Numerous iron-containing preparations are available on the market; these vary in dosage, salt, chemical state of iron (ferric or ferrous) and in the iron delivery process (immediate or prolonged-release). Tardyferon® is a prolonged-release tablet containing 80 mg ferrous sulphate. The formulation has recently been modified; changes to the excipients which constitute the inert formulation matrix have allowed a decrease in tablet size for easier swallowing. The aim of this multicenter open-label study was to characterize the serum pharmacokinetics of iron in non-pregnant women aged 23-45 years with iron deficiency anaemia (IDA) following single oral administration of 160 mg Tardyferon® under fasting conditions. Blood samples were collected from the 29 participants before dosing and until 24 h post-dosing. Serum iron concentrations were determined using a routine colorimetric analytical method; pharmacokinetic parameters were derived using a non-compartmental approach. In these patients, median time to maximum serum concentrations (Tmax) was 4 h. Serum profiles were consistent with prolonged release; iron levels were elevated up to 12 h after dosing, with mean C 12h still more than 7 times higher than baseline (C T0 ), and mean C 2h and C 8h representing 69.7% and 81.9% of the C max , respectively. In vitro dissolution testing performed on the clinical batch also demonstrated prolonged release of iron from this formulation. A single oral dose of 160 mg Tardyferon® administered under fasting conditions to this target population resulted in a long-lasting release of iron in the gastrointestinal tract, leading to optimal iron absorption. Moreover, Tardyferon® was well tolerated., Competing Interests: Conflict of Interest: Dr A. LEARY works for a Regulatory Affairs Consultancy which had provided paid consultancy services to Pierre Fabre Medicament. L. BARTHE, T. CLAVEL, C. SANCHEZ,, Z. ISSIAKHEM, B. PAILLARD, J.M. EDMOND, are employees of Pierre Fabre Medicament, which provided financial and material support for the design and concept of the study, data collection, data management, data analysis and the publication of this study., (© Georg Thieme Verlag KG Stuttgart · New York.)