FIGURE 1.

Transdermal penetration of HA2k in three‐dimensional cultured human epidermis and excised human skin.

In the upper panel (A), 1% fluorescein‐labeled HA2k and 8‐kDa HA were applied to a 3D skin model. The HA2k passed through the stratum corneum, whereas the 8‐kDa HA did not. Magnification, x200; scale bars, 50 μm. In the lower panel (B), 0.1% fluorescein‐labeled HA2k and 1000‐kDa HA were applied to a human skin sample. The HA2k passed through the stratum corneum, whereas the 1000‐kDa HA did not. Magnification, x100; scale bars, 100 μm