Asthma inhalers are designed to disperse asthma medications to the target areas in the lungs. These areas include the mucosa and smooth muscles of the bronchioles. Inhaler devices should be able to deliver medications with minimal drug loss to the surrounding tissues; this ability ensures that the required dosage reaches the target cells.
A Summary of Inhaler Types
Medication delivery methods and systems are designed to suit the individual patient’s disease condition and personal preference.
Types of Inhalers:
- Metered Dose Inhalers (MDIs): The inhaler produces an aerosol of the medication which is then inhaled by the patient. These are the most commonly used devices. They are inexpensive and efficient. Pressured MDIs use a chemical propellant that helps disperse the medication. The inhaler is activated by either squeezing the inhaler or by inhalation activation. The drug is initially mixed with a chemical propellant and kept under pressure. When the device is activated the drug is released along with the propellant as a fine mist. MDI inhalers used to use chlorofluorocarbons (CFCs) as the chemical propellant but CFCs are being phased out of all uses, including inhalers. This is because CFCs have been identified as ozone depleting compounds. The CFCs are being replaced in inhalers by hydrofluoroalkanes (HFA).
- MDIs with a Spacer: The spacers help deliver the drug optimally by holding the required dose. This allows the user to inhale the medication at a slower rate. This makes its passage to the lungs more effective.
- Dry Powder Inhalers (DPIs): Chemical propellants are not used in these systems. The medication is dispersed by the patient’s ability to take a deep and fast breath. DPIs are breath activated. The patient breathes in the required dosage of medication.
Trends in Asthma Inhalers
For the most part inhalers have not changed much. The advances in inhaler development are geared towards making them more efficient and viable.
- Using GPS devices on the inhalers have allowed researchers to pin point danger spots for asthma sufferers. The researchers attached GPS devices to rescue inhalers and were able to determine where a patient was before they used their device to relieve activated symptoms. The device will also be able to help pin point sites that exacerbate asthma sufferers and worsen their symptoms.
- Implementing electronic monitoring of medication dispersed. These inhalers will be equipped with a microelectronic monitor that will record the doses dispersed. This will help keep users on track with their asthma management plans. Some of these new devices will be able to alert the patient if a dose is missed. These new systems will be important in ensuring that the patients follow the prescribed therapy in a real life setting. The device will also have the ability to alert the patients if the canister is almost empty.
- Improving medication delivery. Researchers are placing emphasis on the efficiency of the mouth piece of the inhaler. Designs are being developed that minimize throat deposition. This ensures that the medication enters the targeted areas of the lungs. This will make the inhalers more efficient.
Future of Inhalers
Inhalers will be designed to monitor the ambient air and determine whether medication should be administered to deter attacks. They will also have the capability of precisely delivering the medication to the lungs without using propellants that may or may not be harmful to the atmosphere or to the asthmatic patient. Asthma inhalers may even be developed to be pro-active, notifying a patient’s physician if there is a change in the asthma management plan.
Sources
Morris, Michael. "Asthma: EMedicine Pulmonology." EMedicine - Medical Reference. 19 Feb. 2010. Web. 20 Apr. 2010. .
Straka R, Fish J, Benson S, Suh J. “Patient self-reporting of compliance does not correspond with electronic monitoring: an evaluation using isosorbide dinitrate as a model drug.” Pharmacotherapy. 1997;17:126–132
Simmons et al. “Validation of the Doser; a new device for monitoring meter-dose inhaler use. “ J Allergy Clin Immunol 1998;102:409–413
