title: Anti-tumor necrosis factor-alpha-loaded microspheres as a prospective novel treatment for Crohn's disease fistulae.
abstract: OBJECTIVE
  Antibodies to tumor necrosis factor alpha (TNF-α) have been successful in treating perianal fistulae in Crohn's disease, but current modes of delivery are limited. Microspheres are currently being assessed as scaffolds for tissue engineering and drug delivery devices. The aim of this study was to produce anti-TNF-α antibody-encapsulated microspheres using thermally induced phase separation (TIPS) and to characterize their behavior.
  
  
  METHODS
  Anti-TNF-α antibody was encapsulated into the microspheres (100 mg infliximab/g poly[lactide-co-glycolide] w/w) using a novel technique combining a vibration encapsulator unit with a TIPS process, using either lyophilized particulate antibody or an aqueous solution of antibody. Microspheres were incubated in phosphate-buffered saline for collection of supernatant and assessment of degradation. The amount and biological activity of the encapsulated antibody released from the microspheres was assessed by enzyme-linked immunosorbent assay and its ability to neutralize recombinant human (rh)TNF-α in vitro with a cytotoxicity assay. An in vitro wound scratch assay was used to assess the effect of released antibody on fibroblast migration. Ultrastructural characteristics of the different microspheres were characterized by scanning electron microscopy.
  
  
  RESULTS
  Highly porous microspheres released anti-TNF-α antibody under zero-order kinetics and inhibited the cytotoxic activity of rhTNF-α, producing a significant increase in cell viability compared with cells treated with rhTNF-α alone. This effect was most pronounced with microspheres fabricated by blending lyophilized particulate anti-TNF-α antibody into the polymer solution, which also significantly reduced the release of lactate dehydrogenase.
  
  
  CONCLUSIONS
  Anti-TNF-α antibody encapsulated into highly porous microspheres was released in a controlled manner and exhibited biological activity against TNF-α. The technique used to produce TIPS microspheres is rapid and provides high encapsulation efficiency. This technique could also be applied to other therapeutic peptides where rapid fabrication and high yields are required.
authors.affiliation: Centre for Gastroenterology and Nutrition, Windeyer Institute, University College London, London, United Kingdom.
authors.forename: Keen Shawn
authors.initials: KS
authors.lastname: Foong
authors.forename: Rishni
authors.initials: R
authors.lastname: Patel
authors.forename: Alastair
authors.initials: A
authors.lastname: Forbes
authors.forename: Richard M
authors.initials: RM
authors.lastname: Day
mesh_terms: D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D002460:Cell Line; D003424:Crohn Disease / Q000628:therapy*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D000069285:Infliximab; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011446:Prospective Studies; D012003:Rectal Fistula / Q000628:therapy*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D014409:Tumor Necrosis Factor-alpha; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D000069285:Infliximab