title: Novel microstructured sildenafil dosage forms as wound healing promoters.
abstract: OBJECTIVE
  Study the possible benefit of combining biodegradable polymers with sildenafil citrate (SC) in wound healing.
  
  
  METHODS
  Biodegradable micronized powdered formulations of SC were prepared by spray drying using chitosan (P₁) or chitosan/gum Arabic (P₂). Powders were characterized by differential scanning calorimetry, Scanning electron microscope, particle size analysis, flow and swelling behavior. The powders were also incorporated into microstructured gels and in vitro SC release from powders and gels was tested. In vivo wound healing acceleration was tested by measuring area contraction of excision wounds and histologically. Post-healing tensile strength (TS) for incision wounds in rats receiving powder formulations was tested.
  
  
  RESULTS
  The powders were in the micron-size range showing no SC-polymers interaction. Powders had poor flow with angle of repose (θ) of 41 - 48°, and high moisture uptake reaching 107% for placebo powder P₁. Good excision wound healing was seen with P1 and G1 formulations showing 98.4 and 98.5% reduction in wound area, respectively, compared with 83% for the control. Incision wounds were improved with P1 showing TS value of 6.9 compared with 3.7 kg/cm² for control. Histological examinations supported.
  
  
  CONCLUSIONS
  Spray-dried chitosan/SC powder (P₁) and its gel form (G₁) could be promising wound healing promoters as supported by the histological examinations.
authors.affiliation: Alexandria University, Department of Industrial Pharmacy, Faculty of Pharmacy , Alexandria , Egypt +2 03 3630 815 ; +2 03 4873 273 ; wsamy73@yahoo.com , w.sami@bau.edu.lb.
authors.forename: Wael M
authors.initials: WM
authors.lastname: Samy
authors.forename: Asser I
authors.initials: AI
authors.lastname: Ghoneim
authors.forename: Nazik A
authors.initials: NA
authors.lastname: Elgindy
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D048271:Chitosan / Q000737:chemistry; D005260:Female; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D058986:Phosphodiesterase 5 Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D010879:Piperazines / Q000737:chemistry / Q000494:pharmacology*; D011208:Powders; D011687:Purines / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D000068677:Sildenafil Citrate; D012867:Skin / Q000187:drug effects*; D013450:Sulfones / Q000737:chemistry / Q000494:pharmacology*; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011208:Powders; D011687:Purines; D013450:Sulfones; C408130:chitosan citrate; D048271:Chitosan; D000068677:Sildenafil Citrate
keywords: excision; incision; sildenafil citrate; spray drying; wound healing