Application of the ‘dual sorption’ model to drug transport through skin

Abstract

The dual sorption theory has been extended to the transport of drug molecules through human skin in vitro. By assuming that sorption of drug molecules occurs by both dissolution and binding of drug to immobile sites in the skin, the experimental sorption isotherm can be predicted, and the disparity between steady state and time lag diffusivities can be reconciled. Furthermore, the dual sorption model has been used to develop techniques for controlling these sorption transport processes in order to rapidly achieve predictable transdermal drug delivery in vivo.

The Role of Corneocytes in Skin Transport Revised—A Combined Computational and Experimental Approach

“…It remains to be analysed whether the weakly acidic corneocyte pH could facilitate the corneocyte solubility of bases and thus mediate keratin access of lipophilic bases. This could provide the explanation for the significant concentration dependence of K SC,dry/don of scopolamine (47) although this may also have been a consequence of binding to the cpe.…”

“…Chandrasekaran et al transferred the concept to the interaction with human epidermal membranes and SC using the example of scopolamine (47). They described the process as a combination of dissolution creating mobile, freely diffusible molecules and adsorption producing non-mobile molecules that cannot contribute to the diffusion process (47). Between mobile and non-mobile species a rapid exchange compared to the diffusion time-scale and a local equilibrium is assumed.…”

“…This concept has first been introduced for the adsorption of gases to glassy polymers as the "dual sorption"-theory but may be ubiquitously applied to processes with concurrent mobile and fixed species of the same compound irrespective of the mechanism of immobilization (46). Chandrasekaran et al transferred the concept to the interaction with human epidermal membranes and SC using the example of scopolamine (47). They described the process as a combination of dissolution creating mobile, freely diffusible molecules and adsorption producing non-mobile molecules that cannot contribute to the diffusion process (47).…”

Isolated human and animal stratum corneum as a partial model for the 15 steps of percutaneous absorption: emphasizing decontamination, part II

“…Because theophylline partitions equally into the skin layers, the retention could be secondary to its binding to the protein domain. The data presented here verify earlier observations (Bronaugh & Congdon, ; Chandrasekaran et al ., ; Idson, ).…”

Transdermal delivery of peptide and protein drugs: An overview

“…Many drugs display a strong chemical bond or van der Waals attraction to components in the skin. As a result the drug becomes bound, perhaps strongly enough to form a drug depot, thereby reducing its permeation rate (Chandrasekaran et al, 1980;Barry, 1986). In fact, peptides and proteins have been found to become reversibly bound while permeating through excised skin (Wearley et al, 1990;Banga and Chien, 1993;Hoogstraate et al, 1994;Delgado-Charro and Guy, 1994;Thysman et al, 1994).…”