title: Development of biodegradable poly(propylene fumarate)/poly(lactic-co-glycolic acid) blend microspheres. I. Preparation and characterization.
abstract: We developed poly(propylene fumarate)/poly(lactic-co-glycolic acid) (PPF/PLGA) blend microspheres and investigated the effects of various processing parameters on the characteristics of these microspheres. The advantage of these blend microspheres is that the carbon-carbon double bonds along the PPF backbone could be used for their immobilization in a PPF scaffold. Microspheres containing the model drug Texas red dextran were fabricated using a double emulsion-solvent extraction technique. The effects of the following six processing parameters on the microsphere characteristics were investigated: PPF/PLGA ratio, polymer viscosity, vortex speed during emulsification, amount of internal aqueous phase, use of poly(vinyl alcohol) (PVA) in the internal aqueous phase, and PVA concentration in the external aqueous phase. Our results showed that the microsphere surface morphology was affected most by the viscosity of the polymer solution. Microspheres fabricated with a kinematic viscosity of 39 centistokes had a smooth, nonporous surface. In most microsphere formulations, the model drug was dispersed uniformly in the polymer matrix. For all fabricated formulations, the average microsphere diameter ranged between 19.0 and 76.9 microm. The external PVA concentration and vortex speed had most effect on the size distribution. Entrapment efficiencies varied from 60 to 98% and were most affected by the amount of internal aqueous phase, vortex speed, and polymer viscosity. Overall, we demonstrated the ability to fabricate PPF/PLGA blend microspheres with similar surface morphology, entrapment efficiency, and size distribution as conventional PLGA microspheres.
authors.affiliation: Tissue Engineering & Polymeric Biomaterials Laboratory, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905, USA.
authors.forename: Diederik H R
authors.initials: DH
authors.lastname: Kempen
authors.forename: Lichun
authors.initials: L
authors.lastname: Lu
authors.forename: Xun
authors.initials: X
authors.lastname: Zhu
authors.forename: Choll
authors.initials: C
authors.lastname: Kim
authors.forename: Esmaiel
authors.initials: E
authors.lastname: Jabbari
authors.forename: Wouter J A
authors.initials: WJ
authors.lastname: Dhert
authors.forename: Bradford L
authors.initials: BL
authors.lastname: Currier
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Yaszemski
mesh_terms: D001672:Biocompatible Materials / Q000302:isolation & purification*; D001673:Biodegradation, Environmental; D016503:Drug Delivery Systems; D005650:Fumarates / Q000302:isolation & purification*; D006016:Glycolates / Q000302:isolation & purification*; D019344:Lactic Acid; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011126:Polypropylenes / Q000302:isolation & purification*; D013499:Surface Properties; D014783:Viscosity; D014867:Water; D014966:Xanthenes
chemical_list: D001672:Biocompatible Materials; D005650:Fumarates; D006016:Glycolates; D011126:Polypropylenes; D014966:Xanthenes; C097850:poly(propylene fumarate); D014867:Water; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C034657:Texas red