title: Preparation and characterization of PEG-modified polyurethane pressure-sensitive adhesives for transdermal drug delivery.
abstract: BACKGROUND
  The purpose of this work was to develop novel pressure-sensitive adhesives (PSAs) for transdermal drug-delivery systems (TDDS) with proper adhesive properties, hydrophilicity, biocompatibility and high drug loading.
  
  
  METHODS
  Polyethyleneglycol-modified polyurethane PSAs (PEG-PU-PSAs) were synthesized by prepolymerization method with PEG-modified co-polyether and hexamethylene diisocyanate. The effects of reaction temperature, catalyst, ratios of NCO/OH, co-polyether composition, and chain extender were investigated. Drug loading was studied by using thiamazole (hydrophilic drug), diclofenac sodium (slightly hydrophilic drug), and ibuprofen (lipophilic drug) as model drugs. In vitro drug-release kinetics obtained with Franz diffusion cell and dialysis membrane.
  
  
  RESULTS
  The results showed that when reaction temperature at 80 degrees C, weight percentage of stannous octoate as catalyst at 0.05%, ratio of NCO/OH at 2.0-2.2, ratio of PEG/polypropylene glycol (PPG)/polytetramethylene ether glycol (PTMG) at 30/25-30/50-55, and weight percentage of glycol as chain extender at 4.5%, PEGPU-PSAs synthesized performed well on adhesive properties. Actually, PEG on the main chain of the PU could improve the hydrophilicity of PSAs, whereas PPG and PTMG could offer proper adhesive properties. Skin compatibility test on volunteers indicated that PEG-PU-PSAs would not cause any skin irritations. All the model drugs had excellent stabilizations in PEG-PU-PSAs. In vitro drug-release kinetics demonstrated that the drug release depended on drug-loading level and solubility of the drug.
  
  
  CONCLUSIONS
  These experimental results indicated that PEG-PU-PSAs have good potential for applications in TDDS.
authors.affiliation: School of Chemical Engineering and Materials, Huangshi Institute of Technology, Huangshi, China.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Zhao
authors.forename: Lingyu
authors.initials: L
authors.lastname: Jiang
authors.forename: Huibi
authors.initials: H
authors.lastname: Xu
authors.forename: Xiangliang
authors.initials: X
authors.lastname: Yang
mesh_terms: D000269:Adhesives / Q000737:chemistry; D000279:Administration, Cutaneous; D002208:Caproates / Q000737:chemistry; D003485:Cyanates / Q000737:chemistry; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry; D016503:Drug Delivery Systems; D005260:Female; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage / Q000737:chemistry; D017953:Isocyanates; D008297:Male; D008713:Methimazole / Q000008:administration & dosage / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000633:toxicity; D011108:Polymers / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry* / Q000633:toxicity; D023422:Skin Irritancy Tests; D012995:Solubility; D013696:Temperature; D014001:Tin
chemical_list: D000269:Adhesives; D002208:Caproates; D003485:Cyanates; D017953:Isocyanates; D011108:Polymers; D011140:Polyurethanes; C015262:1,6-hexamethylene diisocyanate; D004008:Diclofenac; D011092:Polyethylene Glycols; C419565:2-ethylhexanoic acid tin(II) salt; D008713:Methimazole; D014001:Tin; D007052:Ibuprofen