Liposomes according to the present invention for a pulmonary administration,advantageously comprising at least a first and at least a second phospholipidas well ascholesterol and at least one active compound and/or dye, whereby the firstphospholipid isa phosphatidylcholine, preferably DSPC, and the second phospholipid is aphosphatidylcholine or an ethanolamine, preferably chosen from the group ofDMPC,DPPC, DPPE. It is favorable if the first and the second phospholipid arepresent in a molarratio ranging from 0.5:1 to 10:1, preferred in a molar ratio of 6:1 to 2:1,particularlypreferred is a molar ratio of 3:1. In addition favorable is if the molar ratioof phospholipidsto cholesterol ranges between 10:1 and 1:1, preferably between 6:1 and 3:1,particularlypreferred is a molar ratio of 4:1. Furthermore evident is that the secondphospholipid ispreferably DMPC or DPPE, particularly preferred DPPE. The size of theliposomesadvantageously ranges between 0.05 µm and 5 µm, preferred between 0.2µm and2.0 µm, and the mass median aerodynamic diameter of aerosol particles whichcontainthe liposomes is between 1 µm and 6 µm, preferred between 1.5 µm and5 µm,particularly preferred between 2 µm and 4.5 µm. Particularlyadvantageous is also if thestability of liposomes during nebulization is higher than 50 %, preferredhigher than 75 %,particularly preferred higher than 80 %. Furthermore advantageous is if thephasetransition temperature is higher than 37°C, preferred higher than45°C, and particularlypreferred higher than 50°C.
