Dry powder inhaler for delivering multipe agglomerate formulations

A dry powder inhaler for dispensing inhaled doses of dry powder, the dry powder inhaler comprising:

• a de-agglomeration chamber having at least one exit opening, a first inlet opening and a second inlet opening, said at least one exit opening, said first inlet opening and said second inlet opening being arranged such that, upon inhalation of a dose, negative pressure is applied to said at least one exit opening which causes a first stream of dry powder to be entrained from said first inlet opening into said de-agglomeration chamber directed toward said at least one exit opening, said negative pressure also causing a second stream of dry powder to be entrained from said second inlet opening into said de-agglomeration chamber directed toward said at least one exit opening, said first and second streams of dry powder colliding in said de-agglomeration chamber to form a collective stream passing through said exit opening;
• and,
• at least one by-pass channel disposed adjacent to, and separated from, said de-agglomeration chamber, said at least one by-pass channel having an inlet and an outlet, wherein, upon inhalation of a dose, negative pressure is applied to said outlet which causes a third stream of dry powder to be entrained from said inlet directed toward said outlet, said third stream of dry powder not passing through any portion of said de-agglomeration chamber.