Preparation and in vitro evaluation of a novel chitosan-based hydrogel for injectable delivery of enrofloxacin

Background: the development of injectable sustained- release products are of great interest to veterinary pharmaceuticals and animal health business. Recently, great attention has been paid to in situ gel-forming chitosan/ beta-glycerophosphate [chitosan/beta-GP] solutions due to their good biodegradability and thermosensitivity

Objectives: the general aim of this study was to prepare a novel in situ gel-forming drug delivery system with a sustained release profile for enrofloxacin

Methods: chitosan, beta-GP and enrofloxacin were used in different concentrations and six formulations of chitosan/beta-GP were prepared. The properties of the hydrogels including the pattern of drug release, gelation time, syringeability, morphology, FTIR spectra, and in vitro antimicrobial activity were evaluated

Results: the release rate of enrofloxacin from the hydrogels and syringeability of the final solutions were decreased by increasing in beta-GP and chitosan concentrations. All formulations could release the drug up to 120 hours but formulation 1 [chitosan-2%, beta-GP-5% and enrofloxacin-1%] gave the best results based on its optimal drug release profile and viscosity. The FTIR studies showed that there were no interactions between enrofloxacin and hydrogel excipients. Scanning electron microscopy showed that the formed gel had a continuous texture, while the swelled gel in phosphate buffer had a porous structure. Microbiological tests revealed high bactericidal activities for this enrofloxacin- loaded hydrogel which were comparable to those of positive control [enrofloxacin suspension] in terms of inhibition zone, MIC and MBC values

Conclusions: because of simple preparation and sustained release profile of the drug, this hydrogel could be a promising delivery system for enrofloxacin in animals

Preparation and evaluation of a thermosensitive liposomal hydrogel for sustained delivery of danofloxacin using mesoporous silica nanoparticles

Background: sustained release delivery system can reduce the dosage frequency and maintain the therapeutic level of drugs for a longer time. Biodegradable, biocompatible and thermosensitive chitosan-beta-glycerophosphate [C-GP] solutions can solidify at body temperature and maintain their physical integrity for a longer duration

Objectives: to develop a novel delivery system based on the integration of liposomes in hydrogel using mesoporous silica nanoparticles [MSNs] for sustained release of danofloxacin in farm animals

Methods: the MSNs were prepared using N-cetyltrimethylammonium bromide and tetraethylortho silica. The liposomes were prepared by thin film hydration method. C-GP solution containing danofloxacin-loaded MSN liposomes underwent different in-vitro tests, including evaluation of the entrapment efficiency, gelation time, morphology, drug release pattern as well as antimicrobial activities against S. aureus and E. coli

Results: the mean pore size of MSNs was 2.8 nm and the mean MSN entrapment efficiency was 45%. Kinetics of danofloxacin release from liposomal hydrogel followed the Higuchi's model. This formulation was capable of sustaining the danofloxacin release for more than 96 h. The FTIR studies showed that there were no interactions between danofloxacin and hydrogel excipients. Scanning electron microscopy [SEM] showed that the formed gel had a continuous texture, while the swelled gel in the phosphate buffer had a porous structure. Microbiological tests revealed a high antibacterial activity for lipomosal hydrogel of danofloxacin-loaded MSN comparable with danofloxacin solution

Conclusions: the liposomal hydrogel solidified at body temperature, effectively sustained the release of danofloxacin and showed in vitro antibacterial effects

Leucocytozoonosis in domestic birds in southwestern Iran: an ultrastructural study

Leucocytozoonosis is a disease of birds caused by obligate intracellular protozoa of the genus Leucoytozoon. We determined the prevalence of Leucocytozoon spp. using light and transmission electron microscopy in domestic birds in southwest of Iran. A total of 825 blood smears from 275 birds were examined for presence of infection. The structure morphology of "Leucocytozoon spp. was studied using light and electron microscopy. Forty-four [16.0%] of the birds were positives for Leucocytozoon. The detected parasite were found in 14 chickens [5.1%], 12 geese [4.3%], 10 ducks [3.6%], and 8 turkeys [2.9%]. The majority of the records were from the northeastern regions. Leucocytozoonosis are distributed in the Lorestan province bird population and electron microscopy can resolve the problem to distinguish between similar species of Leucocytozoon