title: In vitro and in vivo performance of dexamethasone loaded PLGA microspheres prepared using polymer blends.
abstract: The foreign body reaction is the major cause of the dysfunction and relatively short lifetime associated with implanted glucose biosensors. An effective strategy to maintain sensor functionality is to apply biocompatible coatings that elute drug to counter the negative tissue reactions. This has been achieved using dexamethasone releasing poly(lactic-co-glycolic acid) (PLGA) microspheres embedded in a polyvinyl alcohol (PVA) hydrogel coating. Accordingly, the biosensor lifetime relies on the duration and dose of drug release from the coating. To achieve long-term drug release mixed populations of microspheres have been used. In the current study, microspheres were prepared by blending low (25KDa) and high (113KDa) molecular weight PLGA at different mass ratios to overcome problems associated with mixing multiple populations of microspheres. "Real-time" in vitro studies demonstrated dexamethasone release for approximately 5 months. An accelerated method with discriminatory ability was developed to shorten drug release to less than 2 weeks. An in vivo pharmacodynamics study demonstrated efficacy against the foreign body reaction for 4.5 months. Such composite coatings composed of PLGA microspheres prepared using polymer blends could potentially be used to ensure long-term performance of glucose sensors.
authors.affiliation: University of Connecticut, School of Pharmacy, Storrs, CT 06269, USA.
authors.forename: Bing
authors.initials: B
authors.lastname: Gu
authors.affiliation: University of Connecticut, School of Pharmacy, Storrs, CT 06269, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: University of Connecticut, School of Pharmacy, Storrs, CT 06269, USA. Electronic address: d.burgess@uconn.edu.
authors.forename: Diane J
authors.initials: DJ
authors.lastname: Burgess
mesh_terms: D015374:Biosensing Techniques; D003907:Dexamethasone / Q000737:chemistry*; D005947:Glucose / Q000032:analysis*; D019344:Lactic Acid / Q000737:chemistry*; D008863:Microspheres; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011142:Polyvinyl Alcohol / Q000737:chemistry; D012995:Solubility
chemical_list: C062364:polyvinyl alcohol hydrogel; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D003907:Dexamethasone; D011142:Polyvinyl Alcohol; D005947:Glucose
keywords: Accelerated release testing; Foreign body reaction; Glucose biosensors; Long-term drug release; Microspheres; PLGA; Polymer blends