A novel approach to oral iron delivery using ferrous sulphate loaded solid lipid nanoparticles

Abstract

Iron (Fe) loaded solid lipid nanoparticles (SLN’s) were formulated using stearic acid and iron absorp-tion was evaluated in vitro using the cell line Caco-2 with intracellular ferritin formation as a marker ofiron absorption. Iron loading was optimised at 1% Fe (w/w) lipid since an inverse relation was observedbetween initial iron concentration and SLN iron incorporation efficiency. Chitosan (Chi) was included toprepare chitosan coated SLN’s. Particle size analysis revealed a sub-micron size range (300.3 ± 31.75 nmto 495.1 ± 80.42 nm), with chitosan containing particles having the largest dimensions. As expected,chitosan (0.1%, 0.2% and 0.4% w/v) conferred a net positive charge on the particle surface in a concen-tration dependent manner. For iron absorption experiments equal doses of Fe (20 �M) from selectedformulations (SLN-FeA and SLN-Fe-ChiB) were added to Caco-2 cells and intracellular ferritin proteinconcentrations determined. Caco-2 iron absorption from SLN-FeA (583.98 ± 40.83 ng/mg cell protein)and chitosan containing SLN-Fe-ChiB (642.77 ± 29.37 ng/mg cell protein) were 13.42% and 24.9% greaterthan that from ferrous sulphate (FeSO4) reference (514.66 ± 20.43 ng/mg cell protein) (p ≤ 0.05). Wedemonstrate for the first time preparation, characterisation and superior iron absorption in vitro fromSLN’s, suggesting the potential of these formulations as a novel system for oral iron delivery