Inhalation therapy devices

The concept of the L T ratio in inhalation therapy is a useful one, where L represents the local or lung availability of an inhaled drug and T the total systemic availability. This ratio will be affected by differences in first-pass metabolism. Another important variable that determines the L T ratio is the inhalation device. The L T ratio for budesonide is 0.66-0.85, depending on the method of inhalation (12). 

The Easyhaler (by Orion Pharma, Finland) and the Clickhaler (by Innovata pic, United Kingdom) are available at present in some European markets. Unlike the DPIs described earlier, these two reservoir-type inhalers meter the dose when the patient presses the top of the device similar to actuation of a pressurized metered-dose inhaler. Both devices contain a dose indicator, which is standard for reservoir multidose DPIs. Recently, Innovata presented the Twinhaler for asthma combination therapy, a new development based on the Clickhaler. This device does not require the combined drugs to be formulated in one powder blend but delivers two powder formulations from two reservoirs into one airflow path. 

Dmgs administered by inhalation are mostly intended to have a direct effect on the lungs. However, the efficiency of inhalation therapy is often not high because of the difficulty in targeting particles to the sites of maximal absorption. Only about 8% of the inhaled dose of sodium cromoglicate administered from a Spinhaler device (see section 9.9.2) reaches the alveoli. ... 

Advances in the equipment for the administration of aerosol medication to horses have facilitated the widespread use of inhalation therapy in equine medicine. Newer aerosolization devices ease administration and make pulmonary drug delivery efficient. Aerosol therapy is likely to become the mainstay of treatment for horses with heaves and may prove beneficial in the treatment of infectious respiratory disease in horses. 

BronchodUator classes available for the treatment of COPD inclnde /82-agonists, anticholinergics, and methylxanthines. There is no clear benefit to one agent or class over others, althongh inhaled therapy generally is preferred. In general, it can be more difficnlt for patients with COPD to nse inhalation devices effectively compared with other popnlations owing to advanced age and the presence of other comorbidities. Clinicians shonld advise, connsel, and observe patient techniqne with the devices frequently and consistently. 

A number of devices are available for the delivery of medications for inhalation therapy. Among these are the nebulizer, atomizer, and insufflator, which operate under Bernoulli s Principle. 

Recognizing the fact that pMDIs were the most widely used form of inhaled therapy and available in all markets for all types of inhaled respiratory medicine, it was felt that their use did justify an essential use exemption from the Montreal Protocol. Dry-powder devices were recognized as an alternative for many, but they were not available in all countries for all medicines and were not always suitable for the young and those with low inspiratory flow rates also, they may not be suitable in certain humid climates. In some markets their extra cost would also deprive many of necessary treatment. 

The recovered aerosolized insulin solution was similar to that of cells treated with a control insulin sample. Also the addition of additives used for the insulin aerosolization impair the plasma glucose-lowering action of subcutaneously injected insulin. For these reasons, the potential use of an inlqet device for insulin inhalation therapy for diabetes has been suggested (50). 

S. Onoue, et al. New treatments for chronic obstructive pulmonary disease and viable for-mulation/device options for inhalation therapy. Expert Opin DrugDeliv 6,793-811,2009. B.M. Ibrahim, et al. Challenges and advances in the development of inhalable drug formulations for cystic fibrosis lung disease. Expert Opin DrugDeliv 8, 451-466, 2011. 

Respirators are of two basic types air filtering and air supplying. Medically speaking, respirators also are used in hospitals and inhalation therapy work for treatment of disease. We have considered respirators for industrial usage only. Respirators restrict the atmosphere inlialed into the lungs by covering the nose and the mouth. Five different devices provide this covering ... 

Several devices are also available to promote airway clearance. Flutter valve devices employ oscillating positive expiratory pressure (OPEP) to cause vibratory air flow obstruction and an internal percussive effect to mobilize secretions. Intrapulmonary percussive ventilation (IPV) provides continuous oscillating pressures during inhalation and exhalation. Finally the most commonly used technique is high-frequency chest compression (HFCC) with an inflatable vest that provides external oscillation. Vest therapy is often preferred by patients because they can independently perform the therapy even from an early age.5,14... 

Dalby, R. N., Hickey, A. J., and Tiano, S. L. Medical devices for the delivery of therapeutic aerosols to the lungs, in Inhalation Aerosols Physical and Biological Basis for Therapy (Lung Biology in Health and Disease, Vol. 94). New York Marcel Dekker, 1996. 

Buck, H. (2001), The ideal inhaler for asthma therapy, Med. Device Technol., 12, 24-27. 

Virchow, J. C. (2005), What plays a role in the choice of inhaler device for asthma therapy Curr. Med. Res. Opin., 21(Suppl. 4), S19-S25. 

Q1 The most commonly used reliever in asthma therapy is a short-acting bronchodilator, such as the beta-2-agonists (/ -agonists) salbutamol or terbutaline. These are safe and effective agents for mild to moderate symptoms and are taken directly into the respiratory tract via an inhaler device. 

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