ABSTRACT
Drug delivery via mucosal routes has been confirmed to be effective in inducing strong immune responses. Liposomes could enhance immune responses and mucoadhesive potentials, make them useful mucosal drug delivery systems. Coating of liposomes by mucoadhesive polymers succeeded in enhancing immune responses. Our studies aim at preparation and characterization of trimethylchitosan-coated nanoliposomes for nasal delivery of a model antigen, tetanus toxoid [TT]. Anionic liposomes were prepared by dehydration-rehydration method with an average size of 100 nm and were coated with 0.01% [w/v] solution of trimethyulchitosan [TMC] with 50 +/- 10% of quaternization. Surface properties and zeta potential were evaluated by DLS. Antigen stability and integrity were studied by SDS-PAGE electrophoresis. Nasal clearance rate and mucoadhesive properties of liposomes were studied by gamma scintigraphy method using 99mTc-labelled liposomes. The zeta potential of non-coated and TMC-coated liposomes was -40 and +38.8, respectively. Encapsulation rate of tetanus toxoid was 77 +/- 5.5%. SDS-PAGE revealed that the antigens remained intact during formulation procedure. Gamma scintigraphy confirmed that both types of liposomes could remain in nasal cavity up to ten folds over the normal residence time for conventional nasal formulations. TMC-coated nanoliposomes have several positive potentials including good mucoadhesive properties, preserved integrity of loaded antigen and presence of TMC as a mucoadhesive polymer with innate immunoadjuvant potential which make them suitable for efficient adjuvant/delivery system
Subject(s)
Animals , Adhesives , Chitosan , Polymers , Drug Delivery Systems , Tetanus Toxoid , RabbitsABSTRACT
Bacterial biofilm has been considered responsible for many deaths and high health costs worldwide. Their better protection against antibacterial agents compared to free living cells leads to poor treatment efficiency. Nanotechnology is promising approach to combat biofilm infections. The aim of the present study was to eradicate Staphylococcus epidermidis biofilm with silver nanoparticles [SNPs]. SNPs were used at different concentrations [two fold dilutions] and incubation times [24, 48, 72 h]. The crystal violet staining and pour plate assays were used to assess biofilm biomass and bacterial viability, respectively. The ability of SNPs on biofilm matrix eradication was assessed through optical density ratio [ODr]. Positive control was defined as an ODr =1.0. The crystal violet assay indicated that the biofilm matrixes were intact at different concentrations of SNOs and incubation times. There were no significant differences between these parameters [P >0.05]. Bacterial enumeration studies revealed that higher concentrations of SNPs were more effective in killing bacteria than lower ones. Although, longer incubation times led to enhancement of anti-biofilm activity of SNPs. The anti-biofilm activity of SNPs was concentration- and time-dependent. The results of this study highlighted that SNPs were effective against cell viability; however they were ineffective against biomass