Controlled release of the fibronectin central cell binding domain from polymeric microspheres.
Non-ionic surfactants have been employed as alternatives to PVA for the emulsification-encapsulation of a conformationally labile protein (FIII9'-10) into PLGA microspheres. FIII9'-10 was encapsulated using a w/o/w double emulsification-evaporation technique and the microspheres fabricated were characterized by SEM and CLSM. The peptide backbone integrity of FIII9'-10 was assayed by SDS-PAGE and the degree of unfolding of FIII9'-10 following emulsification-encapsulation was assessed using a fibroblast cell-attachment assay. The encapsulation efficiency for FIII9'-10 was 25% when using PVA, compared to 50-60% when using Igepal CA-630 or Triton-X100, with values below for the other surfactants. FIII9'-10 released from microspheres promoted cell attachment in a concentration-dependent manner, only Igepal CA-630 and Triton X-100 maintaining near-maximal cell attachment, indicating that the conformation of the relatively unstable FIII9' domain was preserved. All non-ionic surfactants reduced microsphere surface porosity, compared to PVA, and an increasing surface rugosity (leading to minor 'ridges') could be correlated with decreasing surfactant HLB. Low surface porosities did not effect the diffusion of FIII9'-10 from the microspheres' internal pores in a 'burst release', as may have been imagined. In summary, non-ionic surfactants should be considered over PVA for the maintenance of biological activity of conformationally labile proteins during encapsulation.
Bouissou
Camille
C
Department of Pharmacy and Pharmacology, University of Bath, Bath, UK.
Potter
Ursula
U
Altroff
Harri
H
Mardon
Helen
H
Van Der Walle
Christopher
C
D000818:Animals; D001665:Binding Sites / Q000187:drug effects; D002417:Cattle; D003692:Delayed-Action Preparations / Q000737:chemistry / Q000493:pharmacokinetics; D005353:Fibronectins / Q000737:chemistry / Q000493:pharmacokinetics*; D019344:Lactic Acid / Q000737:chemistry / Q000493:pharmacokinetics; D018613:Microscopy, Confocal / Q000379:methods; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008863:Microspheres; D017830:Octoxynol; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry / Q000493:pharmacokinetics; D011100:Polyglycolic Acid / Q000737:chemistry / Q000493:pharmacokinetics; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry / Q000493:pharmacokinetics*; D011142:Polyvinyl Alcohol / Q000737:chemistry / Q000493:pharmacokinetics; D011487:Protein Conformation / Q000187:drug effects; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry / Q000493:pharmacokinetics; D013678:Technology, Pharmaceutical / Q000379:methods
D003692:Delayed-Action Preparations; D005353:Fibronectins; D011108:Polymers; D013501:Surface-Active Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D012710:Serum Albumin, Bovine; D019344:Lactic Acid; D011092:Polyethylene Glycols; D011142:Polyvinyl Alcohol; D017830:Octoxynol; C010615:Nonidet P-40