Case Study: Successful Decontamination of an Aseptic Fill Isolator Using Chlorine Dioxide Gas

Isolators are gas-tight enclosures typically used in either animal isolation or pharmaceutical production applications. The isolator acts as a small clean room to protect what is contained within it from any type of contaminant that exists in the normal environment. In any scenario of isolator use, the cleaning of the inside is periodically needed and can often present a challenge to the user and facility. In many applications, the isolator will be sprayed with a variety of cleaning compounds and then wiped down. While the spray and wipe is better than not cleaning at all, it will rarely result in creating a sterile environment within the isolator. The best method for creating a sterile isolator before or after use is by exposing it to a true gas, such as a chlorine dioxide (CD).

One pharmaceutical company tested a chlorine dioxide gas generator for its sporicidal activity on a prototype La Calhene aseptic fill isolator equipped with two half-suits. Twenty biological indicators were used as the microbial challenge for each test.  They were placed throughout the isolator on representative surfaces such as the exhaust vent, HEPA fan grill, and accumulator.  The biological indicators were either used in their original glassine envelopes or removed from the glassine envelope and transferred into Tyvek/film pouches. The variables of humidification time, CD concentration and CD exposure time were manipulated. Charging time to an exposure concentration of 5mg/L took approximately 9 minutes. Aeration time to safe exposure levels of 0.1ppm took less than an hour. Several exposure cycles were shown to be successful using biological indicator spore strips each having a population of 106 spores. Additionally, chlorine dioxide gas penetrated into dead-leg areas and hard to reach areas of the isolator, such as deep vents, half-suit armpits and beneath other structures. Chlorine dioxide has proven itself to be a practical and effective method for disinfecting isolators as demonstrated by the high-level spore reduction.

To read this company’s isolator decontamination study in full, click here. For more about this specific application, click here.