title: Enhanced bioavailability of L-carnitine after painless intradermal delivery vs. oral administration in rats.
abstract: OBJECTIVE
  In vitro and in vivo permeation studies were conducted to evaluate the characteristic of percutaneous administration of high hydrophilic drug L-carnitine (LC) by Functional MicroArray (FMA) painless intradermal delivery system.
  
  
  METHODS
  In vitro study was designed to assess the effects of various skins, donor concentration and hydrogels from different carbomer derivatives on the release of LC in a Franz-type diffusion cell. The LC gel patches with carbomer 980 P were prepared and successfully applied to pharmacokinetic study of SD rats with and without FMA. Intravenous injection and oral administration were performed to support pharmacokinetic calculations and comparison of bioavailability.
  
  
  RESULTS
  Enhanced delivery of LC using FMA was achieved in skin of different species in vitro studies. The 750 mg LC gel patches were applied to rats over 6 h, and approximately 27% of loaded dose was transported into rat. A 2.8-fold enhancement of absolute bioavailability for LC with FMA intradermal delivery system was observed compared with oral LC administration in vivo study.
  
  
  CONCLUSIONS
  Both in vitro and in vivo studies demonstrated that the FMA intradermal delivery system can enhance the delivery and bioavailability of LC.
authors.affiliation: Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Suohui
authors.initials: S
authors.lastname: Zhang
authors.forename: Guangjiong
authors.initials: G
authors.lastname: Qin
authors.forename: Yan
authors.initials: Y
authors.lastname: Wu
authors.forename: Yunhua
authors.initials: Y
authors.lastname: Gao
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Qiu
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Bai
authors.initials: B
authors.lastname: Xu
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002331:Carnitine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D016503:Drug Delivery Systems / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D066298:In Vitro Techniques; D007271:Injections, Intradermal; D008297:Male; D008845:Microinjections / Q000295:instrumentation / Q000379:methods*; D009339:Needles; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000378:metabolism; D012869:Skin Absorption; D013552:Swine; D014018:Tissue Distribution
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; C479038:carbomer; D002331:Carnitine
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