title: Preparation and evaluation of liquid-crystal formulations with skin-permeation-enhancing abilities for entrapped drugs.
abstract: The usefulness of liquid crystals (LC) in topical formulations for application to skin was evaluated by measuring the in vitro permeation profile of a model compound, calcein, entrapped in a LC formulation, through excised hairless rat skin and a three-dimensional cultured human-skin model; the viability was determined using the MTT assay. Two physically stable LCs were prepared from a mixture of mono-, di-, and tri-esters 1, and monoesters 2, composed of erythritol and phytanylacetic acid. Cryo-transmission electron microscopy (cryo-TEM), electron diffraction patterns, and small-angle X-ray diffraction (SAXS) observations of the LC nanodispersions showed that the structures of the LCs were reverse hexagonal (LC-A) and cubic (LC-B). The skin-permeation properties of calcein were enhanced by entrapping in the LCs as a result of the increase in calcein partition from the LC dispersion solution into the skin; the properties were analyzed using a skin-permeation-time profile. Drug partitioning could also be modified by the LC structure. No skin damage was caused by the LC formulation in these experiments.The present study suggests that LC dispersions are potential additives in topical drug formulations and cosmetic formulations.
authors.affiliation: Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamada
authors.forename: Jun
authors.initials: J
authors.lastname: Yamashita
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Todo
authors.forename: Keiko
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Satoru
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tokudome
authors.forename: Fumie
authors.initials: F
authors.lastname: Hashimoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Sugibayashi
mesh_terms: D000279:Administration, Cutaneous; D000287:Administration, Topical; D000818:Animals; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D020285:Cryoelectron Microscopy / Q000379:methods; D004337:Drug Carriers / Q000138:chemical synthesis* / Q000737:chemistry; D004353:Drug Evaluation, Preclinical; D004526:Efficiency; D006801:Humans; D050866:Liquid Crystals / Q000737:chemistry*; D008297:Male; D019999:Pharmaceutical Solutions / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051381:Rats; D054772:Rats, Hairless; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012869:Skin Absorption / Q000187:drug effects
chemical_list: D004337:Drug Carriers; D019999:Pharmaceutical Solutions