TRANSFERSOMES FOR VACCINE DELIVERY: A POTENTIAL APPROACH FOR TOPICAL IMMUNIZATION

Abstract

Delivery of vaccine is a major impediment to ensuring vaccine efficacy and compliance. Existing vaccine delivery approaches have their limitations and these led to the development of novel approaches for vaccine delivery. Non-invasive vaccine delivery is in demand and for this skin appears to be a potential sites that elicit immune responses. Topical application of antigen and adjuvant directly on the skin is termed as topical vaccination. It has potential to reduce physical skin penetration by injection and provide potentially effective vaccines. In the present study novel carrier, transfersomes were used for topical delivery of tetanus toxoid (TT). Transfersomes were prepared by reverse phase evaporation method and they were evaluated for shape, size, entrapment efficiency and deformability index. Transfersomal formulation with optimal concentration of Soya phosphatidylcholine (SPC) and sodium deoxycholate (85:15 w/w) showed entrapment efficiency of 39.8±0.032 and deformability index of 16.4. In-vivo study revealed that topically given TT containing transfersomes after boosting produced immune responses (0.877±0.081) that is as good as that produced by subcutaneously given alum adsorbed TT (0.948±0.088). Furthermore, fluorescence microscopy has confirmed the bioactive delivery through the skin layers. A brief comparative study has been done with liposomes.