WASHINGTON, D.C. - In an effort to reduce the amount of chlorofluorocarbons (CFCs) in the atmosphere, several drug companies have proposed, or are already marketing, powder-based inhalers for asthmatics.
The effort comes on the heels of the Montreal Protocol treaty signed by 140 countries over a decade ago pledging to accelerate elimination of CFC-based products from the market. The Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) have begun enforcing the treaty and many pharmaceutical firms have followed by developing ozone-friendly, powder-based inhalers. More than 70 types of asthma inhalers are currently sold, the majority of them CFC-based inhalers. Federal estimates indicate that inhalers are responsible for about 2% of total CFC emissions in this country.
Of the new powder-based inhalers on or close to being on the market, one has a built-in "space device," while two come in different flavors. The names of these new delivery systems are enough to confuse any asthmatic: Rotohaler, Turbohaler, the Discus, the Disk Haler, Smart Mist device, The Inhaler, The Prohaler, The Biohaler, the Ultrahaler--It could also become very confusing for the practicing doctor to keep straight.
"We've come a long way since the days of the BDP, when it was the only inhaled steroid available, only came in one strength, and had one taste," said Michael J. Welch, MD, associate clinical professor at the University of California at San Diego School of Medicine. "But as we move into the 21st century [the new medications] are going to be even more confusing, particularly with the number of new delivery devices and systems in the pipeline right now. [Doctors] will need to be clear as to how these new [products] differ in terms of efficacy, drug delivery, and safety aspects associated with their long term use."
Astra's Pulmicort Turbohaler was introduced last fall after being marketed for the last decade in Europe for use in asthma treatment. The benefit of dry powder asthma treatment, say supporters, is that it delivers asthma medication just as well as aerosols without threatening the environment. In addition to this, patients must coordinate their breathing with the aerosol propellant to be able to inhale the medication. This sometimes leads to wasted product if patients do not coordinate their breathing correctly. But new devices like the Turbohaler correct this problem because the medication is drawn in when the patient inhales. Each inhaler can deliver 200 doses per container and provides 200 mg of budenoside powder, said Astra researchers.
Dura Pharmaceuticals plans to launch its Albuterol Spiros Inhaler. Like the Pulmicort inhaler, the Spiros is designed to deliver a relatively consistent dose of drug to the lungs independent of the patient's ability to inhale forcefully. It uses no CFC propellants and requires minimal patient coordination. The cassette is usually replaced after 30 doses. Each inhale can deliver about 108 mg of albuterol sulfate to the system.
St. Paul, Minn.-based 3M Co.'s Proventil HFA has been on the market for over a year now and has taken most of the heat from critics who say that the powdered form of asthma inhalants are not as effective as those based on CFC propellants. But the FDA said there won't be any wholesale disappearance of the current inhalers on the market because the phasing-out process is lengthy.
"It takes a while to get a product on the market. It took [3M] eight years to get [Proventil on the market]," said Gene Harris, 3M's program manager for Proventil development.
Powder-based asthma products have been around for quite some time in Europe despite being relatively new to the 15 million Americans who suffer from asthma. For example, the spinhaler capsule, a drug delivery system in which the asthmatic punctures the powder-based capsule and simply inhales the drug, is already being used in this country. However, present powder inhaler technology has moved beyond the spinhaler capsule and is just as effective as its CFC-based counterpart, said Kathi Schumacher, chief of the products management staff at the FDA.
"It's ever-changing technology, so newer products coming into the pipeline will be much more sophisticated and have better delivery systems than those now being introduced," Schumacher said. "So far we have seen no difference in the two asthma delivery systems, but we will make sure Americans with asthma continue to get effective treatment."
Some companies say the new inhalers will be "child-friendly" and easy to manipulate. The powder may be a little easier to swallow because, unlike CFC cartridges which give the asthmatic a quick blast sensation then a lingering metallic taste, powder-based inhalers will have a time-release that gives off a sweet taste due to the carrier molecules in the powder, said industry officials. The planned dosages will be the same for children and adults. There have been no reported instances of severe child reactions to the powder medications.
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