title: Preparation and characterization of lung-targeting ceftiofur-loaded gelatin microspheres.
abstract: BACKGROUND
  Ceftiofur is an effective antibiotic against respiratory infections in livestock. However, ceftiofur concentration that is found in lungs after intravenous injection is not effective. Fortunately, ceftiofur-loaded gelatin microsphere (Cef-MS) enjoys advantages of lung-targeting and can achieve an effective concentration. However, no study has been reported on this modality of drug delivery.
  
  
  OBJECTIVE
  We investigated the properties of this delivery modality--lung targeting ceftiofur-Cef-MSs.
  
  
  METHODS
  We prepared Cef-MS and investigated drug loading, stability and release characteristics in vitro and studied tissue distribution patterns and potential lung injury in mice.
  
  
  RESULTS
  Results showed that the average size and span value are 21.26 μm and 1.07, respectively. Drug loading and loading efficiency were 15.31 and 76.55%, respectively. Cef-MSs were stable in light, heat and humidity, except that agglutinative phenomenon was observed in 90% humidity after 10 days. Cef-MS presented a slower in vitro release pattern compared to ceftiofur. Cef-MS mainly concentrates in lungs after intravenous administration. Furthermore, histopathological studies showed that Cef-MS only induces mild and reversible lung injury and is biologically safe.
  
  
  CONCLUSIONS
  Cef-MS is a promising alternative form with high lung-targeting properties for the treatment of respiratory infections.
authors.affiliation: Department of Pharmacology and Toxicology, College of Veterinary Medicine, China Agricultural University, Beijing, P.R. China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Hao
authors.forename: Baohan
authors.initials: B
authors.lastname: Qu
authors.forename: Yanling
authors.initials: Y
authors.lastname: Wang
authors.forename: Shusheng
authors.initials: S
authors.lastname: Tang
authors.forename: Gang
authors.initials: G
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Qiu
authors.forename: Ruili
authors.initials: R
authors.lastname: Zhang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.forename: Xilong
authors.initials: X
authors.lastname: Xiao
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D002511:Cephalosporins / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D004337:Drug Carriers / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D016503:Drug Delivery Systems / Q000379:methods*; D005260:Female; D005780:Gelatin / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D007275:Injections, Intravenous; D008168:Lung / Q000187:drug effects*; D008297:Male; D051379:Mice; D008863:Microspheres; D023421:Models, Animal; D010316:Particle Size
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D004337:Drug Carriers; C053503:ceftiofur; D005780:Gelatin