New topical antiandrogenic formulations can stimulate hair growth in human bald scalp grafted onto mice

The purpose of this study was to test the ability of topical formulations of finasteride and flutamide to re-enlarge hair follicles in male-pattern baldness. This was evaluated by an experimental model of human scalp skin graft transplanted onto SCID mice. A comparison was made between formulations containing finasteride and flutamide, and a vehicle formulation in terms of the mean hairs per graft, length, diameter of the shafts, and structures of the growth stages of the hair. Flutamide and finasteride had a significantly higher effect (P<0.05) than the placebo in all the tested parameters, but flutamide demonstrated more hair per graft and longer hair shafts than finasteride (P<0.05). The number of hairs per graft for flutamide and finasteride groups were 1.22±0.47 and 0.88±0.95 hairs/0.5 mm2 graft, respectively, versus 0.35±0.6 hairs/graft for vehicle-treated graft. Similarly, hair lengths for flutamide and finasteride were 5.82±0.50 and 4.50±0.32 mm, respectively, versus 2.83±0.18 mm for the vehicle-treated grafts. An in vitro diffusion study of flutamide gel using hairless mouse skin demonstrated the beneficial effect of the vehicle composition in comparison with a hydroalcoholic solution or a gel containing no penetration enhancer. It is therefore suggested that this topical composition containing flutamide or finasteride may effectively result in regression of male-pattern baldness.