title: Acid-responsive polymeric nanocarriers for topical adapalene delivery.
abstract: OBJECTIVE
  The acne skin is characteristic of a relatively lower pH microenvironment compared to the healthy skin. The aim of this work was to utilize such pH discrepancy as a site-specific trigger for on-demand topical adapalene delivery.
  
  
  METHODS
  The anti-acne agent, adapalene, was encapsulated in acid-responsive polymer (Eudragit® EPO) nanocarriers via nanoprecipitation. The nanocarriers were characterized in terms of particle size, surface morphology, drug-carrier interaction, drug release and permeation.
  
  
  RESULTS
  Adapalene experienced a rapid release at pH 4.0 in contrast to that at pH 5.0 and 6.0. The permeation study using silicone membrane revealed a significant higher drug flux from the nanocarrier (6.5 ± 0.6 μg.cm(-2).h(-1)) in comparison to that (3.9 ± 0.4 μg.cm(-2).h(-1)) in the control vehicle (Transcutol®). The in vitro pig skin tape stripping study showed that at 24 h post dose-application the nanocarrier delivered the same amount of drug to the stratum corneum as the positive control vehicle did.
  
  
  CONCLUSIONS
  The acid-responsive nanocarriers hold promise for efficient adapalene delivery and thus improved acne therapy.
authors.affiliation: Tianjin Key Laboratory for Modern Drug Delivery & High Efficiency School of Pharmaceutical Science & Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin, 300072, China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Guo
authors.forename: Rajeshree H
authors.initials: RH
authors.lastname: Khengar
authors.forename: Mingjing
authors.initials: M
authors.lastname: Sun
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Aiping
authors.initials: A
authors.lastname: Fan
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000143:Acids / Q000737:chemistry*; D000152:Acne Vulgaris / Q000188:drug therapy; D000068816:Adapalene; D000279:Administration, Cutaneous; D000818:Animals; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry*; D016503:Drug Delivery Systems; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry*; D009281:Naphthalenes / Q000008:administration & dosage* / Q000737:chemistry*; D011108:Polymers / Q000008:administration & dosage / Q000737:chemistry*; D012867:Skin / Q000187:drug effects; D012869:Skin Absorption; D013552:Swine
chemical_list: D000143:Acids; D004337:Drug Carriers; D009281:Naphthalenes; D011108:Polymers; D000068816:Adapalene