Zein Beta-Cyclodextrin Micropowders for Iron Bisglycinate Delivery

Given the limited number of materials available to design delivery platforms for nutrients,
the rational combination of raw materials already approved as food ingredients and their processing
through nano-micro technology can offer a unique tool for innovation. Here,we propose a nano-in-micro
strategy to produce powders based on the hydrophobic protein zein, useful for the oral delivery of
a hydrophilic iron source (iron bisglycinate) in anaemic patients. Iron-loaded powders were prepared
through a two-step strategy consisting in the formation of a zein pseudolatex followed by a spray-drying
step. To extend the manipulation space for zein and entrap iron bisglycinate, -cyclodextrin (CD) was
selected as helping excipient. Addition of CD allowed iron loading in the pseudolatex and greatly
increased product yields after the drying process as compared to zein alone. Iron-loaded micro-sized
powders were characterised by attenuated total reflectance-Fourier transform infrared (ATR-FTIR)
spectra, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to elucidate the
role of CD as a compatibilizer for the zein-iron system. Remarkably, micropowders released only
20% of FeBIS in a simulated gastric fluid, whereas release in a simulated intestinal fluid was almost
completed in 7 h. In summary, CD association to zein is a novel strategy to expand applications in the
oral delivery of iron bisglycinate and, prospectively, to micronutrient chelates.