Inhalation Toxicology, 2009; 21(12): 1040–1052 RESEARCH ARTICLE Chemical analysis of cigarette smoke particulate generated in the MSB-01 in vitro whole smoke exposure system Mariano J. Scian 1 , Michael J. Oldham 2 , John H. Miller 3 , David B. Kane 2 , Jeffery S. Edmiston 2 , and Willie J. McKinney 2 1 Rem X Speciality Staffing, c/o Altria Client Services, 2 Altria Client Services, Center for Research and Technology, Richmond, VA, USA, and 3 Philip Morris USA Research Center, Richmond, VA, USA Address for Correspondence: Jeffery S. Edmiston, Altria Client Services, Center for Research and Technology, 601 East Leigh Street, Richmond, VA 23219, USA. E-mail: Jeffery.S.Edmiston@altria.com (Received 10 October 2008; revised 22 December 2008; accepted 23 December 2008) Introduction Mainstream cigarette smoke (MS) is a dynamic two-phase aerosol consisting of a gas–vapor phase and a particulate phase containing over 4000 individual chemical constituents (Church & Pryor, 1985; Hoffmann & Wynder, 1986). Past in vitro investigations have typically used exposure methodol- ogies focused on either the gas–vapor or particulate phase, but not whole MS. ese methodologies include isolation of the particulate phase with a Cambridge filter pad, referred to as cigarette smoke condensate or total particulate matter (CSC or TPM), and cigarette smoke bubbled through a liq- uid medium, typically phosphate buffered saline (PBS) or cell culture media (Bombick et al., 1998a; Gebel & Muller, 2001; Kode et al., 2006; Muller & Gebel, 1994; Roemer et al., 2002). In the last few years, novel in vitro whole smoke exposure systems have been described in the literature (Aufderheide et al., 2003; Bombick et al., 1998b; Phillips et al., 2005; Ritter et al., 2004; Wolz et al., 2002). ese sys- tems expose cells directly to MS, thereby more closely simu- lating the events seen in the human respiratory tract. Recent work has focused on the importance of correctly translating human dosimetry into appropriate in vitro study exposures (Ewing et al., 2006; Phalen & Oldham, 2006; Phalen et al., 2006; Teeguarden et al., 2007). e importance of realistic site-specific doses for the result- ing observed in vitro toxicity has been shown for benzo(a) pyrene by Ewing et al. (2006). is motivated us to expand on our previous work (Scian et al., 2008) to characterize the Burghart Mimic Smoker-01 (MSB-01) whole smoke exposure system for in vitro MS exposure (Figure 1). e ISSN 0895-8378 print/ISSN 1091-7691 online © 2009 Informa UK Ltd DOI: 10.1080/08958370802712705 Abstract Cigarette mainstream smoke (MS) is a dynamic aerosol consisting of a gas–vapor phase and a particulate phase. In recent years, novel in vitro whole smoke exposure systems have been developed to expose cells directly to whole MS. One such system is the Burghart Mimic Smoker-01 (MSB-01). Our previous data using the MSB-01 indicated that a 50 ± 10% loss of particulate matter occurred prior to MS delivery into the exposure chamber. Additionally, a change in aerosol particle diameter was also measured, suggesting that the chemical composition of MS might be changing within the system. In this study, we have expanded on our previous work and com- pared the particulate phase chemical composition of undiluted and diluted MS generated by the instrument and that of the MS delivered into the exposure chamber. The average percent delivery of cigarette smoke condensate (CSC) detected for all the measured chemical constituents was 35 ± 13% for undiluted MS and 23 ± 8% for 1:1 diluted MS. The data also indicate that under our experimental conditions, incomplete mixing of the freshly gen- erated MS occurs during its dilution by the system. Taken together, the data presented here show that significant chemical changes occur between the generation of MS by the system and its delivery into the exposure chamber. This indicates that due to the dynamic nature of cigarette smoke, it is important to characterize the exposure conditions in order to gain the best insight and accurately correlate exposure with biological endpoints. Keywords: cigarette smoke condensate; in vitro; exposure; chemical analysis http://www.informahealthcare.com/iht Inhalation Toxicology Downloaded from informahealthcare.com by University of Virginia on 01/18/12 For personal use only.