Flunisolide HFA for the treatment of asthma: an old friend reformulated

The environmental mandate to eliminate the production of ozone-depleting products including chlorofluorocarbon (CFC) propellants has encouraged much needed research into improving modes of delivery of inhaled corticosteroids and enhancing drug deposition. Consequently, flunisolide CFC, an inhaled corticosteroid with a proven track record in the treatment of asthma, has been reformulated using a hydrofluoroalkane (HFA) as a propellant and is now awaiting FDA approval. Flunisolide HFA is a solution aerosol, unlike flunisolide CFC which is a suspension aerosol. As a solution aerosol, flunisolide HFA has a smaller mean particle size than flunisolide CFC. In addition, the built-in spacer included in the flunisolide HFA inhaler acts to reduce ex-actuator particle size; the smaller particle size of flunisolide HFA results in an improved deposition profile. Flunisolide HFA has substantially more lung deposition and much less oropharyngeal deposition than flunisolide CFC. Limited information is currently available on the clinical performance of flunisolide HFA. A single dose-response study has been performed in adults and in children comparing multiple doses of flunisolide HFA and flunisolide CFC. These studies indicate that flunisolide HFA is effective in controlling asthma. No unusual safety concerns have been noted, although further studies are needed to determine the long-term systemic effects of flunisolide HFA.