Purpose: Characterization of liposomes and ethosomes containing hidrophobic minoxidil (Mx) for topical administration was carried out in order to investigate the effect of preparation method and composition variables in flux properties of minoxidil through rat skin and its targeting to pilosebaceous structures. Methods: MLV liposomes and ethosomes were prepared by mechanical dispersion or Bangham method. Characterization was carried out attending to size, as a measure of stability, entrapment efficacy, morphology and lamellarity of the vesicles. Permeation studies through rat skin were conducted by means of Franz diffusion cells for all the batches investigated. In order to analize the preferential pathway of Mx across the stratum corneum toward the pilosebaceus unity, a fluorescent probe (b-carotene, bC) was used as a model drug for Confocal Laser Scanning Microscopy (CLSM) assays. Results: Mean size, entrapment efficacy, outer morphology and lamellarity were strongly influenced by the relative amount of cholesterol in the composition of the vesicles and by the presence or absence of ethanol in the medium. Flux properties of minoxidil from all systems depended as well on the cholesterol amount and the presence of ethanol in the formulation. In all cases, ethosomes exhibit better values of flux through rat skin than liposomes. All systems investigated by CLSM were compared with regard to the penetration depth of the fluorescent probe into the stratum corneum and the relative intensity of fluorescence at the pilosebaceous level. Ethosome formulation with 40 % of cholesterol (total lipid weight) showed the highest values for flux of Mx and the best targeting ability. Conclusions: DPPC vesicles were effective in delivering Mx through stratum corneum of rat skin, showing a strongly increase with regard to the drug as such. Ethosomes demonstrated to be the best formulation assayed in the targeting of the drug to the pilosebaceous structures.
PPC vesicles containing minoxidil I: characterization and in vitro permeation studies through rat skin / J.M. López-Pinto; J. Palma; M.L. González-Rodríguez; A. Fini; A.M. Rabasco. - STAMPA. - (2004), p. 68. (Intervento presentato al convegno European Conference on Drug delivery and Pharmaceutical Technology tenutosi a Sevilla (Spain) nel May 10-12, 2004).
PPC vesicles containing minoxidil I: characterization and in vitro permeation studies through rat skin
FINI, ADAMO;
2004
Abstract
Purpose: Characterization of liposomes and ethosomes containing hidrophobic minoxidil (Mx) for topical administration was carried out in order to investigate the effect of preparation method and composition variables in flux properties of minoxidil through rat skin and its targeting to pilosebaceous structures. Methods: MLV liposomes and ethosomes were prepared by mechanical dispersion or Bangham method. Characterization was carried out attending to size, as a measure of stability, entrapment efficacy, morphology and lamellarity of the vesicles. Permeation studies through rat skin were conducted by means of Franz diffusion cells for all the batches investigated. In order to analize the preferential pathway of Mx across the stratum corneum toward the pilosebaceus unity, a fluorescent probe (b-carotene, bC) was used as a model drug for Confocal Laser Scanning Microscopy (CLSM) assays. Results: Mean size, entrapment efficacy, outer morphology and lamellarity were strongly influenced by the relative amount of cholesterol in the composition of the vesicles and by the presence or absence of ethanol in the medium. Flux properties of minoxidil from all systems depended as well on the cholesterol amount and the presence of ethanol in the formulation. In all cases, ethosomes exhibit better values of flux through rat skin than liposomes. All systems investigated by CLSM were compared with regard to the penetration depth of the fluorescent probe into the stratum corneum and the relative intensity of fluorescence at the pilosebaceous level. Ethosome formulation with 40 % of cholesterol (total lipid weight) showed the highest values for flux of Mx and the best targeting ability. Conclusions: DPPC vesicles were effective in delivering Mx through stratum corneum of rat skin, showing a strongly increase with regard to the drug as such. Ethosomes demonstrated to be the best formulation assayed in the targeting of the drug to the pilosebaceous structures.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
