Production of bromelain aerosols using spray-freeze-drying technique for pulmonary supplementation

Spray-freeze-drying (SFD) is a promising technique to produce inhalable dry powder formulations that able to retain the integrity of bioactive compounds. Therefore, in this study bromelain aerosols were developed using SFD by varying core-to-wall ratios (1:10, 1:25 and 1:50). The maltodextrin was used to protect the bromelain during freezing and drying stages had a significant effect on the developed aerosols; as the concentration increased, the emitted dosage level increased to around 97.2%. The particles were found to be spherical and highly porous, with geometric diameter ranging between 4.71 to 7.46 mu m. All formulations were low in density, had excellent flowability and the theoretical mass median aerodynamic diameter (MMAD(t)) ranged between 2.97 to 3.33 mu m. The total bromelain concentration ranged between 413.73 to 462 mg/g and the activity was found to be between 333.22 to 404.64 casein digestion units(-1) (CDU)(-1) for all three formulations. The XRD patterns explained the crystalline nature of these formulations. The in-vitro release profile showed that the release of bromelain was slow and sustained for 12 h and 46 to 55% of release was estimated. In-vitro aerosol performance of particles showed 84.28% fine particle fraction (FPF) and MMAD of 3.2 mu m for the 1:25 formulation. Thus, this study confirmed that SFD can produce aerosols with desired properties and the approach can be used for pulmonary supplementation of food bioactives with good retention and activity.