Introduction
This document will discuss the requirement for goggle use within Aseptic Processing Areas (APA) as well as products and processes that are available to assist sites in complying with established requirements. Suggested elements of a sterile goggle program are also considered.
This guidance provides background information forming the basis for the requirement for sterilized goggles and discusses goggle availability, sterilization compatibility, and program considerations.
Recommendations & Rationale
United States based APA sites first encountered regulatory concern from the Medicines and Healthcare products Regulatory Authority (MHRA) requiring the use of sterilized goggles within APA manufacturing operations for any aseptically manufactured product exported for use in Europe.
The FDA has supported the use of sterilized goggles as supported within its’ Guidance document “Guidance for Industry – Sterile Drug Products Produced by Aseptic Processing”, published in September 2004. This guidance indicates that gown articles worn within the aseptic processing area should be sterilized and further specifies goggles as part of this sterile ensemble.
FDA 483 citations have been issued to aseptic pharmaceutical sites where goggles have been sanitized with isopropyl alcohol prior to use as opposed to being sterilized.
As with every other article that comprises the sterile gown, it is interpreted that use of a newly sterilized pair of goggles would need to be donned with every gowning. As the human element is the greatest contamination contributor, the aseptic quality of the garments meant to act as the particulate barrier between human and environment must be maintained at the highest levels.
Goggles should be chosen, in part, based on their ability to contain particles shed by the wearer as well as not release any contaminating particles or fibers from the goggle itself. The need for goggles to be sterile within the APA is supported by the following principles. First and foremost, the criticality of the aseptic filling environment requires every other gown component to be sterile at the time of donning, including boots that touch the floor and are maintained well below line surfaces.
The proximity of the goggle area, being above the filling line, places the goggle surfaces in the air path upstream of objects at working height. These objects include tools and implements that may come into contact with critical line surfaces, as well as product or product components.
While it is relatively easy to understand the premise behind the requirement for goggle sterilization, meeting that requirement can be challenging.
Goggle Program -Points to Consider
Just as the use of sterilized APA gowning components requires a comprehensive program to monitor suppliers, materials of construction, sterilization validation, and use parameters, sterile goggle usage will have similar requirements including considerations due to the possible re-use of these items. Components of such a program are suggested below.
Disposable or Reusable Goggles
Goggles can be obtained sterile and ready-to-use as disposable or re-sterilizable models. Sources have been identified that can supply sterilized goggles to virtually any part of the world.
While disposable goggles may be more costly and generate excess waste, this practice eliminates the need for tracking the sterilization history of the goggles and verification or maintenance of a cleaning and re-sterilization program. At least two disposable models are available. These goggles are available triple wrapped, sterilized by ethylene oxide or gamma irradiation. Validation documentation of the sterilization of these goggles needs to be reviewed and is available from certified vendors.
Single use, pre-sterilized models are available starting at a nominal cost. Shipment outside of the US would add to this base cost which would be determined based on the location distance between the vendor and the final shipping site as well as overall volume.
Any vendor that supplies re-usable goggles will need to have complete validation data readily available for review to support the goggles throughout its’ lifecycle if the goggles are cleaned and re-sterilized by the supplier. In some cases complete validation packages are available that document a sterilization compatibility program for their product, regardless of sterilization location, within specified sterilization parameters. Goggles sterilized by ethylene oxide (ETO) must also have safety data available that verifies any remaining residual levels of ETO present in the goggles post sterilization is below established exposure limits for each sterilization cycle.
Re usable goggles are more cost effective over the long-term and numerous studies have been completed by goggle suppliers, evaluating the effects of repeat sterilization on goggle components. If re-usable goggles are maintained at a GMP facility, the cleaning procedure of the goggles, in addition to the re-sterilization procedure effectiveness, is critical for verifying removal of non-viable particulates that can accumulate with repeated usage and may impact sterilization. While sterilization of the goggles is the focus of this bulletin, cleaning of the goggles is a potentially critical component for any re-usable goggle due to the direct ability to properly re-sterilize (e.g. ETO). FDA 483 citations have also been issued for lack of goggle cleaning programs when used in the APA.
Re-Usable Goggle Considerations
- Include a use number tracking mechanism based on a validated and documented ability of the goggles to perform as specified,
- Be able to maintain the safety of the operators wearing them.
Tracking in the gowning industry is often accomplished through the use of bar coding. For instance, one vendor has accomplished the tasks of tracking and particle containment by placing a bar-code on the low particulate material used to cover the elastic strap of the goggle. The development of a tracking program is necessary if goggles are to be re-sterilized as goggle materials deteriorate during the sterilization process. The effects differ based on sterilization technology as well as the materials of construction for each specific goggle type. Goggles have been identified that are compatible with steam, ETO, and gamma irradiation sterilization. When resterilization is performed by a vendor, that vendor maintains the responsibility of tracking.
With the increasing expectations for use of goggles that are sterile, numerous suppliers are in the process of developing goggles that can withstand higher numbers of sterilization cycles for re-use before final disposal. Some models have the ability to change the lenses.
Definition of Sterilization – Risk Analysis
While ethylene oxide, gamma irradiation and steam sterilization are the most documented and utilized forms of sterilization, other means of surface sterilization have been successfully documented and used in house for surface sterilization.
Vapour phase hydrogen peroxide (VHP), hydrogen peroxide/paracetic acid, and other surface sterilants may potentially produce a goggle that meets sterility assurance requirements. These techniques have been shown to be capable of surface sterilization for other applications that have not required a typical terminal sterilization sterility assurance level (SAL). As these methods are not first line sterilants for the purpose of sterilizing goggles, studies would need to be performed and documented on an individual basis to ensure all materials are compatible with the sterilization technique chosen for proper functionality within the APA and to show that all surfaces are sterilized. These methods should have formal validation and documentation.
Conclusion
Few goggle materials can withstand autoclave conditions. Gamma irradiation causes a discoloration effect and increased brittleness on the goggles after numerous sterilization cycles, depending on dosage and exposure. Ethylene oxide leaves residuals that, when not properly de-gassed, can have undesirable irritation effects on the user. The ETO residuals build with each additional sterilization cycle, even with proper degas, and the goggles have a defined use life cycle. Monitoring the ETO off gassing is required after each sterilization cycle.
The table included in this document specifies a sampling of various goggle types, manufacturers or distributors and capability for re-sterilization. This table will be updated as significantly new information on goggles becomes available.