title: When should your asthmatic patients refill their MDI propelled with chlorofluorocarbons?
abstract: BACKGROUND
  The United States Food and Drug Administration has changed its policy regarding product labeling of asthma MDIs. All asthma MDIs propelled by CFCs should be discarded at the discard point labeled on the canister and box. This policy is in transition with inconsistent product information given to patients and physicians. Previously, patients had been educated to replace the canister by observing its floating pattern in water. Now FDA labeling asks users to count the number of actuations.
  
  
  OBJECTIVE
  To compare the discard point of sample and prescription-size Serevent (6.5 g and 13 g) and Vanceril 84 DS (5.4 g and 12.2 g) canisters to their floating pattern and total number of actuations in the canisters.
  
  
  METHODS
  Seven canisters each of Serevent 6.5 g and 13 g as well as Vanceril 84 DS 5.4 g and 12.2 g were shaken vigorously prior to actuation. One minute separated each actuation. The floating pattern was observed beginning at 80 percent of the discard point. This was repeated to the last actuation of the canister.
  
  
  RESULTS
  The floating pattern (tilt point) indicative to replace the Serevent 6.5 g and 13 g canisters as well as Vanceril 84 DS 5.4 g canister occurred after the discard point was reached.
  
  
  CONCLUSIONS
  Floating patterns of the 6.5 g and 13 g Serevent inhaler as well as the 5.4 g Vanceril 84 DS do not assist the asthmatic patient in determining when to replace their canister. Because canisters have excess product and propellant beyond the labeled discard point, it may be possible for pharmaceutical companies to correlate the product's floating pattern to the drug concentration and particle size distribution up to and beyond the discard point. Through careful testing, floating patterns of MDIs may still be able to assist the asthmatic patient in determining when to discard the canister.
authors.affiliation: Thomas Jefferson Medical College, Medical Center of Delaware, USA.
authors.forename: A G
authors.initials: AG
authors.lastname: Weinstein
mesh_terms: D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D017402:Chlorofluorocarbons; D004348:Drug Labeling; D004349:Drug Packaging; D006801:Humans; D009330:Nebulizers and Vaporizers / Q000592:standards*; D000068299:Salmeterol Xinafoate; D014481:United States; D014486:United States Food and Drug Administration
chemical_list: D001993:Bronchodilator Agents; D017402:Chlorofluorocarbons; D000068299:Salmeterol Xinafoate; D000420:Albuterol