outside the range of 20-35oC. Incubation temperature should be maintained within 2.5oC of the target temperature. · Incubation time should not be less than 14 days. If two temperatures are used for the incubation of the media filled samples, the samples should be incubated for at least 7 days at each temperature. Each media-filled unit should be examined for contamination by personnel with appropriate education, training, and experience in microbiological techniques. There should be direct quality control unit oversight throughout any such examination. Clear containers with otherwise identical physical properties should be used as a substitute for amber or other opaque containers to allow visual detection of microbial growth. When a firm performs a final product inspection of units immediately following the media fill run, all integral units should proceed to incubation. Units found to have defects not related to integrity (e.g., cosmetic defect) should be incubated; units that lack integrity should be rejected. Erroneously rejected units should be returned promptly for incubation with the media fill lot. After incubation is underway, any unit found to be damaged should be included in the data for the media fill run, because the incubation of the units simulates release to the market. Any decision to exclude such incubated units (i.e., nonintegral) from the final run tally should be fully justified and the deviation explained in the media fill report. If a correlation emerges between difficult to detect damage and microbial contamination, a thorough investigation should be conducted to determine its cause (see Section VI.B). Written procedures regarding aseptic interventions should be clear and specific (e.g., intervention type; quantity of units removed), providing for consistent production practices and assessment of these practices during media fills. If written procedures and batch documentation are adequate, these intervention units do not need to be incubated during media fills.9 Where procedures lack specificity, there would be insufficient justification for exclusion of units removed during an intervention from incubation. As an example, if a production procedure requires removal of 10 units after an intervention at the stoppering station infeed, batch records (i.e., for production and media fills) should clearly document conformance with this procedure. In no case should more units be removed during a media fill intervention than would be cleared during a production run. The ability of a media fill run to detect potential contamination from a given simulated activity should not be compromised by a large-scale line clearance, which can result in removal of a positive unit caused by an unrelated event or intervention. If unavoidable, appropriate study provisions should be made to compensate in such instances. Appropriate criteria should be established for yield and accountability. Media fill record reconciliation documentation should include a full accounting and description of units rejected from a batch. The process simulation run should be observed, and contaminated units should be reconcilable with the approximate time and the activity being simulated during the media fill. Video recording of a media fill has been found to be useful in identifying personnel practices that could negatively impact the aseptic process. Any contaminated unit should be considered as objectionable and fully investigated. The microorganisms should be identified to species level. In the case of a media fill failure, a comprehensive investigation should be conducted, surveying all possible causes of the contamination. The effects on commercial drugs produced on the line since the last successful media fill should also be assessed. Whenever contamination exists in a media fill run, it should be considered indicative of a potential sterility assurance problem, regardless of run size. The number of contaminated units should not be expected to increase in a directly proportional manner with the number of vials in the media fill run. Test results should reliably and reproducibly show that the units produced by an aseptic processing operation are sterile. Modern aseptic processing operations in suitably designed facilities have demonstrated a capability of meeting contamination levels approaching zero (Ref. 8, 9) and should normally yield no media fill contamination. Recommended criteria for assessing state of aseptic line control are as follows: · When filling fewer than 5000 units, no contaminated units should be detected. · When filling from 5,000 to 10,000 units: -- 1 contaminated unit should result in an investigation, including consideration of a repeat media fill. -- 2 contaminated units are considered cause for revalidation, following investigation. · When filling more than 10,000 units: -- 1 contaminated unit should result in an investigation. -- 2 contaminated units are considered cause for revalidation, following investigation. For any run size, intermittent incidents of microbial contamination in media filled runs can be indicative of a persistent low-level contamination problem that should be investigated. Accordingly, recurring incidents of contaminated units in media fills for an individual line, regardless of acceptance criteria, would be a signal of an adverse trend on the aseptic processing line that should lead to problem identification, correction, and revalidation. A firm's use of media fill acceptance criteria allowing infrequent contamination does not mean that a distributed lot of drug product purporting to be sterile may contain a nonsterile unit. The purpose of an aseptic process is to prevent any contamination. A manufacturer is fully liable for the shipment of any nonsterile unit, an act that is prohibited under the FD&C Act (§ 301(a) 21 U.S.C. 331(a)). FDA also recognizes that there might be some scientific and technical limitations on how precisely and accurately validation can characterize a system of controls intended to exclude contamination. As with any validation run, it is important to note that invalidation of a media fill run should be a rare occurrence. A media fill run should be aborted only under circumstances in which written procedures require commercial lots to be equally handled. Supporting documentation and justification should be provided in such cases. Filtration is a common method of sterilizing drug product solutions. An appropriate sterilizing grade filter is one that reproducibly removes all microorganisms from the process stream, producing a sterile effluent. Such filters usually have a rated porosity of 0.2 micron or smaller. Whatever filter or combination of filters is used, validation should include microbiological challenges to simulate worst-case production conditions regarding the size of microorganisms in the material to be filtered and integrity test results of the filters used for the study. The microorganisms should be small enough to both