Follicular Transport Route: Research Progress and Future Perspectives

The document highlighted the significant role of hair follicles in the penetration and storage of topically applied compounds, validated through various animal and human studies. It discussed how follicular penetration rates varied based on regional differences and functional status. Advances were made in targeting hair follicle-associated cells, such as antigen-presenting cells and stem cells. Improved methods like differential stripping, spectrophotometry, and confocal laser scanning microscopy helped determine penetration profiles and kinetics for various drugs and delivery systems. The study found that particulate delivery systems aggregated in hair follicle openings and penetrated the follicular duct in a size-dependent manner, leading to new concepts in targeted drug delivery using solid and semi-solid particles. The review emphasized the need for pilot studies in human volunteers to advance clinical applications for follicular targeting.