角质层及其类脂对5-氟脲嘧啶经皮渗透的作用

采用离体皮肤扩散等技术研究了5-Fu在人皮肤各层次中的渗透性质和1,8-CN对药物渗透及皮肤热转变的影响。实验表明5-Fu在皮肤各层次中有相近分配系数,但扩散性质不同。角质层、全皮层、脱脂角质层和去角质层全皮扩散系数依次为1.32×10^-7,1.01×10^-7,1.37×10^-6和54.09×10^-6cm²/h。用1,8-CN处理上述皮肤样品12h后,5-Fu在各组织的分配均减少,角质层和全皮的通透性显著增加(P<0.05),对去脂角质层和去角质层全皮的通透性无明显影响。结合DSC分析证明,角质层是5-Fu经皮渗透的重要屏障,类脂对5-Fu的扩散和1,8-CN的增效具重要意义。

ROLE OF STRATUM CORNEUM AND ITS LIPIDS IN PERMEABILITY OF 5-FLUOROURACIL THROUGH HUMAN SKIN

The role of stratum corneum (SC) and its lipid constituents in skin permeability was assessed in vitro in diffusion system combined with the determination of partition coefficients (PC) and DSC technique. 5-Fu and 1, 8-CN were used as the hydrophilic drug and penetration enhancer, respectively. The results showed that the PCs of 5-Fu were the same in SC, delipid SC, full skin and SC-stripped full skin, but the diffusion coefficients (D) of 5-Fu were different from each other. They were 1.32±0. 37×10^-7, 13.71±5.12×10^-7, 1.01±0.31×10^-7 and 540. 85±50.99±10^-7 cm²/h, respectively. When the skin membranes were pretreated with 1,8-CN for 12 h, the PCs were reduced to similar extent. However, the D was increased significantly in SC and in full skin, there was a small increase for delipid SC. No change was found in the D of stripped skin. DSC analysis indicated that 1, 8-CN might change the thermal behaviour of SC lipid and the influence disappeared when SC was extracted with organic solvent. These results suggest that SC was the main barrier for 5-Fu diffusion through human skin, and the intercellar lipids played an important role for the hydrophilic drug penetration regardless of the presence of the enhancer in SC.