Absorption of controlled-release iron

Abstract

A multiple-dose double radioiron technique was used to compare absorption of Fe administered as a controlled-release (CR) capsule and as an elixir; both formulations contained 50 mg elemental Fe as ferrous sulfate. When taken by normal subjects in the fasting state, mean absorption from the elixir and CR capsule averaged 4.92 and 4.38%, which gave a CR capsule:elixir ratio of 0.89. This difference was not significant, but when taken with meals that inhibit absorption of dietary Fe by different degrees, absorption of the CR formulation was superior. CR capsule:elixir absorption ratios averaged 1.70 from a meal that is mildly inhibitory and 3.13 from a meal that causes more marked inhibition. CR Fe formations may offer a therapeutic advantage to patients who take oral Fe with meals to avoid gastrointestinal side effects.