Both are devices that provide a physical and aerodynamic (air overpressure) barrier between the external clean room environment and a work process.
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.
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.
The "negative pressure isolator," and has become less common and desirable, but is superior to the traditional biosafety cabinet which is vulnerable to contamination and can expose the worker to toxicological hazards if not operated properly.
In addition to Isolators, there are also extensive barriers that provide sub-isolation protection, but have a very good track record of reducing hazards to sterile drugs during processing when they are designed and operated properly.
In particular, a RABS that operates only in closed-door mode after the equipment setup and sporadic disinfection is performed, is commonly used now and provides substantial risk mitigation.
In the mid-1980s, after the industry had already begun to employ isolators, RABS units became an alternative to separating people from the process.
However, in some notable cases, gloveboxes used for aseptic processing have provided no more sterile product protection than the traditional laminar air flow hood (LAF) design of the 1960s.
However, if gloveboxes are very meticulously designed, thoroughly disinfected (e.g., using sporocides) and carefully operated by well-trained aseptic processing personnel to prevent introduction of microbial contamination, it is possible to obtain some degree of increased sterile product protection versus the simple traditional LAF hood.