Optimum inspiratory conditions of targeting therapy of the upper airways for anti-influenza virus inhalers

Anti-influenza virus inhalers formulated as a dry powder have been applied clinically in the treatment of seasonal influenza, which is one of the upper respiratory tract infections. In this study, the optimum respiratory conditions were examined together with the degrees of suitable drug delivery efficiency to the the local upper airways, because the degree of efficiency varied as functions of the particle size distributions of inhaled drugs and the respiratory conditions. Dry powder inhalers, such as zanamivir hydrate and laninamivir octanoate hydrate, were used in the experiments. From the experimental results in the measurement of the inhaled particle size distributions and the analysis of the degree of drug delivery efficiency, the optimum degree of respiratory effect based on the efficiency findings was adequately obtained in patients breathing normally in a sitting position.