Physical stability of coconut oil lotions formulated using hydrophile-lipophile balance system of various emulsifier pairs.

The aim of this study was to prepare coconut oil lotions using a hydrophile-lipophile balance system to calculate the proportion of each nonionic surfactant used. The effects of emulsifier pairs in the formulations on physical properties (i.e., appearance, emulsion type, pH, flow type, viscosity) were investigated. The physical stability of the lotions was determined at ambient temperature (approximatley 30 degrees C) after the lotions were kept for 30 as well as 60 days and in accelerated conditions (6 freeze-thaw cycles). It was found that the formulations most tolerant to such harsh conditions were F1 and F2, o/w lotions containing 40% w/w coconut oil, 50% w/w water and 10% w/w of the mixed emulsifier of a low hydrophile-lipophile balance surfactant (sorbitan monostearate) and a high hydrophile-lipophile balance surfactant (either polyoxyethylene [20] sorbitan monooleate or polyethylene [20] sorbitan monolaurate).

Development and evaluation of chitosan-coated liposomes for oral DNA vaccine: the improvement of Peyer's patch targeting using a polyplex-loaded liposomes.

The aim of this study was to develop chitosan-coated and polyplex-loaded liposomes (PLLs) containing DNA vaccine for Peyer's patch targeting. Plain liposomes carrying plasmid pRc/CMV-HBs were prepared by the reverse-phase evaporation method. Chitosan coating was carried out by incubation of the liposomal suspensions with chitosan solution. Main lipid components of liposomes were phosphatidylcholine/cholesterol. Sodium deoxycholate and dicetyl phosphate were used as negative charge inducers. The zeta potentials of plain liposomes were strongly affected by the pH of the medium. Coating with chitosan variably increased the surface charges of the liposomes. To increase the zeta potential and stability of the liposome, chitosan was also used as a DNA condensing agent to form a polyplex. The PLLs were coated with chitosan solution. In vivo study of PLLs was carried out in comparison with chitosan-coated liposomes using plasmid encoding green fluorescence protein as a reporter. A single dose of plasmid equal to 100 µg was intragastrically inoculated into BALB/c mice. The expression of green fluorescence protein (GFP) was detected after 24 h using a confocal laser scanning microscope. The signal of GFP was obtained from positively charged chitosan-coated liposomes but found only at the upper part of duodenum. With chitosan-coated PLL540, the signal of GFP was found throughout the intestine. Chitosan-coated PLL demonstrated a higher potential to deliver the DNA to the distal intestine than the chitosan-coated liposomes due to the increase in permanent positive surface charges and the decreased enzymatic degradation.

Heterosubtypic immunity to influenza mediated by liposome adjuvanted H5N1 recombinant protein vaccines.

A non-egg, non-culture based influenza vaccine that intervenes large influenza outbreaks and protects against heterosubtypic infections is needed. Candidates of such vaccine are likely to be conserved influenza virus proteins or their coding DNA. The vaccine must be conveniently produced at reasonable cost, safe, highly immunogenic and should be able to recall rapidly the immunological memory upon the antigenic re-exposure. In this study vaccines made of full length recombinant NP and M2 of the H5N1 influenza A virus were entrapped either alone or together into liposome (L) made of phosphatidylcholine and cholesterol. The vaccines (L-NP, L-M2 or L-NP+M2) and mocks (L or PBS) were safe without causing any adverse reaction in the intramuscularly injected mice. They were readily immunogenic at a single dose and a recalled response could be detected within one day post booster. Cytokine and antibody data indicated that the vaccines induced a Th1 bias immune response. NP containing vaccines stimulated a marked increase of cytotoxic lymphocytes, i.e., CD8(+), intracellular IFNγ(+) cells, while M2 containing vaccines elicited good antibody response which neutralized infectivity of heterologous influenza viruses. Although the three vaccines elicited different immunological defense factors; nevertheless, they similarly and readily abrogated lung histopathology mediated by viruses belonging to different H5N1 clade/subclade and heterosubtypes including swine H1N1 and human H1N1/2009 viruses. They protected the vaccinated mice against lethal challenges with mouse adapted avian H5N1 virus. The liposome adjuvanted vaccines which demonstrated high protective efficacy in mice warrant testing further in a non-rodent model as well as in humans.

Cloning, protein expression and immunogenicity of HBs-murine IL-18 fusion DNA vaccine.

Hepatitis B is a global serious disease caused by hepatitis B virus (HBV). There is no known cure for hepatitis B. The best way to deal with the disease is by preventing with hepatitis B vaccine. However, the current protein-based vaccines made up of recombinant hepatitis B surface antigen (HBsAg) are ineffective in chronic HBV carriers and a significant number of the vaccinees do not mount the protective immune response. Novel DNA-based immunization may overcome the deficits of the protein-based immunization and may provide more effective prophylactic and therapeutic outcomes. In this study, we constructed a recombinant plasmid carrying gene encoding the HBV surface antigen (HBs) linked to DNA segment encoding full-length murine interleukin-18, i.e. pcDNA-HBs-IL-18. Immunogenicity of the DNA construct was carried out in BALB/c mice in comparison with mock, i.e. pcDNA3.1+ and vaccines comprised of pRc/CMV-HBs and pRc/CMV-HBs plus pcDNA-IL-18. All vaccinated mice revealed significant serum anti-HBs IgG response after two intramuscular injections of the vaccines at 28 day interval as compared to the level of mock. Co-administration of pRc/CMV-HBs and pcDNA-IL-18 elicited arbitrarily higher levels of anti-HBs IgG than the levels in mice immunized with pRc/CMV-HBs alone and mice that received pcDNA-HBs-IL-18 although not statistically different. Further experiments are needed to investigate the subisotypes of the IgG antibody, the kinetics of cytokine and the cell-mediated immune response. For this communication, the prototype HBs-IL-18 DNA vaccine was successfully constructed and the gene encoding murine IL-18 was successfully cloned. The latter can be co-injected with the antigen coding DNA or used as a fusion partner to the DNA for priming the immune response. The recombinant HBs and full-length IL-18 proteins have potential for other research purposes. They may be used also as standard proteins in the protein quantification assay.