Feasibility Study of Inhaled Hepatitis B Vaccine Formulated with Tetradecylmaltoside

This study was designed to test the hypothesis that formulation of hepatitis B vaccine with tetradecyl-beta-maltoside (TDM) enhances the immune response after pulmonary administration in a rodent model. Commercially available recombinant hepatitis B vaccine (rHBV) was formulated with varying concentrations of TDM and administered intratracheally to anesthetized male Sprague-Dawley rats. rHBV administered intramuscularly at doses of 2 and 4 microg served as positive controls. All formulations were administered on days 0 and 14 and the immune response was evaluated for 28 days. Specific antibodies generated to HBsAg were analyzed by ELISA. Safety studies were carried out by measuring the levels of alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and tumor necrosis factor alpha (TNF-alpha) in bronchoalveolar lavage (BAL) fluid. There was a significant increase in the immune response when the vaccine was administered intramuscularly at a dose of 4 microg. Only a modest increase in the immune response was observed when plain rHBV was administered intratracheally at the same dose. However, a pulmonary formulation of 4 microg rHBV plus 0.5% TDM produced a fourfold increase in the immune response compared to plain rHBV administered via the pulmonary route. No increase in immune response was observed for formulations containing rHBV plus 0.125% or 0.25% TDM. The levels of ALP and LDH in the BAL fluid suggest that the hepatitis B vaccine plus TDM formulations cause some injury to the lungs after the first intratracheal instillation of the formulation; however, the enzyme levels tended to be lower after the second instillation. The level of TNF-alpha in the BAL fluid of TDM-treated rats was substantially lower than that in rats treated with the positive control substance, sodium dodecyl sulfate. Overall, rHBV formulated with TDM increases the immune response after pulmonary administration, and pulmonary formulation of rHBV plus TDM could be used as an alternative to needle-based delivery of hepatitis B vaccine.