The weakest link? Assessing isolator glove integrity failures

Abstract

For several decades isolators, as separative devices, have been commonplace in pharmaceutical and healthcare products manufacturing. Although isolators presented a significant step forward on the contamination control continuum, isolators, if not appropriately operated, can be vulnerable to contamination ingress. The primary mechanism for ingress is through air leakage and with the different points across the overall structure that are potentially vulnerable it is gloves that are the most leak-prone aspect (1). The gloves (or sometimes gauntlets, when in the form of a one-piece sleeve and glove) of an isolator are a necessary function of most isolators given they are the primary way through which humans interact with the environment inside (EU GMP Grade A / ISO 14644 class 5). As the PIC/S guidance states, Grade A can only be maintained when accessed through glove stations: “A Grade A internal environment is created, and manipulations are carried out through glove ports”. Given the availability of some gloveless isolators that rely upon robotics, this statement is a little out of date, however it makes the point that if personnel are present in an environment nominally called ‘Grade A’ then this environment ceases to be ‘Grade A’.