The evolution of lung drug-delivery technology has undergone significant advances over the last few decades, so that today it is one of the most effective and rapid modalities for treating pulmonary diseases. Many of these diseases are localized in the lung, examples being asthma, allergic airway disease (AAD), chronic obstructive pulmonary disease, and adult respiratory distress syndrome (ARDS) or emphysema. Of the series of drugs used in these conditions, the most common therapeutic entities include -agonists, steroids, mucolytics, and cholinergics. However, a large number of compounds have recently been aimed at for systemic delivery via the airways, especially those that are challenging or infeasible for oral delivery, such as peptides and proteins. If systemic concentrations achieved by lung delivery could exceed minimum effective therapeutic requirements, the lung might become an effective route for drugs intended for treating certain systemic diseases. Insulin, leuprolide, and a variety of other therapeutic peptides and proteins that are in various phases of clinical development might be effective drug therapies tomorrow. In fact, Exubera, inhaled insulin using a proprietary inhalation device and powdered insulin formulation developed by Nektar Therapeutics, was recently approved for marketing by the
AKWETE L. ADJEI Kos Pharmaceuticals, Cranbury, New Jersey, U.S.A.