Inhalation therapy is a widely used form of treatment for lung diseases such as asthma and COPD. However, various factors determine whether drugs are delivered effectively via an inhaler. For example, using one particular inhaler in a damp bathroom environment can double the amount of medication it dispenses, and new inhalation technology is clearing the way for a return to inhalable insulin and the possibility of administering anti-TB drugs and vaccines via the airways. Bart Rottier, paediatric respiratory specialist in the University Medical Center Groningen, studied ways of delivering medication to and via the airways, and concluded that the technique could be much more effective. Rottier will be awarded a PhD for the results of his research by the University of Groningen on 28 November 2012.
Although inhaling drugs can be more effective than administering them orally or via an injection, the effectiveness of this method depends on several factors, including the way the disease presents, the shape of the lungs, the particle size distribution of the drug and the inhalation technique. After studying the effectiveness of various inhaler systems, Rottier concluded that the choice of inhaler, including the choice of actuator with a specific type of inhaler (the metered-dose aerosol with spacer), is decisive in the amount of drug particles dispensed. External factors, such as humidity, can be important here. In addition, good communication between medical practitioner and patient is essential to ensure that the appliance is prepared and used correctly, and to stress the importance of the cleaning procedure.
Metered-dose aerosols are usually dispensed via an actuator, a plastic reservoir fitted between the inhaler and the mouth to allow slow and gradual inhalation of the medicine. Rottier studied the influence of a number of variables, such as the speed of inhalation from the actuator, the length of time between the dose being released into the actuator and it being inhaled, and the relative humidity of the environment. One of the most significant findings was that increasing the relative humidity can double the amount of medicine delivered by the inhaler. A logical piece of practical advice to asthma patients would therefore be to use metered-dose aerosol inhalers with a spacer in a damp bathroom to increase their effectiveness.
New areas for administering other drugs via the airways are also being explored: they include medicines for TB, vaccines and insulin for diabetes mellitus. A dry powder inhaler (the Exubera), used for delivering insulin, was withdrawn from the market just a year after it was introduced. High costs were among the reasons. One of the tasks Rottier set himself in his research was to compare the effect of drug delivery via the Exubera with that of the Twincer, a new inhaler developed by the Pharmaceutical Technology and Biopharmacy Department at the University of Groningen. His research showed that the Twincer was able to produce the same insulin levels as the Exubera, using half the amount of insulin. In addition, the Twincer delivers the full dose in the first phase of inhalation, which means that the drug is able to penetrate the deepest airways. According to Rottier, the results are not only promising in terms of reinstating inhalable insulin, but more importantly, also for dispensing other drugs via the airways to treat TB, for example, or to give vaccines.
Rottier also looked into how two types of nebulising systems reacted when used by adults with cystic fibrosis to inhale antibiotics on a daily basis for a period of six months. Despite advice to the contrary, patients used the same system to administer other drugs and did not clean a particular part of the system (the droplet-forming membrane: the mesh) according to the instructions. Blockages in some of the holes in the mesh ultimately prevented the nebulizer from dispensing the full dose of the drug. This led Rottier to conclude that although it is important that medical practitioners communicate with patients, this does not always guarantee that the patient will follow the instructions.
Bart Rottier (Amsterdam, 1965) studied Medicine at the VU University Amsterdam. He conducted his research at the Groningen Research Institute for Asthma and COPD (GRIAC), in close collaboration with the Paediatric Respiratory Department of the Beatrix Children’s Hospital at the UMCG and the Pharmaceutical Technology and Biopharmacy Department of the Faculty of Mathematics and Natural Sciences at the University of Groningen. His thesis is entitled ‘Improving the drug delivery to the lungs.’
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