Lin R Y, Chen W Y, Liao C W
Department of Chemical Engineering, National Central University, Chung-Li, Taiwan, R.O.C.
J Control Release. 1998 Jan 2;50(1-3):51-9. doi: 10.1016/s0168-3659(97)00118-1.
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.
本研究采用由购买的角质层脂质组成的大单层囊泡，以研究氨基酸/二肽与角质层脂质囊泡的结合/分配情况。通过高效液相色谱法测定氨基酸/二肽在角质层脂质囊泡和乙酸盐缓冲液之间的分配系数。此外，通过等温滴定量热法直接测量结合/分配热，得出氨基酸/二肽与角质层脂质囊泡的结合/分配焓。根据结合/分配吉布斯自由能和结合/分配焓，氨基酸/二肽与角质层脂质囊泡的所有结合/分配均为吸热过程，这意味着是熵驱动的结合/分配。而且，平衡结合/分配结果表明，氨基酸/二肽的分配系数与透皮渗透率无关。这一发现表明，要么渗透剂与角质形成细胞之间脂质双层的相互作用可能不是决定性步骤，要么细胞旁路不是透皮渗透的主要途径。
