Stability of freeze-dried ovalbumin-alginate microspheres with different lyoprotectants

Stability and denaturation has been widely known as main disadvantages in the oral delivery of drug or protein. The aim of this research was to investigate stability of ovalbumin-alginate microspheres during production and storage. Ovalbumin-alginate microspheres were prepared using sodium alginate polymer, CaCl₂ cross linker and different lyoprotectants (malt odextrin and lactose) produced using aerosolization technique. Freeze-dried microspheres were stored at temperature 4 ± 2°C; 25 ± 2°C and 50 ± 2°C for a period of 60 days were observed at day 0, 7, 30 and 60. Changes of organoleptic, morphology, entrapment efficiency, protein loading, and moisture content were observed. Structural integrity by SDS-PAGE method was also studied. Results showed that no significant changes in morphology after storage at 50°C for 60 day confirmed by Scanning Electron Microscope. Profile of SDS-PAGE showed that no significant differences were observed of the molecular weight after 60 days of ovalbumin-loaded microspheres using both maltodextrin and lactose lyoprotectants when compared to protein marker and ovalbumin standard. Based on factorial design statistic analysis, no interaction between type of lyoprotectant and temperature that affected entrapment efficiency and protein loading was found. Stability studies during 60 days indicated the potential of ovalbumin-loaded alginate microspheres for oral delivery systems.