A dry powder composition for preventing or treating influenza comprising a lactose hydrate diluent and (2R,3R,4S)-3-acetamido-4-guanidino-2-[(1R,2R)-2-hydroxy-1-methoxy-3-(octanoyloxy)propyl]-3,4-dihydro-2H-pyran-6-carboxylic acid
Disclosed is a dry powder pharmaceutical composition suitable for inhalation comprising (2R,3R,4S)-3-acetamido-4-guanidino-2-[(1R,2R)-2-hydroxy-1-methoxy-3-(octanoyloxy)propyl]-3,4-dihydro-2H-pyran-6-carboxylic acid (Formula (I)), and optionally (2R,3R,4S)-3-acetamido-4-guanidino-2-[(1S,2R)-3-hydroxy-1-methoxy-2-(octanoyloxy)propyl]-3,4-dihydro-2H-pyran-6-carboxylic acid (Formula (II)) with a lactose hydrate diluting agent, wherein the lactose hydrate has a particle distribution satisfying one of (Condition-1): the particle size distribution of the lactose hydrate measured by particle size analysis-laser diffraction methods has a 10 per cent by weight particle size of 5 microns to 60 microns, a 50 per cent by weight particle size of 50 microns to 110 microns, and a 90 per cent by weight particle size of 75 microns to 160 microns or (Condition-2): in the particle size distribution measured by an air entrainment method, a fraction with a particle size of less than 32 microns, a fraction with a particle size of less than 63 microns, a fraction with a particle size of less than 100 microns make up 5 to 10 per cent by weight, 70 to 100 per cent by weight, and100 per cent by weight, respectively and another lactose hydrate having a particle size distribution satisfying one of (Condition-3): the particle size distribution of the lactose hydrate measured by particle size analysis-laser diffraction methods has a 10 per cent by weight particle size of 3 microns or less, a 50 per cent by weight particle size of 20 microns or less, and a 90 per cent by weight particle size of 54 microns or less or (Condition-4): in the particle size distribution measured by an air entrainment method, a fraction with a particle size of less than 45 microns, a fraction with a particle size of less than 63 microns, and a fraction with a particle size of less than 150 microns make up 90 to 100% by weight, 98 to 100 per cent by weight, and 100 per cent by weight, respectively.
