Ricin formulations

One sc formulation is capable of releasing sufficient amounts of ricin A-chain (RAC) to elicit IgG formation at protective levels over a period of 4-6 weeks. 

Two commercial vaccines based on virosome technology are currendy on the market. Epaxal (Berna Biotech Ltd, Bern, Switzerland), a hepatitis A vaccine, has inactivated hepatitis A virus particles adsorbed on the surface of the immunopotentiating reconstituted influenza virosomes (IRIV). In Inflexal V (Berna Biotech Ltd) the virosome components themselves are the vaccine protective antigens (185). Recently, in phase I study liposome-encapsulated malaria vaccine (containing monophosphoryl lipid A as adjuvant in the bilayer), the formulation showed induction of higher level of anti-malaria antibody in human volunteers (186). Some liposomal formulations are under investigation in preclinical studies against Yersina pestis, ricin toxin and Ebola Zaire virus (77, 187). 

Griffiths, G.D., Phillips, G.J. and Bailey, S.C. (1999) Comparison of the quality of protection elicited by toxoid and peptide liposomal vaccine formulations against ricin as assessed by markers of inflammation. Vaccine, 17, 2562-2568. 

Griffiths GD, Bailey SC, Hambrook JL et al. (1998). Local and systemic responses against ricin toxin promoted by toxoid or peptide vaccines alone or in liposomal formulations. Vaccine, 16, 530-535. 

Immunotoxins composed of ricin A chain coupled to a cell-specific monoclonal antibody have continued to show promise as a new class of antitumor agents. Gnt tin and Raso investigated the use of the carboxylic ionophor monensin formulated in an O/W emulsion for the in vitro and in vivo potentiation of immu-notoxin.s. Monensin in this pharmacologically available form significantly improved the in vivo efficacy of both anti-human transferrin receptor immunotoxin and anticarcinoembryonic antigen immunotoxin when used as regional therapy. 

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