Inhaled therapies delivery device

A native American woman developed a rise in methemoglobin from 0.9 to 9.4% over 6 hours of inhaled nitric oxide therapy, 80 ppm with reduction of the dose to 40 ppm, methemoglobin returned to basehne concentration. A patient who received inhaled nitric oxide through an imprecise delivery device had a methemoglobin concentration of 67%. Another patient who received a dose of 110 ppm had a methemoglobin concentration of 19%. 

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. 

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. 

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. 

Some progress has been made in developing alternative devices for the delivery of inhaled antimicrobial therapies. Colistin has been formulated in a dry powder inhaler and evaluated in healthy individuals and patients with cystic fibrosis [40]. Peak semm concentrations of colistin were 2.5-5 times higher when 25 mg of colistin sulfate dry powder was inhaled compared to 160 mg of colistin sulfomethate delivered by nebulization. Some patients experienced a decrease in pulmonary function and severe cough with the dry powder however, the investigators felt that this may be improved with a reduction in dose. 

The uncontrolled inhalational use of technical-grade NO is occurring for a variety of indications. Further complicating this situation is the scarcity of properly manufactured and inspected delivery and monitoring devices for inhaled NO therapy. Many clinicians use home assemblies of such equipment. 

The most important development in antiasthma drug delivery was the advent of the metered-dose inhaler in 1956, which resulted in a huge increase in the use of antiasthma therapy. Sales of pressurized metered-dose inhalers now run at approximately 500 million per year. However, the introduction of this device was not without problems. This section of the chapter covers the early use of propellants in atomization, the origin of the metered-dose inhaler, and the epidemic of asthma deaths. 

The pulmonary and transdermal routes are the least investigated of the alternative, nonparenteral delivery routes for insulin, and perhaps therefore they still hold some promise. The potential of pulmonary delivery for bolus therapy has been demonstrated as this route is feasible from a bioavailability standpoint, even without the addition of enhancers. However, long-term safety remains to be established. Inhalation of insulin may offer fairly reproducible absorption kinetics, but it is a major challenge from a device point of view to ensure reproducibility of the administered dose. 

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