The present invention provides an inhalation device for controlled delivery of medicament to the lungs of the user. The inhalation device comprises an elongated housing enclosing a mouthpiece/nasal-piece in fluid communication to a narrow cylindrical tube, the narrow cylindrical tube having diameter substantially similar to the lumen diameter of human bronchi. The other end of narrow cylindrical tube is fluidly connected to a reservoir containing the medicament suspended or dissolved in the propellant. The flow of propellant from reservoir to the narrow cylindrical tube is regulated by a one-way valve, which could be electrical/electronic or a mechanical valve. The invention is advantageous by providing positive airway pressure to keep the constricted air passages of the user open, which is combined, with laminar flow of medicament suspended/dissolved in the propellant, thus, resulting in efficient deposition of medicament to the target tissues of the lungs.