Browsing by Author "Silva, Joana Cruz Henriques"
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- Inhalable mannitol microparticles as antigen carriersPublication . Silva, Joana Cruz Henriques; Grenha, AnaEven with scientific advances, lower respiratory tract infections pose a serious danger to human life worldwide. Lower respiratory tract infections remained the deadliest infectious disease in 2019 and were the fourth most prevalent cause of death globally, according to the World Health Organization. Different bacteria and viruses, such as S. pneumoniae or SARS-CoV-2, can cause respiratory infections. Thus, prevention is crucial in the management of lower respiratory tract infections. Immunisation strategies regarding the prevention of lower respiratory infections include parenteral immunisation or even oral antigen delivery. In any case, it seems that lung protection is insufficient because lung infection often develops. A pulmonary immunisation technique seems promising because the lung is the primary site of infection. The use of the pulmonary route ensures that a local immune response is produced along with systemic immunisation, while avoiding adverse effects, such as liver metabolism, or protein degradation associated with the oral route. Appropriate drug delivery systems, such as microparticles, might be the adequate means to comply with the aerodynamic requisites needed for successful lung delivery. Spray-dried microparticles comprising mannitol and a commercial formulation of bacterial lysates, produced by spray drying, are proposed for lung immunisation. Varying the mannitol/bacterial lysates mass ratio, several formulations of bacterial lysates-loaded microparticles were successfully produced. The association efficacy of the bacterial lysates was confirmed, reaching values of 50% and 65%. Aerodynamic evaluation was performed by cascade impaction using a methodology of gravimetry or the direct drug determination by Bradford method. The microparticles showed mass mean aerodynamic diameters between 5.9 and 7.3 μm, with the potential to reach the lung, mainly its upper part.