Dry powder inhalation as a potential delivery method for vaccines

Measles vaccine is administered to millions of children annually via a perc utaneous injection. There are, however, compelling reasons to search for al ternative routes of administration, especially in mass vaccination campaign s. Two key factors are (1) decreased stability of the vaccine upon reconsti tution and, (2) the potential risks of contamination associated with needle s. Dura has developed a unique inhaler that can deliver a powder dose via t he pulmonary route for local or systemic action. The breath-actuated Spiros (R) inhaler uses electromechanical energy to aerosolize and deliver a consi stent dose over a wide range of inspiratory flow rates. To achieve alveolar (deep lung) deposition for subsequent systemic absorption, dry-powder vacc ine is size reduced to a mass median diameter between 1 and 5 mu m. Small v accine particles are blended with an inert carrier to improve dispersion. M easles vaccine formulated as a powder blend may be more thermostable than e xisting reconstituted formulations. The Spiros(R) technology is available i n three powder storage platforms. Two of these formats are designed specifi cally for moisture and/or light sensitive compounds and may be particularly suitable for delivery of measles vaccines in mass campaigns because their design (1) eliminates the need for powder reconstitution, and (2) reduces t he risk of contamination. (C) 1999 Elsevier Science Ltd. All rights reserve d.