Zhang I, Shung K K, Edwards D A
Department of Chemical Engineering, 204 Fenske Lab, PA 16802, USA.
J Pharm Sci. 1996 Dec;85(12):1312-6. doi: 10.1021/js9601142.
The sonophoretic transport rates of monomeric insulin and vasopressin across human skin in vitro in the presence of a 20 kHz ultrasound field are shown to differ substantially depending on whether molecules enter the skin from a saline solution or from a viscous ultrasonic coupling medium (specifically, a methyl cellulose hydrogel or viscous sol). Theoretically, the reduction in sonophoretic transport caused by the hydrogels can be explained by boundary layers that form within the hydrogel owing to the relatively rapid rate of molecular transport across the (ultrasonically) permeated stratum corneum as well as poor diffusive mass transfer between the skin and gel. The results of in vitro experiments performed with an ac current accompanying the ultrasound show that the mass-transfer barrier posed by the hydrogel can be eliminated for both vasopressin and insulin by suppressing the diffusive boundary layers, indicating that relatively high rates of sonophoretic molecular transport across human skin are achievable when hydrogels are used as the ultrasound coupling medium as long as method is used to induce molecular mixing within the gel.
在20 kHz超声场存在的情况下，单体胰岛素和加压素在体外透过人体皮肤的声致孔转运速率显示出显著差异，这取决于分子是从盐溶液还是从粘性超声耦合介质（具体而言，甲基纤维素水凝胶或粘性溶胶）进入皮肤。从理论上讲，水凝胶导致的声致孔转运减少可通过水凝胶内形成的边界层来解释，这是由于分子穿过（超声）渗透的角质层的相对快速速率以及皮肤与凝胶之间较差的扩散传质。伴随超声的交流电进行的体外实验结果表明，通过抑制扩散边界层，水凝胶对加压素和胰岛素构成的传质屏障均可消除，这表明当使用水凝胶作为超声耦合介质时，只要采用方法诱导凝胶内分子混合，就可实现相对较高速率的声致孔分子透过人体皮肤。
