title: Biodegradable micro- and nanoparticles as long-term delivery vehicles for gentamicin.
abstract: Micro- and nanoparticles of poly(lactide-co-glycolide) (PLGA) loading gentamicin were prepared by a solvent evaporation method with the aim of obtaining appropriate vectors for systemic administration. Microspheres presented mean diameters below 3 microm and nanoparticles showed homogeneous sizes with a diameter of 320 nm. Drug loading was more efficient in the case of microencapsulation. The more hydrophilic copolymers with carboxyl-end groups yielded higher microparticle loadings, reaching encapsulation efficiencies up to 9.2 microg mg(-1) of polymer (502H, 503H or 75:25H). Nanoparticles made of 502H PLGA also achieved an acceptable level of encapsulation (6.2 microg mg(-1)). Particles prepared by using the solvent evaporation method showed no aggregation after hydration, in contrast to the microparticles prepared by spray-drying which showed fast and high auto-aggregation. In vitro release profiles revealed that 503H microspheres showed the highest burst during the first hour, while the most sustained release was for microparticles of 502H copolymer (40% of gentamicin remained in the formulation after 28 days). In summary, microspheres made of 502H, 503H and 75:25H and nanoparticles of 502H showed the best potential properties for systemic use in the treatment of intra-cellular gentamicin-susceptible pathogens.
authors.affiliation: Department of Microbiology, University of Navarra, Pamplona, Spain.
authors.forename: Concepcion
authors.initials: C
authors.lastname: Lecaroz
authors.forename: Carlos
authors.initials: C
authors.lastname: Gamazo
authors.forename: María Jesus
authors.initials: MJ
authors.lastname: Renedo
authors.forename: María J
authors.initials: MJ
authors.lastname: Blanco-Prieto
mesh_terms: D000372:Agglutination Tests; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001672:Biocompatible Materials / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D003692:Delayed-Action Preparations / Q000008:administration & dosage; D004339:Drug Compounding / Q000379:methods; D005839:Gentamicins / Q000008:administration & dosage*; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D014677:Pharmaceutical Vehicles; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D003692:Delayed-Action Preparations; D005839:Gentamicins; D014677:Pharmaceutical Vehicles; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid