title: Thiolated polymers: development and evaluation of transdermal delivery systems for progesterone.
abstract: OBJECTIVE
  To evaluate the possible use of polycarbophil-cysteine (PCP-Cys) as polymeric matrix for transdermal progesterone application.
  
  
  METHODS
  Thiolated polycarbophil was synthesised by the covalent attachment of cysteine to the basis polymer. The adhesive properties of PCP-Cys in comparison to polyvinylpyrrolidone/hydroxypropylmethylcellulose (PVP/HPMC) and polyvinylpyrrolidone/polyvinylalcohol (PVP/PVA) were investigated by testing the total work of adhesion (TWA) on porcine skin. Release studies in Franz diffusion cells and standard in vitro permeation experiments with porcine skin were performed analysing the progesterone content by high-performance liquid chromatography.
  
  
  RESULTS
  Films based on PCP-Cys displayed very high cohesive properties due to the formation of interchain disulfide bonds. The TWA of the thiolated polymer on porcine skin was significantly (P <0.05) the highest. In addition progesterone permeation was also the highest from PCP-Cys compared with PVP/HPMC and PVP/PVA within 24 hours.
  
  
  CONCLUSIONS
  PCP-Cys--a partly thiolated polymer--might be a novel polymer matrix for transdermal progesterone delivery with excellent adhesiveness on porcine skin.
authors.affiliation: Institute of Pharmaceutical Technology and Biopharmaceuticals, University of Vienna, Austria. Claudia.Valenta@univie.ac.at
authors.forename: C
authors.initials: C
authors.lastname: Valenta
authors.forename: A
authors.initials: A
authors.lastname: Walzer
authors.forename: A E
authors.initials: AE
authors.lastname: Clausen
authors.forename: A
authors.initials: A
authors.lastname: Bernkop-Schnürch
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000279:Administration, Cutaneous; D000818:Animals; D002463:Cell Membrane Permeability; D003545:Cysteine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D004337:Drug Carriers; D016503:Drug Delivery Systems; D011374:Progesterone / Q000008:administration & dosage*; D012879:Skin Physiological Phenomena / Q000187:drug effects; D013552:Swine; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D004220:Disulfides; D004337:Drug Carriers; D011374:Progesterone; C030312:calcium polycarbophil; D003545:Cysteine