A comparative study of niosomal and elastic niosomal carbomer hydrogel for transcutaneous vaccine delivery

Transcutaneous immunization is becoming an attractive non-invasive vaccination strategy, though it is still challenging. This study evaluates the potential of transcutaneous delivery of antigens in mice through niosomal and elastic niosomal carbomer hydrogels. Ovalbumin was encapsulated into niosomes prepared by Span 80/cholesterol/stearylamine through reverse-phase evaporation. Ethanol was added into niosomal mixtures for elastic niosomes formation, then embedded in carbopol 934 hydrogel. Encapsulation efficiency and other physiochemical properties of the prepared niosomal vesicles such as particle size, stability, in vitro release and cytotoxicity were determined. In vivo immunizations of niosomal and elastic niosomal gel were carried out in mice. The optimal niosomal formulation loads 48.6 ± 5.2% ovalbumin with a vesicle size below 300 nm. A simple BCA method was used to determine the encapsulation efficiency of niosome. The cumulative permeation of proteins of niosomal gel was 15~20%. Both gels were stable at room temperature; however, elastic niosomal gel deteriorated at 60 ℃. Compared to free antigen, the topical administration of niosomal or elastic niosomal gel to mice displayed significant IgG titers. From the findings, compared to elastic niosomal gel, the niosomal hydrogel platform exhibited enhanced antigen delivery. Therefore, niosomal hydrogel may be considered a promising transcutaneous antigen delivery carrier.