barrier isolator barrier isolator barrier isolator is a general term that includes two types of devices: isolators and restricted access barriers (rabs). both are devices that provide a physical and aerodynamic (air overpressure) barrier between the external clean room environment and a work process. the isolator design is the more dependable of the two barrier design choices, as it prevents contamination hazards by achieving a more comprehensive separation of the processing environment from the surrounding facility. nonetheless, both isolator and rabs designs are contemporary approaches developed over the last 35 years and a great advancement over designs of the 1950s-70s that were far more prone to microbial contamination problems. barrier and isolator designs are used throughout the industries, from sterile injectable drug filling to cytotoxic sterile drug compounding to electronics manufacturing to orange juice filling. pharmaceutical industry and pharmacy compounding isolators are used for maintaining sterility of a drug, and that is the focus of this article. this type of strict design and control is important when producing sterile medicines because consumers receiving injections, surgical irrigation fluid, or other "parenterally"-administered drugs are often highly vulnerable to infection. as a result, contaminated drugs have caused grave (e.g., permanent injury, death) consequences for the consumer. the sterility of other dosage forms, such as ophthalmic, is similarly important, as blindness or partial loss of vision has occurred due to intrinsically contaminated eye medications. isolators are routinely found within the pharmaceutical industry and are widely used in europe (and increasingly in the us) for pharmacy aseptic compounding applications.