The effect of protein stabilizers on the physical state and aerosol performance of spray-dried albumin microparticles

The effect of protein stabilizers on the physical state and aerodynamic behavior of spray-dried bovine serum albumin (BSA) was investigated. Two per cent (w/v) solid content BSA solution was spray-dried alone (F1) or with Tween 80, 1:10 molar ratio (F2) or zinc ion, 1:50 molar ratio (F3). The results showed that Tween 80 and zinc ion both could successfully inhibit aggregation of protein during spray-drying process. The volume median diameter (d50%) of F1, F2 and F3 powders was 4.6, 3.5 and 4.9 μm, respectively. SEM micrographs revealed different particle shape and surface texture for spray-dried powders. In this study coarse lactose was used as carrier and the in vitro deposition behaviors of the carrier free and carrier blended formulations were examined separately by an Andersen Cascade Impactor (ACI). Spray-drying of F1 showed the microparticles with the highest fine particle fraction (FPF) of 48.20% and dispersibility of 69.89%. In vitro deposition test of the carrier blended formulations showed controversial results, since coarse lactose improved the aerodynamic behavior of F2 from 8.45 up to 36.18%, but other samples showed diminished deposition data. In conclusion, the selected stabilizers, protected the BSA efficiently during the spray-drying process, but their effect on the aerosol performance of the produced powders was quite different, depending on the physical properties of the powders.