CFC transition: the Emperor's new clothes. Each class of drug deserves a delivery system that meets its own requirements

It is likely that two related but very different events during this coming year will form milestones in the history of aerosol therapy. One is likely to represent a genuine advance, ushering a new era in which aerosol delivery systems will be used to deliver potent systemically acting drugs via the lungs. The other will be the culmination of an enormously expensive exercise aimed at perpetuating inappropriate technology.

It seems probable that, during the later part of 2000, the FDA will grant a licence to deliver insulin as an aerosol. The most exciting aspect of this is that, for the first time in half a century, an aerosol delivery system has been developed specifically to fulfil a specific task.1 The biggest market in North America for inhaled insulin is likely to be in the treatment of type II diabetes and, although the potential for significant adverse events related to swings in blood sugar is probably less than in those with traditional insulin dependent diabetes, it is still necessary to deliver the insulin in reproducible quantities to the lungs. If successful, this product is likely to be the first of a new generation of products designed to deliver systemically acting drugs via the respiratory tract. This concept is not new; early pioneers working with jet nebulisers in the 1930s and pressurised metered dose inhalers (pMDIs) in the 1950s considered delivering insulin as an aerosol but soon abandoned the idea because they realised that delivery of drug to the lung was so unpredictable that it was not possible to utilise aerosolised insulin safely with those devices.

In contrast, this year is also likely to see the widespread introduction of chlorofluorocarbon (CFC) free pMDIs delivering inhaled steroids.2 This “seamless” transition in which hydrofluorocarbon (HFC) replacement devices have been detuned to perform …