title: Controlled delivery of the anti-VEGF aptamer EYE001 with poly(lactic-co-glycolic)acid microspheres.
abstract: OBJECTIVE
  To develop a controlled-drug delivery system for the long-term inhibition of vascular endothelial growth factor (VEGF) and its mediated responses.
  
  
  METHODS
  Poly(lactic-co-glycolic)acid (PLGA) microspheres containing anti-VEGF RNA aptamer (EYE001) formulations in the solid-state were developed by an oil-in-oil solvent evaporation process. In vitro experiments were performed to characterize the release profiles. Stability and bioactivity of the released drug were assayed by monitoring the RNA aptamer's ability to inhibit VEGF-induced cell proliferation in human umbilical vein endothelial cells (HUVECs). Cell proliferation experiments were conducted with aptamer aliquots collected after short-, mid-, and long-term release time points. To investigate the feasibility of this polymer device as a potential transscleral delivery device, an in vitro apparatus was developed to assess polymer hydration and degradation through rabbit sclera and subsequent delivery through it.
  
  
  RESULTS
  PLGA microspheres were able to deliver EYE001 in a sustained manner, with an average rate of 2 micro g/d over a period of 20 days. Solid-state stabilization of the aptamer with disaccharide trehalose before lyophilization and encapsulation in PLGA rendered the drug more stable after release. Cell proliferation experiments demonstrated that the bioactivity of the aptamer was preserved after release, as indicated by inhibition of endothelial cell proliferation after incubation with VEGF. Microspheres packed into a sealed chamber and placed onto the "orbital" part of a rabbit sclera for a period of 6 days became hydrated and started to degrade, as shown by scanning electron microscopy (SEM). As a result, the aptamer was delivered from the microspheres through the sclera, as determined spectrophotometrically.
  
  
  CONCLUSIONS
  The loading of aptamer-containing microspheres into a device and placing it on the orbital surface of the sclera was assessed and shown to be feasible. RNA aptamer EYE001 encapsulated in PLGA was delivered over a period of 20 days with retained activity. This method represents a promising approach for the transscleral delivery of drugs and the treatment of choroidal and retinal diseases.
authors.affiliation: Angiogenesis and Retina Research Laboratory, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, 325 Cambridge Street, Boston, MA 02114, USA.
authors.forename: Karen G
authors.initials: KG
authors.lastname: Carrasquillo
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Ricker
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Rigas
authors.forename: Joan W
authors.initials: JW
authors.lastname: Miller
authors.forename: Evangelos S
authors.initials: ES
authors.lastname: Gragoudas
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Adamis
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002942:Circular Dichroism; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004730:Endothelium, Vascular / Q000187:drug effects*; D006801:Humans; D019344:Lactic Acid; D008863:Microspheres; D009841:Oligonucleotides / Q000008:administration & dosage*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D011817:Rabbits; D012590:Sclera / Q000187:drug effects / Q000648:ultrastructure; D014471:Umbilical Veins
chemical_list: D001672:Biocompatible Materials; D004337:Drug Carriers; D009841:Oligonucleotides; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C430291:NX1838