Mei Qiu

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

Pharmacokinetics of pidotimod in broiler chickens by UHPLC-MS/MS after oral and intravenous administration

Pidotimod is widely used in children as an immune promoter but it has not been fully evaluated in animals. The pharmacokinetics of pidotimod and its oral bioavailability have not been described in broiler chickens. We developed a simple and sensitive UHPLC-MS/MS assay for rapid determination of pidotimod levels in chicken blood. Recoveries were nearly 100% and the coefficients of accuracy and precision were minimal. Healthy broiler chickens were given 10 mg/kg pidotimod either orally or intravenously. The oral pidotimod was rapidly absorbed (time to reach maximum concentration, 1.25 h) and rapidly eliminated (the mean residence time was 3.2 h). A noncompartmental analysis of the intravenous route indicated a mean plasma clearance of 2.2 L (h kg)-1 with an estimated mean volume of distribution at steady state of 12.69 L/kg. The bioavailability of pidotimod after oral dosing was 27%.

Preparation and characterization of three types of cefquinome-loaded microspheres

ABSTRACT The polymers of poly (lactic-co-glycolic acid), gelatin, and ethyl cellulose were used to control the microscopic structure of microspheres prepared by spray drying. We investigated controlled release by varying material concentrations, sprayer inlet temperatures and air velocities, and optimized process parameters of yield, particle size, and distribution. Three types of polymeric microspheres with a mean particle size range of 13–25 µm were loaded with cefquinome and characterized. In vitro drug release studies determined that microspheres were the most suitable structures for controlling release due to their high entrapment capacities and release times greater than 24 h.

Effects of pidotimod soluble powder and immune enhancement of Newcastle disease vaccine in chickens

The aims of this study were to prepare pidotimod (PDM) soluble powder and to investigate the immune enhancement properties of PDM in chickens vaccinated with Newcastle disease virus vaccine. In vivo experiment, 360 6-day-old chickens were averagely divided into 6 groups. The chickens, except blank control (BC) group, were vaccinated with Newcastle disease vaccine (NDV). At the same time of the vaccination, the chickens in three PDM groups were given water with PDM for 5days, respectively, with the PDM at low, medium and high concentrations (0.25g/L, 0.5g/L, 1g/L), in control drug group was treated with 0.2ml/PDM dose via drinking water, in vaccination control (VC) and BC group, with equal volume physiological saline, once a day for five successive days. On days 14, 21 and 28 after the vaccination, the growth performance, the lymphocyte proliferation, serum antibody titer, the CD4/CD8 cell ratios and interleukin-2 (IL-2) and interferon-gamma (IFN-γ) were measured. The results showed that PDM at suitable dose could significantly promote growth performance, lymphocyte proliferation, enhance serum antibody titer, CD4/CD8 cell ratios and improve serum IL-2 and IFN-γ concentrations. It indicated that PDM could significantly improve the immune efficacy of Newcastle disease vaccine using doses of 0.5g/L, these results are consistent with the drug acting as an immunopotentiator.