title: Iontophoresis-targeted, follicular delivery of minoxidil sulfate for the treatment of alopecia.
abstract: Although minoxidil (MX) is a drug known to stimulate hair growth, the treatment of androgenic alopecia could be improved by delivery strategies that would favor drug accumulation into the hair follicles. This work investigated in vitro the potential of iontophoresis to achieve this objective using MX sulfate (MXS), a more water-soluble derivative of MX. Passive delivery of MXS was first determined from an ethanol-water solution and from a thermosensitive gel. The latter formulation resulted in greater accumulation of MXS in the stratum corneum (skin's outermost layer) and hair follicles and an overall decrease in absorption through the skin. Anodal iontophoresis of MXS from the same gel formulation was then investigated at pH 3.5 and pH 5.5. Compared with passive delivery, iontophoresis increased the amount of drug reaching the follicular infundibula from 120 to 600 ng per follicle. In addition, drug recovery from follicular casts was threefold higher following iontophoresis at pH 5.5 compared with that at pH 3.5. Preliminary in vivo experiments in rats confirmed that iontophoretic delivery of MXS facilitated drug accumulation in hair follicles. Overall, therefore, iontophoresis successfully and significantly enhanced follicular delivery of MX suggesting a useful opportunity for the improved treatment of alopecia.
authors: School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-903, Brazil.
authors: Guilherme Martins
authors: GM
authors: Gelfuso
authors: Tais
authors: T
authors: Gratieri
authors: M Begoña
authors: MB
authors: Delgado-Charro
authors: Richard H
authors: RH
authors: Guy
authors: Renata Fonseca
authors: RF
authors: Vianna Lopez
mesh_terms: D000279:Administration, Cutaneous; D000505:Alopecia / Q000188:drug therapy*; D000818:Animals; D016503:Drug Delivery Systems; D018859:Hair Follicle / Q000378:metabolism*; D007478:Iontophoresis; D008297:Male; D008914:Minoxidil / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000378:metabolism; D012869:Skin Absorption; D013552:Swine; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics
chemical_list: D014665:Vasodilator Agents; C039516:minoxidil sulfate ester; D008914:Minoxidil