challenge the nominal porosity of the filter and simulate the smallest microorganism that may occur in production. The microorganism Brevundimonas diminuta (ATCC 19146) when properly grown, harvested and used, can be satisfactory in this regard because it is one of the smallest bacteria (0.3 micron mean diameter). Bioburden of unsterilized bulk solutions should be determined to trend the characteristics of potentially contaminating organisms. In certain cases, when justified as equivalent or better than use of Brevundimonas diminuta, it may be appropriate to conduct bacterial retention studies with a bioburden isolate. The number of microorganisms in the challenge is important because a filter can contain a number of pores larger than the nominal rating, which has the potential to allow passage of microorganisms. The probability of such passage is considered to increase as the number of organisms (bioburden) in the material to be filtered increases. A challenge concentration of at least 107 organisms per cm2 of effective filtration area of B. diminuta should generally be used. A commercial lot's actual influent bioburden should not include microorganisms of a size and/or concentration that would present a challenge beyond that considered by the validation study (Refs. 10, 11, 12). Direct inoculation into the drug formulation provides an assessment of the effect of drug product on the filter matrix and on the challenge organism. However, directly inoculating B. diminuta into products with inherent bactericidal activity or into oil-based formulations can lead to erroneous conclusions. When sufficiently justified, the effects of the product formulation on the membrane's integrity can be assessed using an appropriate alternate method. For example, the drug product could be filtered in a manner in which the worst-case combination of process specifications and conditions are simulated. This step could be followed by filtration of the challenge organism for a significant period of time, under the same conditions, using an appropriately modified product (e.g., lacking an antimicrobial preservative or other antimicrobial component) as the vehicle. Any divergence from a simulation using the actual product and conditions of processing should be justified. Factors that can affect filter performance normally include (1) viscosity of the material to be filtered, (2) pH, (3) compatibility of the material or formulation components with the filter itself, (4) pressures, (5) flow rates, (6) maximum use time, (7) temperature, (8) osmolality, (9) and the effects of hydraulic shock. When designing the validation protocol, it is important to address the effect of the extremes of processing factors on the filter capability to produce sterile effluent. Filter validation should be conducted using the worst-case conditions, such as maximum filter use time and pressure (Ref. 12). Filter validation experiments, including microbial challenges, need not be conducted in the actual manufacturing areas. However, it is essential that laboratory experiments simulate actual production conditions. The specific type of filter used in commercial production should be evaluated in filter validation studies. When the more complex filter validation tests go beyond the capabilities of the filter user, tests are often conducted by outside laboratories or by filter manufacturers. However, it is the responsibility of the filter user to review the validation data on the efficacy of the filter in producing a sterile effluent. The data should be applicable to the user's products and conditions of use because filter performance may differ significantly for various conditions and products. After a filtration process is properly validated for a given product, process, and filter, it is important to ensure that identical filter replacements (membrane or cartridge) used in production runs will perform in the same manner. Sterilizing filters should be routinely discarded after processing of a single batch. Normally, integrity testing of the filter is performed prior to processing, after the filter apparatus has already been assembled and sterilized. It is important that integrity testing be conducted after filtration to detect any filter leaks or perforations that might have occurred during the filtration. Forward flow and bubble point tests, when appropriately employed, are two integrity tests that can be used. A production filter's integrity test specification should be consistent with data generated during filtration efficacy studies. We recommend you consider use of sterilizing-grade filters in series; this is a common practice. To maintain sterility, equipment surfaces that contact a sterilized drug product or sterilized container or closure surfaces must be sterile so as not to alter purity of the drug (211.63 and 211.113). Those surfaces that are in the vicinity of sterile product or container closures, but do not directly contact the product should also be rendered sterile where reasonable contamination potential exists. It is as important in aseptic processing to properly validate the processes used to sterilize such critical equipment as it is to validate processes used to sterilize the drug product and its container and closure. Moist heat and dry heat sterilization are most widely used and the primary processes discussed in this document. It should be noted that many of the heat sterilization principles discussed in this document are also applicable to other sterilization methods. Sterility of aseptic processing equipment should be maintained by batch-by-batch sterilization. Following sterilization of equipment, containers, or closures, transportation or assembly should be performed with adherence to strict aseptic methods in a manner that protects and sustains the product's sterile state. Validation studies should be conducted demonstrating the efficacy of the sterilization cycle. Requalification studies should also be performed on a periodic basis. For both the validation studies and routine production, use of a specified load configuration should be documented in the batch records. The insulating properties of unevacuated air prevent moist heat under pressure from penetrating or heating up materials and achieving the lethality associated with saturated steam. Consequently, for such processes, there is a far slower thermal energy transfer and rate of kill from the dry heat in insulated locations in the load. It is important to remove air from the autoclave chamber as part of a moist heat under pressure sterilization cycle. For the various methods of sterilization, special attention should be given to the nature or type of the materials to be sterilized and the placement of biological indicators within the sterilization load. D-value of the biological indicator can vary widely depending on the material to be sterilized. Potentially difficult to reach locations within the sterilizer load or equipment train (for SIP applications) should