Advances in Hair Follicle Targeted Drug Delivery: Nanocarriers, Herbal Bioactives and Emerging Therapeutic Applications

Hair follicle targeted drug delivery has emerged as an innovative approach to overcome the limitations of conventional topical therapies, particularly the barrier properties of the stratum corneum that often restrict effective drug penetration into the skin. The hair follicle represents a unique anatomical microenvironment capable of functioning as a localized drug reservoir, allowing enhanced accumulation and prolonged retention of therapeutic agents within the skin. Exploiting the follicular pathway offers promising opportunities for site-specific treatment of a wide range of dermatological and scalp disorders. In recent years, significant progress in formulation science has facilitated the development of advanced carrier systems designed to improve follicular targeting. Various nanoscale delivery platforms including lipid-based nanoparticles, polymeric nanocarriers, nanoemulsions, and vesicular systems have demonstrated substantial potential for enhancing drug deposition within follicular structures. The efficiency of these carriers is strongly influenced by physicochemical attributes such as particle size, surface characteristics, deformability, and lipid composition. Moreover, the integration of bioactive phytoconstituents and antifungal agents into nanocarrier systems has expanded their therapeutic applications in conditions such as dandruff, alopecia, acne, and inflammatory dermatoses. This review summarizes the anatomical and physiological features of hair follicles relevant to drug delivery, discusses the mechanisms governing follicular penetration, and highlights recent advances in nanocarrier-based strategies for targeted dermatological therapy. Emerging perspectives and key challenges associated with follicular drug delivery are also addressed.