Panax notoginseng saponins loaded W/O microemulsion for alopecia therapy with panthenol as cosurfactant to reduce skin irritation.

The etiology of alopecia is so complex that current therapies with single-mechanism and attendant side-effects during long-term usage, are insufficient for treatment. Panax notoginseng saponins (PNS) is supposed to treat alopecia with multiple mechanisms, but difficult to penetrate skin efficiently due to water-solubility. Here, we designed water-in-oil microemulsion (PNS ME) using jojoba oil, fractioned coconut oil, RH 40 + Span 80 and cosurfactant D-panthenol, to help PNS penetrating the skin. Particularly, D-panthenol not only enlarges the microemulsion area, reduces the usage amounts of surfactants thus relieves skin irritation, but stimulates the migration of dermal papilla cells (DPCs), displaying cooperative effects on anti-alopecia. PNS ME penetrates through sebum-rich corneum via high-affinity lipid fusion, targets to hair follicles (HFs), where it resides in skin for sustained drug release, accelerates angiogenesis to build well-nourished environment for HFs, and facilitates the proliferation and migration of DPCs in vitro. PNS ME markedly improved hair density, skin pigmentation, new hair weight, skin thickness, and collagen generation of telogen effluvium mice. Moreover, PNS also took outstanding curative effects on androgenetic alopecia mice. Upon further exploration, PNS ME caused dramatic upregulations of β-catenin, VEGF and Ki67, suggesting it might function by triggering Wnt/β-catenin pathway, accelerating vessels formation, and activating the hair follicle stem cells. Notably, PNS ME indicated longer-term safety than minoxidil tincture. Together, PNS ME provides a comprehensive strategy for alopecia, especially it avoids defects by high-proportioned surfactants in traditional microemulsion, exhibiting milder and safer, which shows bright prospect of applying microemulsion in hair growth promotion.