| Title: | Spectral Reflectance Measurement of Evaporating Chemical Films: Initial Results and Application to Skin Permeation |
| Author(s): | Frasch HF; Lee L; Barbero AM; |
| Address: | "Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26508. Electronic address: HFrasch@cdc.gov. Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26508" |
| DOI: | 10.1016/j.xphs.2018.04.020 |
| ISSN/ISBN: | 1520-6017 (Electronic) 0022-3549 (Linking) |
| Abstract: | "The present study has 2 aims. First, the method of spectral reflectance was used to measure evaporation rates of thin ( approximately 25-300 mum) films of neat liquid volatile organic chemicals exposed to a well-regulated wind speed u. Gas-phase evaporation mass transfer coefficient (k(evap)) measurements of 10 chemicals, 9 of which were measured at similar u, are predicted (slope of log-log data = 1.01; intercept = 0.08; R(2) = 0.996) by a previously proposed mass transfer correlation. For one chemical, isoamyl alcohol, the dependence of k(evap) on u(0.52) was measured, in support of the predicted exponent value of (1/2). Second, measured k(evap) of nicotine was used as an input in analytical models based on diffusion theory to estimate the absorbed fraction (F(abs)) of a small dose (5 muL/cm(2)) applied to human epidermis in vitro. The measured F(abs) was 0.062 +/- 0.023. Model-estimated values are 0.066 and 0.115. Spectral reflectance is a precise method of measuring k(evap) of liquid chemicals, and the data are well described by a simple gas-phase mass transfer coefficient. For nicotine under the single exposure condition measured herein, F(abs) is well-predicted from a theoretical model that requires knowledge of k(evap), maximal dermal flux, and membrane lag time" |
| Keywords: | "Administration, Cutaneous Diffusion Female Humans Models, Biological Nicotine/chemistry/pharmacokinetics Skin/*metabolism *Skin Absorption Volatile Organic Compounds/chemistry/*pharmacokinetics in vitro model(s) mathematical model(s) passive diffusion per;" |
| Notes: | "MedlineFrasch, H Frederick Lee, Larry Barbero, Ana M eng Research Support, U.S. Gov't, P.H.S. 2018/05/02 J Pharm Sci. 2018 Aug; 107(8):2251-2258. doi: 10.1016/j.xphs.2018.04.020. Epub 2018 Apr 27" |
