Respiration triggered magnetic drug targeting in the lungs.
Lung cancer kills per year 1.3 million people worldwide. It is the most fatal cancer type as far as men are concerned and the second deadliest for women. One of the recent technologies to treat carcinomas in the lungs consists in delivering drugs through the pulmonary pathways directly to the tumor cells over actively loaded superparamagnetic nanoparticles that are encapsulated in aerosols and guided by external magnetic fields. However, first implementations of this technique assumed a continuous application of the magnetic field all through the inspiration and expiration phases of the artificial respiratory act that supplies the patient. We observed that applying the field this way forced the magnetic aerosols to sediment at regions far from the target, mainly in the trachea and main bronchioles, because of the force inducing magnetic field gradients that are present over the whole field application area. We developed an approach to avoid this effect by punctually generating the aerosol cloud exactly at the beginning of the inspiration phase, which would propel the particles to the deepest parts of the lung and therefore to the targeted cells as well, and by synchronizing the magnetic field activation with the breathing process. Our developed system analyzes the relevant respiration parameters such as pressure and flow and detects the end of the inspiration phase to trigger the magnet exactly at that point in time, when particles have reached the deepest alveoli, including the targeted zones, and do not experience forces due to the streaming any more. The magnetic field is then held on during the expiration phase to assure the retention of the aerosols at the targeted sites, which increases the efficiency and focality of the treatment. This way, only target cells are subjected to the deposition of the drug carrying aerosols, while the other healthy regions of the lungs remain unaltered by side effects.