Entropy-driven binding/partition of amino acids/dipeptides to stratum corneum lipid vesicles.
This study employed large unilamillar vesicles composed of purchased stratum corneum lipids to investigate the binding/partition of amino acids/dipeptides to stratum corneum lipid vesicles. The partition coefficients of amino acids/dipeptides between the stratum corneum lipid vesicles and the acetate buffer were determined by HPLC. In addition, the binding/partition enthalpy of amino acids/dipeptides with the stratum corneum lipid vesicles was derived by directly measuring the binding/partition heat with isothermal titration calorimetry. According to the binding/petition Gibbs free energy and the binding/partition enthalpy, all the binding/partition of amino acids/dipeptides with the stratum corneum lipid vesicles is endothermic, implying an entropy-driven binding/partition. Also, the equilibrium binding/partition results demonstrate that the partition coefficients of amino acids/dipeptides do not correlate with the transdermal permeability. This finding suggests that either the interaction between the penetrants and the lipid bilayer between corneocytes may not be a determining step or that the paracellular path is not a dominant route of transdermal penetration.
Department of Chemical Engineering, National Central University, Chung-Li, Taiwan, R.O.C.
R Y
RY
Lin
W Y
WY
Chen
C W
CW
Liao
D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism*; D004817:Epidermis / Q000378:metabolism*; D008051:Lipid Bilayers / Q000378:metabolism*; D012995:Solubility; D013816:Thermodynamics
D000596:Amino Acids; D004151:Dipeptides; D008051:Lipid Bilayers