4 mg versus 48.5 mg of iron over
a 4-hour period, respectively, indicating that Folifer® is likely to have increased bioavailability compared with Ferroliver®. This result is even more surprising considering that Ferroliver® has a slightly higher elemental iron content. In this respect, the role of the different iron salts in each drug — ferrous sulfate (in Folifer®) and ferrous fumarate (in Ferroliver®) — should be noted. Ferrous sulfate has an improved dissolution profile compared with ferrous fumarate because of its superior degree of solubility in acid. This difference is likely to be the main reason for the observed results and the lack of equivalence between the two products. However, since the two products differ R788 research buy slightly in their chemical composition, we cannot exclude the possibility PD0325901 of bias in the study. While we recognize that this is a potential limitation of this study, there is no known scientific rationale for folic acid, vitamin B12, or copper sulfate significantly influencing the in vitro dissolution of iron. The selectivity of cerimetric titration for the quantitation of iron (II) in the presence of inert excipients was demonstrated in the validation results. Excipients and other active ingredients found in the formulas were not expected to have any relevant influence on the assay, as they either did not have any relevant oxidation-reduction
behavior, or they were present at very low levels relative to the amount of iron. Finally, the information that arises from application of the formula for calculating the similarity factor (equation 1) shows both drugs have different in vitro dissolution profiles and so are unlikely to be bioequivalent. This study reinforces the importance and differentiation of ferrous sulfate and ferrous fumarate as iron salts. Previous evidence suggests that different iron salts show
similar tolerability in clinical use. In two studies comparing the absorption of ferrous sulfate and ferrous fumarate from fortified milk-based drinks, one study found that ferrous sulfate was better absorbed than ferrous fumarate, while absorption of ferrous sulfate and ferrous Atazanavir fumarate did not differ significantly in the second study. Given the significant effects that the type of salt may have on in vitro dissolution, ferrous sulfate-containing supplements such as Folifer® may therefore be a better choice for iron/folic acid supplementation in individuals at risk of iron/folate deficiencies, such as pregnant and lactating women. Conclusion Despite containing similar amounts of elemental iron, Folifer® showed greater dissolution of iron compared with Ferroliver®. This study highlights the importance of some iron salts (such as ferrous sulfate) on the bioavailability of iron supplements.