Development of a quantitative method for assessment of dose in in vitro evaluations using a VITROCELL® VC10® smoke exposure system

The assessment of potential cytotoxicity or genotoxicity of combustible tobacco products has historically been performed using partitioned exposures (i.e. total particulate matter [TPM], gas vapor phase [GVP]) rather than whole smoke. The VITROCELL® VC10® smoke exposure system offers multiple platforms for air liquid interface (ALI) or air agar interface (AAI) exposure to mimic in vivo-like conditions for assessing the toxicological impact of whole smoke using in vitro assays (e.g. cytotoxicity, mutagenicity and DNA modifications). The aims of this study were to investigate dosimetry during whole smoke exposure in the VITROCELL® VC10® smoking robot using quartz crystal microbalances (QCMs) and to support the use of photometers for concurrent assessment of ‘dose’ during whole smoke exposures. QCM results showed consistent deposition across different exposure chambers, between dilution bars, experiments and modules. Higher levels of variation were noted at higher airflows (i.e., >8 L/min). Dosimetry assessed using photometers also showed a high level of consistency between experiments, with no notable impact on deposition on the QCM when the photometers were placed ‘in-line’ between the dilution bar and the exposure module. However, the use of photometers alone may be not be sufficient to estimate deposition; the predictability of the data-generated equation was poor. Further development of dosimetry methodology and information for use in validated in vitro biological test methods is needed to facilitate on-going aerosol-based research and relative assessment. •A dose-determining method was developed using the VITROCELL® VC10® system•Measured dose was consistent between exposure chambers and replicate experiments•Dose assessments were consistent using Quartz Crystal Microbalances (QCM) and photometers at lower airflows•At higher airflows, dose assessment at air-liquid-interface and air-agar-interface using photometers is recommended