Comparison study of oral iron preparations using a human intestinal model

Area of Science:

• Nutritional Science
• Gastroenterology
• Pharmacology

Background:

• Iron deficiency and iron deficiency anaemia (IDA) are the most common nutritional deficiencies globally.
• Standard IDA treatment relies on oral iron supplements, typically ferrous salts (e.g., ferrous sulfate, fumarate, gluconate).

Purpose of the Study:

• To compare iron uptake and absorption from various oral iron supplement preparations available in the UK.
• To investigate the impact of formulation ingredients and physical characteristics on iron absorption.
• To evaluate iron absorption under physiologically relevant conditions using a novel dissolution-absorption protocol.

Main Methods:

• Utilized the Caco-2 human epithelial cell line to assess cellular iron uptake, measured by intracellular ferritin formation.
• Developed a two-stage dissolution-absorption protocol simulating physiological conditions.
• Compared dissolution rates and iron absorption across conventional-release and modified-release ferrous iron formulations.

Main Results:

• Significant variations in dissolution times were observed: conventional tablets dissolved in 48–64 minutes, while modified-release forms took 256–274 minutes.
• Conventional-release ferrous sulfate tablets exhibited the highest iron absorption.
• Modified-release ferrous preparations consistently showed significantly lower iron absorption compared to controls (P < 0.05).

Conclusions:

• Oral iron preparations display considerable variability in dissolution rates and iron uptake.
• The physical characteristics of iron supplements, including release mechanisms, critically influence iron absorption.
• Formulation plays a key role in the efficacy of oral iron therapy for iron deficiency.