A mathematical model of the permeation kinetics of the membrane-coated fiber technique accounting for partition, diffiusion and boundary layer factors.
Xia-XR; Baynes-RE; Monteiro-Riviere-NA; Riviere-JE
Toxicologist 2003 Mar; 72(S-1):379
A mathematical model was developed to describe the permeation kinetics of the membrane-coated fiber (MCF) technique, which is used for in vitro assessment of dermal absorption of chemical mixtures. In addition to the basic percutaneous absorption factors, partition coefficient and membrane diffusivity, a boundary layer adjacent to the membrane was considered in the model. The cumulative amount permeated into the membrane was expressed as a function of permeation time in an exponential equation. The two constants introduced into the model, clearly defined with the physiochemical parameters of the system, can be obtained by regression of the experimental data sampled over a limited time. The partition and diffusion coefficients, as well as, the thickness of the boundary layer were calculated from the two constants. The mathematical model adequately described the permeation kinetics of the MCF technique. All of the theoretical predictions were supported by the experimental results. The measured partition coefficients were correlated well with the published octanol/water partition coefficient (R2=0.88). The thickness of the boundary layer was 5.2Jlm in a donor solution stirred at 400 rpm. The contribution of the boundary layer to the permeation kinetics is 2K times larger than that of the membrane, where K is the partition coefficient of a given compound. These results suggest that the permeation rate of a hydrophobic compound could be controlled by the boundary layer even though the diffusivity of the compound in the membrane is lower than that in the donor solution.
Mathematical-models; Diffusion-analysis; Kinetics; In-vitro-study; Models; Skin-exposure
Disease and Injury: Allergic and Irritant Dermatitis; Work Environment and Workforce: Mixed Exposures
The Toxicologist. Society of Toxicology 42nd Annual Meeting and ToxExpo, Cutting-Edge Science, Networking, New Perspectives, March 9-13, 2003, Salt Lake City, Utah
North Carolina State University, Raleigh, NC