title: The effect of pH on the degradation of biodegradable poly(L-lactide-co-glycolide) 80/20 urethral stent material in vitro.
abstract: OBJECTIVE
  To investigate in vitro whether pH ranging between 6 and 9 has an effect on the degradation of stent fibers made of poly(l-lactide-co-glycolide) (PLGA) 80/20.
  
  
  METHODS
  The fibers were divided into three groups and immersed in sodium phosphate-buffered saline (Na-PBS) solution with three different pH values: 6, 7.4, and 9. The mechanical and thermal properties were studied, and scanning electron microscopy (SEM) images were taken at specific time points of hydrolysis.
  
  
  RESULTS
  The tensile testing showed that the strength of the fibers decreased through hydrolysis and was lost at 8 weeks in all groups. The T(m) and T(g) of the PLGA fibers did not indicate any significant differences between the different groups. In SEM images taken at 4 weeks, there were no significant differences between the fibers immersed in Na-PBS solutions of different pH values. However, at 8 weeks the surface of the fiber immersed in saline with a pH of 6 seemed coarser than that of those immersed in neutral (pH 7.4) or alkaline (pH 9) Na-PBS.
  
  
  CONCLUSIONS
  The studied pH values did not influence the degradation behavior of the PLGA 80/20 fibers. Therefore, rabbits can be used as model animals for human biodegradable urological devices even though the pH of their urine is different.
authors.affiliation: Department of Biomedical Engineering, Tampere University of Technology, Tampere, Finland.
authors.forename: Hanne
authors.initials: H
authors.lastname: Juuti
authors.forename: Andres
authors.initials: A
authors.lastname: Kotsar
authors.forename: Joonas
authors.initials: J
authors.lastname: Mikkonen
authors.forename: Taina
authors.initials: T
authors.lastname: Isotalo
authors.forename: Martti
authors.initials: M
authors.lastname: Talja
authors.forename: Teuvo L J
authors.initials: TL
authors.lastname: Tammela
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
authors.forename: Minna
authors.initials: M
authors.lastname: Kellomäki
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D001673:Biodegradation, Environmental / Q000187:drug effects; D002152:Calorimetry, Differential Scanning; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D019344:Lactic Acid / Q000494:pharmacology*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011100:Polyglycolic Acid / Q000494:pharmacology*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011817:Rabbits; D015607:Stents; D013696:Temperature; D013718:Tensile Strength / Q000187:drug effects; D014521:Urethra / Q000187:drug effects*
chemical_list: D001672:Biocompatible Materials; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid