Effect of filtration by activated charcoal on the toxicological activity of cigarette mainstream smoke from experimental cigarettes

Abstract

Activated charcoal (AC) filtration reportedly decreases the yields of smoke vapor phase constituents including some identified as human carcinogens and respiratory irritants. Non-clinical studies including chemical smoke analysis, in vitro cytotoxicity and mutagenicity (bacterial and mammalian cells), and in vivo subchronic rat inhalation studies were carried out using machine smoking at ISO conditions with lit-end research cigarettes containing AC filters. The objective was to assess whether AC filter technology would alter the established toxicity profile of mainstream smoke by increasing or decreasing any known toxicological properties, or elicit new ones. The reduced yield of vapor phase irritants from AC filter cigarettes correlated with markedly decreased in vitro cytotoxicity and in vivo morphology of the nose and lower respiratory tract. Increased yields of particulate phase constituents (e.g. polycyclic aromatic hydrocarbons) in AC filtered smoke were noted in comparison to controls in some studies. The in vitro bacterial mutagenicity of AC filtered smoke particulate preparations was occasionally increased over control levels. Laryngeal epithelial thickness was increased in some rats inhaling AC filtered smoke in comparison to controls, an effect perhaps related to higher inspiratory flow. When tested under more intense Massachusetts Department of Public Health smoking conditions, AC filter associated reductions in vapor phase constituent yields were smaller than those seen with ISO conditions, but the effect on in vitro cytotoxicity remained.

Toxicological assessment of kretek cigarettes part 5: Mechanistic investigations, inhalation toxicity

“…1). There was less impact on body weight development in the female rats as has also been observed in previous inhalation studies of MS (Gaworski et al, 2009). The mean food consumption relative to body weight for all smoke exposed groups was comparable to the sham group for both sexes.…”

The use of charcoal in modified cigarette filters for mainstream smoke carbonyl reduction

“…Selective filtration of MSS has been achieved to differing degrees of effectiveness with a range of filtration media, including activated carbon, or charcoal (Coggins and Gaworski, 2008; Polzin et al, 2008), synthetic polymer carbon (Nother et al, 2016), ion-exchange resins (Branton et al, 2011b), and polymer-based adsorbents (Dittrich et al, 2014; McAdam et al, 2012). Toxicological assays and human biomarker studies demonstrate the efficacy of selective filtration in filtered cigarettes with selective filtration media versus filtered cigarettes alone (Bombick et al, 1997; Gaworski et al, 2009; Hoffmann et al, 1976; Laugesen and Fowles, 2005; Roemer et al, 2004; Thayer and Kensler, 1964). …”

“…Charcoal is characterized by high specific surface area and porosity, facilitating the adsorption of volatile and semi-volatile chemicals from MSS, including aldehydes, aliphatic amines, and monocyclic aromatic compounds (Branton et al, 2009; Gaworski et al, 2009; General, 1981; Pauly et al, 1997). Despite limited U.S. market share (Hoffmann et al, 2001), cigarette manufacturers have experimented with charcoal filtration in prototype cigarettes and have included charcoal in marketed cigarette filters from the mid-1950s through today (Barton, 1964; Farr and Revere, 1958; Kensler and Battista, 1963; Mait and Wickham, 1990).…”

“…Synthetic charcoal-filtration reduced mouth-level exposure of toxicants versus non-charcoal filtered cigarettes (Nother et al, 2016). Decreases in genotoxicity and cytotoxicity have been demonstrated with charcoal filtration (Bombick et al, 1997; Gaworski et al, 2009; Thayer and Kensler, 1964), and decreased levels of human biomarkers of harm were observed when humans switched to charcoal-filtered cigarettes (Sarkar et al, 2008). Additionally, charcoal-filtered MSS resulted in decreased MSS bioactivity compared to non-charcoal filtered cigarettes (Hoffmann et al, 2001), and evidence suggests decreased cancer mortality rates with the use of charcoal filters versus conventional filters (Coggins and Gaworski, 2008; Muscat et al, 2005).…”

Use of Classical Adsorption Theory to Understand the Dynamic Filtration of Volatile Toxicants in Cigarette Smoke by Active Carbons

“…The subject continues to attract research interest ranging from material characterization (Sasaki et al 2008;), their effectiveness in reducing volatile toxicants (Laugesen andFowles 2005, 2006;Rees et al 2007;Polzin et al 2008;Hearn et al 2010) and potential biological effects (Bombick et al 1997;Coggins and Gaworski 2008;Gaworski et al 2009). …”