title: Preparation and in vitro characterization of vascular endothelial growth factor (VEGF)-loaded poly(D,L-lactic-co-glycolic acid) microspheres using a double emulsion/solvent evaporation technique.
abstract: Biodegradable Poly(lactic-co-glycolic acid; PLGA), microspheres encapsulating the angiogenic protein recombinant human vascular endothelial growth factor (rhVEGF) were formed to achieve VEGF release in a sustained manner. These microspheres are a promising delivery system which can be used for therapeutic angiogenesis. The PLGA microspheres incorporating two different initial loading amounts of rhVEGF have been prepared by a modified water-in-oil-in-water (w/o/w) double emulsion/solvent evaporation technique. The microspheres have been characterized by particle size distribution, environmental scanning electron microscopy (ESEM), light microscopy, encapsulation efficiency and their degradation was studied in vitro. The rhVEGF released from microspheres was quantified by the competitive enzyme-linked immunosorbent assay (ELISA) and human umbilical vein endothelial cell (HUVEC) proliferation assay was used to assess biological activity of the released VEGF. The microspheres were spherical with diameters of 10-60 µm and the encapsulation efficiency was between 46% and 60%. The release kinetics of rhVEGF was studied for two different amounts: 5 µg VEGF (V5) and 50 µg VEGF (V50) per 500 mg starting polymer. The total protein (VEGF:BSA) release increased up to 4 weeks for two rhVEGF concentrations. The ELISA results showed that the burst release for V5 and V50 microspheres were 4 and 27 ng/mL, respectively. For V5, the microspheres showed an initial burst release, followed by a higher steady-state release until 14 days. VEGF release increased up to 2 weeks for V50 microsphere. HUVEC proliferation assay showed that endothelial cells responded to bioactive VEGF by proliferating and migrating.
authors.affiliation: TUBITAK, Marmara Research Center, Genetic Engineering and Biotechnology Institute, P.O. Box 21, 41470 Gebze-Kocaeli, Turkey. oksan.yilmaz@mam.gov.tr
authors.forename: Okşan
authors.initials: O
authors.lastname: Karal-Yılmaz
authors.forename: Müge
authors.initials: M
authors.lastname: Serhatlı
authors.forename: Kemal
authors.initials: K
authors.lastname: Baysal
authors.forename: Bahattin M
authors.initials: BM
authors.lastname: Baysal
mesh_terms: D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004339:Drug Compounding / Q000379:methods*; D004655:Emulsions / Q000737:chemistry; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D012997:Solvents / Q000737:chemistry; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D003692:Delayed-Action Preparations; D004655:Emulsions; D011994:Recombinant Proteins; D012997:Solvents; D042461:Vascular Endothelial Growth Factor A; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid