Ivax ( IVX) Wednesday said it had received an approvable letter from the federal regulators for its asthma treatment. The Miami-based biotech firm said the Food and Drug Administration had sent the letter regarding the company's new drug application for albuterol sulfate using a CFC-free propellant in its patented breath-activated aerosol inhaler. Ivax's breath-activated aerosol inhaler is already in use in Europe. The device eliminates the need to coordinate the manual release of the medicine with its inhalation, which is required by standard metered dose inhalers. The company previously received an approvable letter from the FDA on a separate NDA for an HFA formulation of albuterol in a standard metered dose inhaler. Ivax shares fell 14 cents, or 0.6%, to $24.18. Typically, companies resubmit an NDA after receipt of an approvable letter with the intention of answering all of the questions that need to be addressed prior to approval.