title: Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes.
abstract: Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH(2)Cl(2) (organic):PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery.
authors.affiliation: College of Chemistry, University of California, Berkeley, California 94720-1460, United States.
authors.forename: Cátia
authors.initials: C
authors.lastname: Ornelas-Megiatto
authors.forename: Parth N
authors.initials: PN
authors.lastname: Shah
authors.forename: Peter R
authors.initials: PR
authors.lastname: Wich
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Cohen
authors.forename: Jasur A
authors.initials: JA
authors.lastname: Tagaev
authors.forename: Justin A
authors.initials: JA
authors.lastname: Smolen
authors.forename: Brian D
authors.initials: BD
authors.lastname: Wright
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Panzner
authors.forename: Wiley J
authors.initials: WJ
authors.lastname: Youngs
authors.forename: Jean M J
authors.initials: JM
authors.lastname: Fréchet
authors.forename: Carolyn L
authors.initials: CL
authors.lastname: Cannon
mesh_terms: D000280:Administration, Inhalation; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003911:Dextrans / Q000008:administration & dosage*; D004337:Drug Carriers; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000008:administration & dosage; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012834:Silver / Q000737:chemistry* / Q000378:metabolism; D012995:Solubility; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000890:Anti-Infective Agents; D003911:Dextrans; D004337:Drug Carriers; D004364:Pharmaceutical Preparations; C030011:carbene; D012834:Silver; D008697:Methane