Pressurized packs containing a phospholipid and drug that permits in situ formation of liposomes following deposition of the aerosolized cloud in the respiratory tract have been investigated. Prepared pressure packs and preformed liposomes of different lipoidal contents were characterized for shape, size, lamellarity and percentage drug entrapment. Pressure packs were studied for airway penetration efficiency. The study revealed that pressure packs-derived liposomes containing isoprenaline were fairly comparable with preformed liposomes by the ether injection method. The liposomal charge was found to effect drug disposition. However, drug sustained action was recorded in the case of liposomal inhalation(s) as compared to plain drug inhalation. The pressure packs thus demonstrated therapeutic potentiality in lung targeting of isoprenaline, as well as avoiding the liposome stability problem.