ABSTRACT
Introduction With the majority of pharmaceutical products, the closure is an integral part of the pack, hence the word 'pack' covers both the container and the closure system. The latter may involve a unit dose or multidose where an included feature (e.g. heat seal, weld, peelable seal) or a separate feature (e.g. screw cap, lever lid) defines how the system functions. Because in most circumstances the pack is only as effective as the closure employed, a successful marriage between container and closure is essential to the product shelf life and its acceptance during use. In some instances a closure may serve a relatively simple function, i.e. act as a dust cover; at the other extreme it has to be hermetic, i.e. it permits no exchange between the product and the external atmosphere. This differs from a sterile closure system which retains sterility, i.e. prevents contamination from micro-organisms but may permit exchange by permeation of gases, moisture, etc. Sixty years ago there were relatively few closure systems, whereas today there are literally thousands. Closures and closure systems have as a result become both more sophisticated and more complex. This is particularly true when the closure assists in the administration of the product and/or where it incorporates special features to improve safety and security (tamper-evidence, tamper-resistance, child-resistance, etc.). This broadening role for closures and closure systems must cover the full life of the product (storage, transportation, display and use).
