| Iron amino acid chelates is promising iron fortifier used to combat iron-deficiency malnutrition, which is more stable and more bioavailable than the common iron fortifier such as ferrous sulfate. However, iron amino acid chelates are not stable under strong acid condition, and the complexes can be dissociated to inorganic iron salt, so the effect of combating iron-deficiency is decreased. As a nano-delivery system (NDS), nanoliposomes are a possible route that is helpful to improve and increase the stability of iron amino acid chelates, and to enhance oral bioavailability of the complexes.Ferrous glycinate was selected as a representative of iron amino acid chelates. The preparation, characterization, antioxidant activity and iron availability of ferrous glycinate was systematically investigated; existence states of ferrous glyciante prepared from different methods was evaluated; preparation and stability of ferrous glycinate nanoliposomes was studied; effect of ferrous glycinate nanoliposomes as iron source on physical-chemistry property of milk-fortified was estimated; the feasibility of using nanoliposomes as an oral delivery system to improve the bioavailability of ferrous glycinate was examined using iron-deficiency anemia SD rats as the model.Ferrous glycinate was prepared using glycine and ferrous chloride in aqueous system, and the product was separated from the reactive system using organic solvent-deposition method. The product was stored at low temperature 4℃or-18℃for 24 h, and then the product was dried in a vacuum drying oven to get soluble ferrous glycinate or in a freeze drier to get sparingly soluble ferrous glycinate. The results of element analysis showed that soluble and sparingly soluble ferrous glycinate have the same element composition, and the molar ratio of Fe(II):N:H2O was 1:3:1. Molar conductivities of soluble and sparingly soluble ferrous glycinate were 22.00 and 27.80Ω-1cm2mol-1, respectively. Fourier transform infrared (FT-IR) spectra, X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) of soluble and sparingly soluble ferrous glycinate were significantly different from that of free glycine ligand. Coordination bonds were formed between Fe(II) and glycine, and iron-glycine chelate was produced. The results of zeta potentials showed that soluble ferrous glycinate solution was molecular solution, and the absolute value of zeta potential was small; sparingly soluble ferrous glycinate solution was pseudosolution, and the absolute value of zeta potential was bigger.Ferrous glycinate nanoliposomes were prepared using reverse phase evaporation method. Effects of CHOL, Tween 80, ferrous glycinate concentration, pH of hydrating media, and sonication strength on EE were investigated. The optimized technology parameters were CHOL/EPC 1:8, Tween 80/EPC 1:2, ferrous glycinate/EPC 3:10, hydrating media pH 6.8, and sonication power 300 W, and the EE was 84.80% under the condition. The results of VZM photo showed that ferrous glycinate liposomes were spheral shape, and size distribution was homogeneous. Mean diameter was 559.2 nm; polydispersity index (PDI) was 0.313; zeta potential was+9.6 mV. The release of ferrous glycinate liposomes in vitro showed that little core material was released from liposomes in the first 4 h in simulated gastrointestinal juice. The mean diameter of liposomes increased from 559.2 nm to 692.9 nm and 677.8 nm after incubation in simulated gastrointestinal juice of pH 1.3 and pH 7.5, respectively. VZM photo of ferrous glycinate liposomes showed that the liposomes were still spheral shape after incubation. The stability of ferrous glycinate in strong acid environment was greatly improved by encapsulation in liposomes.Ferrous glycinate nanoliposomes with the EE of 76.2% were prepared by reverse phase evaporation method coupling sonication. The TEM micrographs showed that ferrous glycinate nanoliposomes were spherical-shaped vesicles, and most of they were less than 100 nm in diameter; the mean diameter and PDI index were 101.3 nm and 0.361, respectively. During 3 month storage period, some core material was leaked out from nanoliposome, but the stability of nanoliposomal vesicles was not significantly damaged. After sonication, some core material was leaked out from nanoliposomes, and the mean diameter was obviously reduced from 101.3 to 86.8 nm, and PDI value was reduced from 0.361 to 0.261. During heating period, nanoliposomes was stable in the first 10 min, and then ferrous glycinate was significantly released from nanoliposomes; the mean diameter was changed from 101.3 nm to 103.5 nm, and PDI value was changed from 0.361 to 0.335. The results of effect of metal ions showed that univalent metal ions (Na+and K+) caused obvious leakage of nanoliposomes, and the mean diameter was not significantly changed; Mg2+ obviously caused leakage of nanoliposomes and increase of mean diameter; Ca+ didn't cause leakage of nanoliposomes, and the mean diameter was significantly increased. Furthermore, the results of in vitro release of small ferrous glycinate glycinate liposomes showed that about 15% ferrous glycinate was released from liposomes in simulated gastric juice at 37℃for 5 h; about 20% ferrous glyciante was release from liposomes in simulated intestinal juice at 37℃for 5 h; ferrous glycinate nanoliposomes could effectively protect ferrous glycinate.Compared with ferrous sulfate and ferrous glycinate, ferrous glycinate nanoliposomes (FGL) were more stable to fortify milk as iron source. Fat oxidation of FGL-fortified milk was weaker; sensory quality was better; organization structure was more stable.The effectiveness of treatment of iron-deficiency anemia with ferrous glycinate nanoliposomes was investigated using SD rats, and compared with that of ferrous glycinate and ferrous sulfate. Hb, serum Fe, total iron binding capacity, iron contents of liver and spleen were measured at the end of the intervention. Significant treatment effects were observed for Hb, serum Fe, total iron binding capacity, and iron contents of liver and spleen (P<0.05) in ferrous glycinate nanoliposomes group. Ferrous glycinate nanoliposomes as an iron supplement performed better that ferrous glycinate and ferrous sulfate in groups of iron-deficient rats. Ferrous glycinate nanoliposomes may be the choice of iron for the treatment of iron-deficiency anemia because of its high effectiveness. |
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