Cigarette Mainstream Smoke: The Evolution of Methods and Devices for Generation, Exposure and Collection

Abstract

SUMMARY The objective of this review is to support tobacco scientists when evaluating information published on smoking machines, and on cigarette mainstream smoke (in vivo and in vitro) exposure systems and collection devices. The intriguing development of smoking machines (mainly for cigarettes) is followed for more than 170 years - from the first simple set-ups in the 1840s to the sophisticated and fully automated analytical smoking machines available today. Systems for the large-scale production of smoke (condensate) for preparative work are equally considered. The standardization of machine smoking methods and test pieces has solved several technical problems and produced sensible rules but, at the same time, given rise to new controversies like the compatibility of artificial and human smoking, and the implementation of more intense machine smoking regimes. Adequate space is allotted for the discussion of configurations for in vivo smoke exposure of rodent and non-rodent species and the machines generating the required smoke (condensate). Covered as well is the field of in vitro toxicity testing, including the increasingly informative new techniques of air-liquid interface exposure, which are becoming more and more refined with the use of organotypic cultures and genetic analyses. The review is completed by the examination of the considerable variety of mainstream smoke collection devices (filters and traps) developed over time - some for very specific purposes - and refers to the perpetual problem of artifact formation by aging.