Landmark Inhaled TB Vaccine Developed

A new dry powder inhaled tuberculosis (TB) vaccine is easier to administer and store, and has been found to be just as effective as the injected vaccine used worldwide.

Researchers at the University of North Carolina (Chapel Hill, USA) designed an aerosol form of the Bacillus Calmette-Guérin (BCG) vaccine that exhibited an improved efficacy of immunization. The vaccine was produced by spraying a liquid through heated nitrogen gas to create a powder, in a process called spray drying. The microstructural properties of the vaccine were adapted to alter the dispersive and aerosol properties of the vaccine independently. The combination of nano- and micrometer-scale particulate dimensions possessed a greater ability to aerosolize than particles of standard spherical isotropic shape and of similar geometric diameter. The researchers concluded that the nanomicroparticle aerosol BCG vaccine exhibited high-efficiency delivery and peripheral lung targeting capacity from a low-cost and technically simple delivery system, and then tested it in a biologic model.

Aerosol delivery of the BCG nanomicroparticle to normal guinea pigs subsequently challenged with virulent Mycobacterium tuberculosis significantly reduced bacterial burden and lung pathology both relative to untreated animals and to control animals immunized with the standard parenteral BCG. The results of the study were published in the March 14, 2008, online edition of the Proceedings of the National Academy of Sciences (PNAS).

"It is at least as good as the injectable vaccine,” said lead author Anthony Hickey, Ph.D., of the molecular pharmaceutics division at UNC. "The real advantage is that this vaccine does not need to be refrigerated. It also doesn't require needles, syringes, and water like the injectable vaccine, and administering it is as easy as breathing in, making it ideal for use in developing countries.”

The dried nanomicroparticle vaccines possess two axes of nanoscale dimensions and a third axis of micrometer dimension; the last one permits effective micrometer-like physical dispersion, and the former provides alignment of the principal nanodimension particle axes with the direction of airflow


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