State Key Laboratory of Fine Chemicals, Department of Pharmaceutical Engineering, School of Chemical Engineering, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Liaoning, 116024, People's Republic of China.
AAPS J. 2024 Jul 2;26(4):76. doi: 10.1208/s12248-024-00941-7.
The selection of skin is crucial for the in vitro permeation test (IVPT). The purpose of this study was to investigate the influence of different freezing-thawing processes on the barrier function of skin and the transdermal permeability of granisetron and lidocaine. Rat and hairless mouse skins were thawed at three different conditions after being frozen at -20℃ for 9 days: thawed at 4℃, room temperature (RT), and 32℃. There were no significant differences in the steady-state fluxes of drugs between fresh and thawed samples, but compared with fresh skin there were significant differences in lag time for the permeation of granisetron in rat skins thawed at RT and 32℃. Histological research and scanning electron microscopy images showed no obvious structural damage on frozen/thawed skin, while immunohistochemical staining and enzyme-linked immunosorbent assay for the tight junction (TJ) protein Cldn-1 showed significantly impaired epidermal barrier. It was concluded that the freezing-thawing process increases the diffusion rate of hydrophilic drugs partly due to the functional degradation of TJs. It's recommended that hairless, inbred strains and identical animal donors should be used, and the selected thawing method of skin should be validated prior to IVPT, especially for hydrophilic drugs.
皮肤的选择对于体外渗透试验（IVPT）至关重要。本研究旨在探讨不同的冻融过程对皮肤屏障功能和格拉司琼及利多卡因经皮渗透的影响。将大鼠和无毛小鼠皮肤在 -20℃冷冻 9 天后，分别在 4℃、室温（RT）和 32℃三种不同条件下解冻：三种条件下冻融皮肤的药物稳态通量与新鲜皮肤无显著差异，但与新鲜皮肤相比，在 RT 和 32℃解冻的大鼠皮肤中，格拉司琼渗透的滞后时间有显著差异。组织学研究和扫描电子显微镜图像显示，冻融皮肤无明显的结构损伤，而紧密连接（TJ）蛋白 Claudin-1 的免疫组织化学染色和酶联免疫吸附试验显示，表皮屏障功能明显受损。结论是，冻融过程会增加亲水性药物的扩散速率，部分原因是 TJ 的功能下降。建议在 IVPT 之前，应使用无毛、近交系和相同的动物供体，并验证所选的皮肤解冻方法，特别是对于亲水性药物。
