Effect of drying techniques on microstructure and functional properties of tragacanth-insulin microparticles

Numerous antimicrobials, hormones and enzymes as bioactive peptides/proteins could take advantage of oral delivery. Microparticles produced by complexation of two polyelectrolytes may have prospective use as a carrier for oral administration of proteins/peptides. Food polysaccharides like alginate, carrageenan, pectin, tragacanth and dextran can be potential excipients for this purpose. In this research, microparticles were created by the inclusion of bioactive protein/peptides into a tragacanth hydrogel accompanied by drying process. Insulin was utilized as a bioactive proteins model. Bioactive protein and tragacanth microparticles created at various pH and drying methods (freeze drying and spray drying) were assessed by SEM analysis and ATR Fourier transform infrared (ATR FTIR). The SEM study revealed that sub spherical microparticle was produced using spray drying process while the porous structure was produced using the freeze-drying method. In FTIR study, the complexes between tragacanth and insulin displayed amide absorption bands appearing in the protein spectra and exhibited the formation of new chemical substances. This finding indicates that both spray and freeze dried microparticles may act as a potentially promising device for oral delivery of bioactive proteins and peptides.