Preparation and pharmacokinetics of ceftiofur sodium liposomes in cows.

The objective of this study was to prepare ceftiofur sodium liposomes and assess their physical properties, stability, antibacterial effects, and pharmacokinetics. These liposomes appeared as a milky, light yellow suspension with encapsulation efficiency at 57.2 ± 1.17%, and there were no significant changes in all estimated indexes at 4 °C for 90 days. The minimum inhibitory concentrations of liposomes were all 1/4th that of ceftiofur sodium against Streptococcus suis, Staphylococcus aureus, Escherichia coli, and Salmonella enteritidis. Six healthy, adult cows in two treatment groups were dosed intravenously with ceftiofur sodium liposomes and ceftiofur sodium, serial blood samples collected, and plasma concentrations determined by high performance liquid chromatography. Intravenous plasma concentration profiles of liposomes best fit a two-compartment model and the elimination half-life was 2.11 times that of ceftiofur sodium. Thus, this liposome preparation provided therapeutically effective plasma concentrations for a longer duration than with the drug alone, making it more effective and convenient for use in treating bovine mastitis that requires long duration maintenance of therapeutic plasma concentrations.