title: Stability of prostaglandin E(2) (PGE (2)) embedded in poly-D,L: -lactide-co-glycolide microspheres: a pre-conditioning approach for tissue engineering applications.
abstract: Prostaglandin E(2) (PGE(2)) is involved in angiogenesis, bone repair and cartilage metabolism. Thus, PGE(2) might represent a suitable signaling molecule in different tissue engineering applications. PGE(2) also has a short half-life time. Its incorporation into poly-D: ,L: -lactide-co-glycolide (PLGA) microspheres was demonstrated in a previous study. However, the stability of bioactive PGE(2) in these microspheres is unknown. With an adjusted mass spectrometry assay we investigated the amount of incorporated PGE(2) and the stability of PGE(2) in conventional cell culture medium and in PLGA microspheres. The stability of PGE(2) was closely pH dependent. Strong acidic or basic environments reduced the half-life from 300 h (pH 2.6-4.0) to below 50 h at pH 2.0 or pH 8.8. The half-life of PGE(2) incorporated into poly-D: ,L: -lactide-co-glycolide increased drastically to 70 days at 37 degrees C and to 300 days at 8 degrees C. Analysis with scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated a distinct nanostructure of the polymeric phase and both nano- and microporosity.
authors.affiliation: Mother-Child Medical Center, Department of Pediatric Science, Philipps-University, Marburg, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Watzer
authors.forename: Rolf
authors.initials: R
authors.lastname: Zehbe
authors.forename: Sven
authors.initials: S
authors.lastname: Halstenberg
authors.forename: C
authors.initials: C
authors.lastname: James Kirkpatrick
authors.forename: Christoph
authors.initials: C
authors.lastname: Brochhausen
mesh_terms: D002853:Chromatography, Liquid; D015232:Dinoprostone / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D004355:Drug Stability; D008401:Gas Chromatography-Mass Spectrometry; D006207:Half-Life; D019344:Lactic Acid / Q000737:chemistry*; D013058:Mass Spectrometry; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D004337:Drug Carriers; D011108:Polymers; D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D015232:Dinoprostone