title: Local, Controlled Delivery of Local Anesthetics In Vivo from Polymer - Xerogel Composites.
abstract: OBJECTIVE
  Polymer-xerogel composite materials have been introduced to better optimize local anesthetics release kinetics for the pain management. In a previous study, it was shown that by adjusting various compositional and nano-structural properties of both inorganic xerogels and polymers, zero-order release kinetics over 7 days can be achieved in vitro. In this study, in vitro release properties are confirmed in vivo using a model that tests for actual functionality of the released local anesthetics.
  
  
  METHODS
  Composite materials made with tyrosine-polyethylene glycol(PEG)-derived poly(ether carbonate) copolymers and silica-based sol-gel (xerogel) were synthesized. The in vivo release from the composite controlled release materials was demonstrated by local anesthetics delivery in a rat incisional pain model.
  
  
  RESULTS
  The tactile allodynia resulting from incision was significantly attenuated in rats receiving drug-containing composites compared with the control and sham groups for the duration during which natural healing had not yet taken place. The concentration of drug (bupivacaine) in blood is dose dependent and maintained stable up to 120 h post-surgery, the longest time point measured.
  
  
  CONCLUSIONS
  These in vivo studies show that polymer-xerogel composite materials with controlled release properties represent a promising class of controlled release materials for pain management.
authors.affiliation: Center for Bioactive Materials and Tissue Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA.
authors.forename: Haibo
authors.initials: H
authors.lastname: Qu
authors.affiliation: New Jersey Center for Biomaterials, Rutgers, The State University of New Jersey, Piscataway, New Jersey, 08854, USA.
authors.forename: Marius C
authors.initials: MC
authors.lastname: Costache
authors.affiliation: Department of Pharmacology, Temple University, Philadelphia, Pennsylvania, 19140, USA.
authors.forename: Saadet
authors.initials: S
authors.lastname: Inan
authors.affiliation: Department of Pharmacology, Temple University, Philadelphia, Pennsylvania, 19140, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Cowan
authors.affiliation: U.S. Army Institute of Surgical Research, Fort Sam Houston, Texas, 78234, USA.
authors.forename: David
authors.initials: D
authors.lastname: Devore
authors.affiliation: Center for Bioactive Materials and Tissue Engineering, Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA. ducheyne@seas.upenn.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Ducheyne
mesh_terms: D000779:Anesthetics, Local / Q000737:chemistry*; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D002045:Bupivacaine / Q000737:chemistry*; D002254:Carbonates / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D016503:Drug Delivery Systems / Q000379:methods; D005782:Gels / Q000737:chemistry*; D007700:Kinetics; D008297:Male; D008422:Materials Testing / Q000379:methods; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012822:Silicon Dioxide / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000779:Anesthetics, Local; D001672:Biocompatible Materials; D002254:Carbonates; D004337:Drug Carriers; D005782:Gels; D011108:Polymers; D011092:Polyethylene Glycols; D014443:Tyrosine; D012822:Silicon Dioxide; D002045:Bupivacaine
keywords: composite; controlled release; local anesthetic; sol–gel