Plug C M, Dekker D, Bult A
Pharm Weekbl Sci. 1984 Dec 14;6(6):245-8. doi: 10.1007/BF01954553.
The greater absorption of iron in vivo from ferrous ascorbate [Fe(HL)2] as compared with ferrous sulfate has been ascribed both to retardation or prevention of Fe(II) oxidation by ascorbate and to the existence of Fe(II) as a chelate with ascorbate. The available literature and our own results demonstrate that Fe(HL)2 dissociates in aqueous solution into a monomeric cationic species Fe(HL)1+, Fe2+ and HL-. The HL anion acts as a monodentate. The low stability constant KFe(HL)1, about 20 l.mol-1 at mu = 0 and 25 degrees C, results in the conclusion that Fe(HL)2 is almost completely dissociated into Fe2+ and HL- at about pH = 5, so (chelate) complex formation does not contribute significantly to the increased iron absorption. Between pH = 6 and pH = 8 a solubility enhancing effect of ascorbate is observed which may be of relevance for the iron absorption from ferrous ascorbate.
与硫酸亚铁相比，体内抗坏血酸亚铁[Fe(HL)2]对铁的吸收更高，这既归因于抗坏血酸对Fe(II)氧化的延缓或预防作用，也归因于Fe(II)以与抗坏血酸形成的螯合物形式存在。现有文献和我们自己的结果表明，Fe(HL)2在水溶液中解离成单体阳离子物种Fe(HL)1+、Fe2+和HL-。HL阴离子起单齿配体的作用。在μ = 0和25℃时，低稳定性常数KFe(HL)1约为20 l·mol-1，由此得出结论：在pH约为5时，Fe(HL)2几乎完全解离成Fe2+和HL-，因此（螯合）络合物的形成对铁吸收增加的贡献不大。在pH = 6至pH = 8之间，观察到抗坏血酸的溶解度增强效应，这可能与从抗坏血酸亚铁中吸收铁有关。
