title: Chitosan microparticles for sustaining the topical delivery of minoxidil sulphate.
abstract: Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (∼82%), a mean diameter of 3.0 µm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Av. do Café, s/n. 14040-903, Ribeirão Preto, SP, Brazil.
authors.forename: Guilherme Martins
authors.initials: GM
authors.lastname: Gelfuso
authors.forename: Taís
authors.initials: T
authors.lastname: Gratieri
authors.forename: Patrícia Sper
authors.initials: PS
authors.lastname: Simão
authors.forename: Luís Alexandre Pedro
authors.initials: LA
authors.lastname: de Freitas
authors.forename: Renata Fonseca Vianna
authors.initials: RF
authors.lastname: Lopez
mesh_terms: D000287:Administration, Topical; D048271:Chitosan / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D008863:Microspheres; D008914:Minoxidil / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D010316:Particle Size; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology
chemical_list: D014665:Vasodilator Agents; C039516:minoxidil sulfate ester; D008914:Minoxidil; D048271:Chitosan