Recommended Practices in Isolator/Glovebox Cleaning

An isolator/glovebox is a miniature version of a cleanroom and is often certified to ISO cleanroom classifications. Therefore, the cleaning methods for cleanroom environments as described in IEST-RP-CC018.4, Cleanroom Housekeeping: Operating and Monitoring Procedures and
International Standard ISO 14644-5, Cleanrooms and associated controlled environments – Part 5: Operations may be used to clean an isolator/glovebox.

During development and prior to implementation of any cleaning protocol, it is recommended that this cleaning protocol be reviewed and approved by both safety and quality managers. All cleaning agents used should be product compatible, process compatible, compatible with isolator/glovebox construction materials, and environmentally compatible.

All cleaning should be carried out both before and after every manufacturing, preparation, or dispensing session, as well as in between activities that may result in cross contamination.

The recommended cleaning sequence for both a cleanroom and an isolator/glovebox is:

• Clean from the cleanest area to the dirtiest area
• Vertical airflow—top to bottom
• Horizontal airflow—wall to return

Just as in cleaning a cleanroom, the ceiling or the top of the isolator/glovebox is cleaned first, taking care not to compromise the HEPA or ULPA filters, then the back wall of the isolator/glovebox, the right and left sides, the inside front panel, and the floor of the isolator/glovebox. The recommended validated cleaning methods are:

• When cleaning the sides of the isolator/glovebox, overlapping, straight, pull and lift strokes are performed cleaning either left to right or right to left or top to bottom (see Figure 1). Begin cleaning at the rear of the isolator/glovebox and work towards the front. When cleaning the floor of the isolator/glovebox, one can wipe from the rear of the box to the front in a modified figure-8 pattern. (See Figure 2).
• Inspect the wiper surface after each pass. If there is no visible contamination, you may use the same surface of the wiper up to four consecutive passes.
• Use a quarter-folded wiper so that gloves are not contaminated and a clean surface of the wiper is used for each pass. The 12” X 12” wiper is folded into four quarters to obtain eight clean surface areas.
• There are commercially available cleaning tools such as wands that will hold a wiper and/or pad. Use this isolator cleaning tool for areas hard to reach. Change the wiper or cover after each isolator surface.
• Use polyester swabs for crevices and other hard to clean areas. Change swabs after each use.

An example of a generic standard operating procedure for cleaning an isolator/glovebox is listed below.

1. Begin by wearing all the appropriate PPE (personal protective equipment). This should be determined by the safety manager.
2. Be certain the system is in operation.
3. Put on approved disposable gloves. Wipe the outside of the isolator/glovebox front and sides with approved cleaning materials and wiper. NOTE: Toss soiled wipers into a waste chute or appropriate waste disposal device after each step or when the clean surface of wiper is soiled.
4. Wipe down gloved hands and the containers of cleaning products to be used with wipers pre-saturated with sterile 70% Isopropyl Alcohol (or approved cleaner) and place products in the isolator/glovebox. Check that all tools used to clean the isolator/glovebox are wiped clean before cleaning interior. Remove the disposable gloves.
5. Place hands into the integrated gloves of the isolator/glovebox. Mist and wipe down integrated gloves with new clean wiper. A new surface of the wiper is used to wipe each individual surface.
6. Mist and wipe the inside of the isolator/glovebox in the same order as cleaning a cleanroom as mentioned above. Care must be taken when cleaning the top of the isolator/glovebox so as to not destroy the HEPA filter. Do not allow any liquid to contaminate the filter face. Any section and/or corner that cannot be reached with integrated gloves can be cleaned using a commercially available isolator cleaning tool or other recommended device designed for the task.
7. Remove soiled wipers and waste chute or appropriate waste removal device using appropriate waste removal procedure.
8. Remove cleaning materials from isolator/glovebox.
9. Record all cleaning on Isolator Cleaning Documentation Checklist.

The above standard operating procedure may be used as a template that must be revised for your particular operation. More detailed information should be written into the SOP to direct all operators to perform the cleaning of the isolator/glovebox in a uniform, repeatable, and robust manner. Additional information that should be contained in the standard operating procedure is how to monitor the cleanliness of the isolator/glovebox, the alert and action specifications, and how to correct out of specification results.

Just as environmental monitoring of the cleanroom documents the efficacy of the cleaning of the cleanroom, an environmental monitoring program should be developed to monitor the removal of viable and non-viable particles inside the isolator/glovebox. The environmental monitoring test results should be recorded and trended. This will provide the documented evidence required to assure the cleaning method is robust and repeatable and the cleaning is effective.

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Jan Eudy is a Cleanroom/Contamination Control Consultant as well as a Fellow and Past President, Institute of Environmental Sciences and Technology. She is located in Carolina Beach, N.C. and can be reached at [email protected].

This article appeared in the January/February 2015 issue of Controlled Environments.