title: Local delivery of poly lactic-co-glycolic acid microspheres containing imatinib mesylate inhibits intracranial xenograft glioma growth.
abstract: OBJECTIVE
  In an effort to develop new therapeutic strategies to treat malignant gliomas, we have designed poly (lactic-co-glycolic) acid (PLGA) microparticles that deliver imatinib mesylate, a small molecule tyrosine kinase inhibitor. The local continuous release of imatinib mesylate at the tumor site overcomes many obstacles associated with systemic delivery.
  
  
  METHODS
  Polymeric microspheres were prepared from various compositions of PLGA and loaded with imatinib mesylate. Imatinib release profiles, biological activity, and effect on PDGFR-B phosphorylation were confirmed in vitro. The therapeutic efficacy of imatinib microspheres was examined in two s.c. and orthotopic human glioblastoma xenograft models.
  
  
  RESULTS
  A single local injection of PLGA microspheres loaded with a low concentration of imatinib mesylate led to 88% and 79% reduction in s.c. human (U87-MG) and murine (GL261) glioma tumors, respectively. PLGA-imatinib mesylate administered intracranially led to a 79% reduction in U87MG tumor volume. Immunohistochemical analysis showed a marked decrease in proliferation indices and tumor vessel density in the s.c. model and induction of apoptosis in an intracranial model.
  
  
  CONCLUSIONS
  This is the first study to show the therapeutic efficacy of the local delivery of imatinib mesylate using a polymeric delivery system.
authors.affiliation: The Faculty of Biotechnology and Food Engineering, The Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Ofra
authors.initials: O
authors.lastname: Benny
authors.forename: Lata G
authors.initials: LG
authors.lastname: Menon
authors.forename: Gilert
authors.initials: G
authors.lastname: Ariel
authors.forename: Effrat
authors.initials: E
authors.lastname: Goren
authors.forename: Seung-Ki
authors.initials: SK
authors.lastname: Kim
authors.forename: Chaney
authors.initials: C
authors.lastname: Stewman
authors.forename: Peter M
authors.initials: PM
authors.lastname: Black
authors.forename: Rona S
authors.initials: RS
authors.lastname: Carroll
authors.forename: Marcelle
authors.initials: M
authors.lastname: Machluf
mesh_terms: D000818:Animals; D001549:Benzamides; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005910:Glioma / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D000068877:Imatinib Mesylate; D019344:Lactic Acid / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008863:Microspheres; D010766:Phosphorylation; D010879:Piperazines / Q000008:administration & dosage*; D011100:Polyglycolic Acid / Q000008:administration & dosage*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011743:Pyrimidines / Q000008:administration & dosage*; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D000068877:Imatinib Mesylate; D020797:Receptor, Platelet-Derived Growth Factor beta