Preparation and characterization of lung-targeting ceftiofur-loaded gelatin microspheres.

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 mu m 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. Conclusion: Cef-MS is a promising alternative form with high lung-targeting properties for the treatment of respiratory infections.