Compositions, methods and systems are provided for pulmonary or nasal delivery of active agents via a metered dose inhaler. In one embodiment, the compositions include a suspension medium, active agent particles, and suspending particles, in which the active agent particles and suspending particles form a co-suspension within the suspension medium.本發明提供通過定劑量吸入器經由肺或鼻輸送活性劑的組成物、方法與系統。在一個具體例中,組成物包括懸浮介質、活性劑粒子及懸浮粒子,其中活性劑粒子及懸浮粒子在懸浮介質內形成共懸浮液。