be evaluated in initial studies. For example, filter installations in piping can cause a substantial pressure differential across the filter, resulting in a significant temperature drop on the downstream side. Biological indicators should be placed at appropriate downstream locations of this equipment to determine if the drop in temperature affects the thermal input at these sites. Requalification and/or revalidation should continue to focus on the load areas identified as most difficult to penetrate or heat (e.g., worst-case locations of tightly wrapped or densely packed supplies, securely fastened load articles, lengthy tubing, the sterile filter apparatus, hydrophobic filters, stopper load). The formal program providing for regular revalidation should consider the age of the sterilizer and its past performance. Change control procedures should adequately address issues such as a load configuration change or a modification of the sterilizer. a. Qualification: Empty Chamber Temperature distribution studies evaluate numerous locations throughout an empty sterilizing unit (e.g., steam autoclave, dry heat oven) or equipment train (e.g., large tanks, immobile piping). It is important that these studies assess temperature uniformity at various locations throughout the sterilizer to identify potential cold spots where there can be insufficient heat to attain sterility. These heat uniformity or temperature mapping studies should be conducted by placing calibrated temperature measurement devices in numerous locations throughout the chamber. b. Validation: Loaded Chamber Heat penetration studies should be performed using the established sterilizer load(s). Validation of the sterilization process with a loaded chamber demonstrates the effects of loading on thermal input to the items being sterilized, and may identify cold spots where there is insufficient heat to attain sterility. The placement of biological indicators (BI) at numerous positions in the load, including the most difficult to sterilize places, is a direct means of demonstrating the efficacy of any sterilization procedure. In general, the thermocouple (TC) is placed adjacent to the BI so as to assess the correlation between microbial lethality and thermal input. When determining which articles are most difficult to sterilize, special attention should be given to the sterilization of filters. Ultimately, cycle specifications for such sterilization methods are based on the delivery of adequate thermal input to the slowest to heat locations. A sterility assurance level of 10-6 or better should be demonstrated for a sterilization process. For more information, please also refer to the FDA guidance entitled Guideline for the Submission of Documentation for Sterilization Process Validation in Applications for Human and Veterinary Drug Products. For both validation and routine process control, the reliability of the data generated by sterilization cycle monitoring devices should be considered to be of the utmost importance. Devices that measure cycle parameters should be routinely calibrated. Written procedures should be established to ensure that these devices are maintained in a calibrated state. For example: · Temperature monitoring devices for heat sterilization should be calibrated at suitable intervals, as well as before and after validation runs. · Devices used to monitor dwell time in the sterilizer should be periodically calibrated. · The microbial count and D-value of a biological indicator should be confirmed before a validation study. · Bacterial endotoxin challenges should be appropriately prepared and measured by the laboratory. · Instruments used to determine the purity of steam should be calibrated as appropriate. · For dry heat depyrogenation tunnels, devices (e.g. sensors and transmitters) used to measure belt speed should be routinely calibrated. To ensure robust process control, sterilizing equipment should be properly designed with attention to features such as accessibility to sterilant, piping slope, and proper condensate removal (as applicable). Equipment control should be ensured through placement of measuring devices at those risk-based control points that are most likely to rapidly detect unexpected process variability. Where manual manipulations of valves are required for sterilizer operations, these steps should be documented in manufacturing procedures. Sterilizing equipment should be properly maintained to allow for consistently satisfactory function. Evaluation of sterilizer performance attributes such as equilibrium (come up) time studies should be helpful in assessing if the unit continues to operate properly.
In aseptic processing, one of the most important laboratory controls is the establishment of an environmental monitoring program. This monitoring provides meaningful information on the quality of the aseptic processing environment (when a given batch is being manufactured) as well as environmental trends of the manufacturing area. An adequate program identifies potential routes of contamination, allowing for implementation of corrections before product contamination occurs (211.42 and 211.113). Evaluating the quality of air and surfaces in the cleanroom environment should start with a well-defined written program and scientifically sound methods. The monitoring program should cover all production shifts and include air, floors, walls, and equipment surfaces, including the critical surfaces that come in contact with the product, container, and closures. Written procedures should include a list of locations to be sampled. Sample timing, frequency, and location should be carefully selected based upon their relationship to the operation performed. Samples should be taken throughout the aseptic processing facility (e.g., aseptic corridors, gowning rooms) using scientifically sound sampling procedures. Sampling sizes should be sufficient to optimize detection of environmental contaminants at levels that might be expected in a given clean area. Locations posing the most microbiological risk to the product are a critical part of the program. It is especially important to monitor the microbiological quality of the aseptic processing clean area to determine whether or not aseptic conditions are maintained during filling and closing activities. Air and surface samples should be taken at the actual working site and at locations where significant activity or product exposure occurs during production. Critical surfaces that come in contact with the sterile product should be sterile. When identifying critical sites to be sampled, consideration should be given to the points of contamination risk in a process, including factors such as difficulty of setup, length of processing time, impact of interventions. Critical surface sampling should be performed at the conclusion of the aseptic processing operation to avoid direct contact with sterile surfaces during processing. Detection of microbial contamination on a c |