The skin is a complex organ with a heterogeneous structure. While the outermost layer, the stratum corneum, is lipophilic, meaning it attracts and retains lipids, the inner layers (epidermis and dermis) are hydrophilic, meaning they attract and retain water.
This unique structure allows the skin to act as a barrier, preventing the entry of harmful substances while allowing the passage of necessary nutrients and moisture.
- Lipophilic substances, which are fat-soluble, can penetrate the stratum corneum relatively easily.
- Hydrophilic substances, which are water-soluble, face a greater challenge in penetrating the stratum corneum and often require the assistance of penetration enhancers or specialized delivery systems.
Overall, the skin's lipophilicity is primarily associated with the stratum corneum, while the inner layers exhibit a more hydrophilic nature.
