Notes on USP31-NF26 <1116 - Microbiological Evaluation of Cleanrooms and Other Controlled Environments>

Modified 20181212 – minor typos corrected. minor updates.

The USP is the United State’s Pharmacopeia.  If you are selling pharmaceuticals in the USA, you need to follow the USP and are subject to FDA regulation.  For the layperson, a pharmacopeia is an official publication containing a list of medicinal drugs with their effects and directions for their manufacturing, testing and use.

I last reviewed USP 1116 in 2009 when it was version USP31–NF26.

Where one does not have direct access to the USP (it is behind a pay wall),  there are plenty of sites that review changes and publish their considered opinions.  The USP itself publishes Revision Bulletins, IRA’s (public comment documents showing proposed changes) and Errata.  From these one can build up a fairly accurate picture of the USP.

The latest iteration is USP 41–NF 36 — this became official on May 1, 2018.  The last version I managed to get my hands on was USP36 NF31.  What follows is my original review.

Notes on USP <1116> – microbiological evaluation of cleanrooms and other controlled environments

What follows are the most important tidbit’s extracts from USP <1116>.

The purpose of this informational chapter is to review the various issues that relate to aseptic processing of bulk drug substances, dosage forms and in certain cases, medical devices; and to the establishment, maintenance, and control of the microbiological quality of controlled environments.

There are alternative methods to access and control the microbiological status of controlled environments for aseptic production.

The improper application of microbiological sampling and analysis may cause significant variability and the potential for inadvertent contamination.  Sampling media and devices, and methods indicated in this chapter, are not specification but only informational.

Because aseptic processing relies on the exclusion of microorganisms from the process stream and the prevention of microorganisms from entering open containers during filling, product bioburden as well as microbial bioburden of the manufacturing environment are important factors relating to the level of sterility assurance of these products.

Establishment of Clean room Classifications

The design and construction of clean rooms and controlled environments are covered ion Federal Standard 209E.  The pharmaceutical industry (microbioligcal aspects of) has a greater concern for viable particles rather than total particulates specified in the standard.  A definite concern for counts of total particulates in injectable products exists in the pharmaceutical industry – see Particulate Matter in Injections <788>.

Clean rooms are maintained under a state of operational control on the basis of dynamic (operational) data.

Importance of a Microbiological Evaluation Program for Controlled Environments

Monitoring the environment for nonviable particulates and microorganisms is an important control function because they are both important in achieving product compedial requirements for Particulate Matter and Sterility under Injections <1>.

Microbial monitoring should assess effectiveness of cleaning and sanitation and personnel that could have an impact on the bioburden of the environment.  Microbial monitoring should provide sufficient information to ascertain that the controlled environment is operating within an adequate state of control.

The environment should be sampled during normal operations and should occur when materials are in the area, processing activities are ongoing and a full compliment of operating personnel is on site.

Microbial monitoring should include microbial content of room air, compressor air that enters the critical area, surfaces, equipment, sanitation containers, floors, wall and personnel garments.  The objective of the microbial monitoring program is to obtain representative estimates of the bioburden of the environment.

When data are compiled and analysed, any trends should be evaluated by trained personnel.  Review environmental results on the basis of recommended and specified frequency, also review results over extended periods to determine whether trends are present.

Periodic reports or summaries should be issued to alert the responsible manager.

When the specified microbial level is exceeded, documentation review and investigation should occur.

Investigation should include a review of the area maintenance documentation, sanitization documentation; inherent physical or operational parameters, such as changes in environmental temperature and relative humidity; and the training status of personnel involved.  Following the investigation, actions taken may include: training, additional sampling, additional sanitization, an evaluation of the SOP’s and revalidation of them.

Any investigation and the rationale for the course of action should be documented and included as part of the overall quality management system (QMS).

Proper testing and optimisation of the physical characteristics of the clean room or controlled environment is essential prior to completion of the validation of the microbiological monitoring program.

Training of Personnel

Aseptically processed products require rigorous discipline and strict supervision of personnel.

Monitoring of personnel should be conducted before or after working in the processing area.  Monitoring post is worse case and is recommended.

Management of the facility must assure all personnel are well versed in relevant microbiological principles.  Understanding of regulatory compliance policies and each individuals responsibilities with respect to good manufacturing practices should be an integral part of the training program.

