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Iontophoresis-targeted, follicular delivery of minoxidil sulfate for the treatment of alopecia

Authors

  • Guilherme Martins Gelfuso,

    1. School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-903, Brazil
    2. Department of Pharmacy & Pharmacology, University of Bath, Bath, BA2 4LZ, UK
    3. School of Health Sciences, University of Brasília, Brasília, DF, 70910-900, Brazil
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  • Tais Gratieri,

    1. School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-903, Brazil
    2. School of Health Sciences, University of Brasília, Brasília, DF, 70910-900, Brazil
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  • M. Begoña Delgado-Charro,

    1. Department of Pharmacy & Pharmacology, University of Bath, Bath, BA2 4LZ, UK
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  • Richard H. Guy,

    1. Department of Pharmacy & Pharmacology, University of Bath, Bath, BA2 4LZ, UK
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  • Renata Fonseca Vianna Lopez

    Corresponding author
    1. School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-903, Brazil
    • School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, 14040-903, Brazil. Telephone: +55-16-36024202; Fax: +55-16-36024202
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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. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1488–1494, 2013

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