The promise of inhaled delivery lies in its application to therapeutic proteins, which often cannot be delivered orally. But many dry powder and aqueous solution formulations have encountered problems such as reproducibility and stability. Scientists last week described using ethanol, a nonaqueous solvent, to deliver an insulin suspension to rats, demonstrating that the technique produces a stable protein formulation with bioavailability comparable to that of other inhaled products.

Writing in the Proceedings of the National Academy of Sciences, scientists from MIT and Harvard University