RESPONSE TO DR. RICHTER'S LETTER
To the Editor,
We thank Dr. Richter for pointing out the recently reported NNK solubility data in saline (Azzi et al., Citation2006). At the time our manuscript was prepared and submitted, this reference was unavailable to us.
However, we would like to mention that the definition of the limit at which a substance is considered “insoluble” depends upon the context of use (Bennington, Citation1984). The aim of our article (Feng et al., Citation2007) was to demonstrate the utility of a new methodology for estimating the retention of selected mainstream smoke constituents in the respiratory tract of smokers during cigarette smoking. We considered relatively different water solubility (i.e., nicotine > NNN > NNK under human physiological pH, calculated using ACD/Solubility DB software) as one of the possible factors that may influence the respiratory retention. Therefore, our interest with regard to solubility was relative rather than absolute values. The new data reported by Azzi et al. (Citation2006) should have no impact on the results and conclusions reported in our article.
Sincerely,
REFERENCES
- Azzi C., Zhang J., Purdon C. H., Chapman J. M., Nitcheva D., Hebert J. R., Smith E. W. Permeation and reservoir formation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and benzo[a]pyrene (B[a]P) across porcine esophageal tissue in the presence of ethanol and menthol. Carcinogenesis 2006; 27: 137–145
- Bennington J. L. Saunders dictionary and encyclopedia of laboratory medicine and technology. W.B. Saunders, Philadelphia 1984; 811
- Feng S., Plunkett S. E., Lam K., Kapur S., Muhammad R., Jin Y., Zimmermann M., Mendes P., Kinser R., Roethig H. J. A new method for estimating the retention of selected smoke constituents in the respiratory tract of smokers during cigarette smoking. Inhal. Toxicol. 2007; 19: 169–179