The major source of microbial contamination of controlled environment is the personnel.  Only healthy individuals should be permitted access to controlled environments.

The control of microbial contamination associated with personnel is one of the most important elements of the environmental control program.
The environmental monitoring program will not be able to detect all events in aseptic processing that could compromise the microbiological quality of the environment so aseptic process simulation studies (formerly called sterile media media fill trials) are necessary.

Critical Factors Involved in the Design and Implementation of a Microbiological Environmental Control Program

Environmental control programs should be capable of detecting adverse drift in microbiological conditions in a timely manner

General media = Soybean Casein Digest

General mycological media = Sabourand’s, Modified Sab or Inhibitory Mould Agar.

Testing for obligatory anaerobes is not performed routinely.

Typically, incubation temperatures in the 22.5±2.5° and 32.5±2.5° ranges have been used with an incubation time of 72 and 48 hours, respectively.  Sterilisation process used to prepare growth media should be validated, media should be examined for sterility and growth promotion as indicated.  In addition, for the Growth Promotion test, representative microflora isolated from the controlled environment may also be used to test media.   Media must be able to support growth when inoculated with <100CFU of the challenge organisms.

The methods used for identification of isolates should be verified using indicator microorganisms (see Microbial Limits <61>).

Establishment of Sampling Plan and Sites

Air and surfaces in contact with a product or sensitive surfaces of container closure systems should be considered critical areas requiring more monitoring than non product contact areas.

As manual interventions during operations increase, the relative importance of environmental monitoring program increases.

The sampling plans should be dynamic with monitoring frequencies and sample plan locations adjusted based on trending performance.  It is appropriate to increase or decrease sampling based on this performance.

Establishment Of Microbiological Alert and Action Levels in controlled Environments

An Alert level shows a potential drift from normal operating conditions.

An Action level requires immediate follow-up and, if necessary, corrective action.

Microbial Considerations and Action Levels for Controlled Environments

When swabbing is used in sampling, the area covered should be greater than or equal to 24cm2 but no larger than 30cm2.  A sterile teplate is recommended.

Methodology and Instrumentation for Quantitation of Viable Airborne Microorganisms

Where the microbial level in the air of a controlled environment is expected to contain not more than three CFU per cubic meter, several cubic meters of air should be tested if results are to be assigned a reasonable level of precision and accuracy.

Methodology and Equipment for Sampling of Surfaces for Quantitation of Viable Microbial Contaminants in controlled Environments

To minimise disruptions to critical operations, surface sampling is performed at the conclusion of operations. Surface monitoring is generally performed on areas that come in contact with the product and on areas adjacent to those contact areas.

The area to be swabbed is defined using a sterile template of appropriate size.

Culture Media and Diluents Used for Sampling or Quantitation of Microorganisms

Alternative media to the ones in the regs can be used provided that they are validated for the purpose intended.

Identification of Microbial isolates from the Environmental Control Program

Identification of isolates from critical areas immediate to these critical areas should take precedence over identification of microorganisms from non critical areas.

Operational Evaluation of the Microbiological Status of Aseptically Filled Products in Clean Rooms and Other Controlled Environments

Issues in the development of an aseptic process simulation program that should be considered are the following: media-fill procedures, media selection, fill volume, incubation, time and temperature, inspection of filled units, documentation, interpretation of results and possible corrective actions required.

During the conduct of an aseptic process simulation fill, various pre-documented interventions that are known to occur during actual product runs should be planned.  This includes routine and ad hoc interventions.

Aseptic process simulation fill runs done to cover all production shift for line/product/container combinations.

Since the most critical source of contamination in the clean room is the personnel, visual documentation that can be helpful in correlating production activities to contamination events during aspeptic process simulations is encouraged.  The widespread use of isolator systems for sterility testing has demonstrated that elimination of personnel does reduce contamination in aseptic handling.

 An Overview of the Emerging Technologies for Advanced Aseptic Processing

Experience with isolators indicates that under normal operations pinhole leaks or tears in gloves represent the major potential for microbiological contamination; therefore, frequent testing of the gloves for integrity and surface monitoring of the gloves is essential.

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