Absorption of low and therapeutic doses of ferric maltol, a novel ferric iron compound, in iron deficient subjects using a single dose iron absorption test

Update on iron supplementation in patients with cancer-related anemia

INTRODUCTION

Numerous clinical trials affirm the efficacy and safety of IV iron to treat cancer-related anemia (CRA). Nonetheless, evaluation and treatment of CRA remains suboptimal.

AREAS COVERED

This review summarizes CRA therapy with a focus on iron deficiency and its treatment. The literature search was conducted using the National Library of Medicine (PubMed) database from 2004 to 2024. Topics reviewed include CRA pathophysiology, laboratory diagnosis of iron deficiency, a summary of clinical trial results using IV iron to treat CRA, and safety aspects.

EXPERT OPINION

Despite overwhelming positive efficacy and safety data, IV iron remains underutilized to treat CRA. This is likely due to persistent (unfounded) concerns about IV iron safety and lack of physician awareness of newer clinical trial data. This leads to poor patient quality of life and patient exposure to anemia treatments that have greater safety risks than IV iron. Solutions to this problem include increased educational efforts and considering alternative treatment models in which other providers separately manage CRA. The recent availability of new oral iron therapy products that are effective in treating anemia of inflammation has the potential to dramatically simplify the treatment of CRA.

Oral iron therapy: Current concepts and future prospects for improving efficacy and outcomes

Iron deficiency (ID) and iron-deficiency anaemia (IDA) are global public health concerns, most commonly afflicting children, pregnant women and women of childbearing age. Pathological outcomes of ID include delayed cognitive development in children, adverse pregnancy outcomes and decreased work capacity in adults. IDA is usually treated by oral iron supplementation, typically using iron salts (e.g. FeSO4 ); however, dosing at several-fold above the RDA may be required due to less efficient absorption. Excess enteral iron causes adverse gastrointestinal side effects, thus reducing compliance, and negatively impacts the gut microbiome. Recent research has sought to identify new iron formulations with better absorption so that lower effective dosing can be utilized. This article outlines emerging research on oral iron supplementation and focuses on molecular mechanisms by which different supplemental forms of iron are transported across the intestinal epithelium and whether these transport pathways are subject to regulation by the iron-regulatory hormone hepcidin.

Deferiprone and Iron-Maltol: Forty Years since Their Discovery and Insights into Their Drug Design, Development, Clinical Use and Future Prospects

The historical insights and background of the discovery, development and clinical use of deferiprone (L1) and the maltol-iron complex, which were discovered over 40 years ago, highlight the difficulties, complexities and efforts in general orphan drug development programs originating from academic centers. Deferiprone is widely used for the removal of excess iron in the treatment of iron overload diseases, but also in many other diseases associated with iron toxicity, as well as the modulation of iron metabolism pathways. The maltol-iron complex is a recently approved drug used for increasing iron intake in the treatment of iron deficiency anemia, a condition affecting one-third to one-quarter of the world's population. Detailed insights into different aspects of drug development associated with L1 and the maltol-iron complex are revealed, including theoretical concepts of invention; drug discovery; new chemical synthesis; in vitro, in vivo and clinical screening; toxicology; pharmacology; and the optimization of dose protocols. The prospects of the application of these two drugs in many other diseases are discussed under the light of competing drugs from other academic and commercial centers and also different regulatory authorities. The underlying scientific and other strategies, as well as the many limitations in the present global scene of pharmaceuticals, are also highlighted, with an emphasis on the priorities for orphan drug and emergency medicine development, including the roles of the academic scientific community, pharmaceutical companies and patient organizations.

Long-Term Effectiveness of Oral Ferric Maltol vs Intravenous Ferric Carboxymaltose for the Treatment of Iron-Deficiency Anemia in Patients With Inflammatory Bowel Disease: A Randomized Controlled Noninferiority Trial

BACKGROUND

Iron-deficiency anemia is common in inflammatory bowel disease, requiring oral or intravenous iron replacement therapy. Treatment with standard oral irons is limited by poor absorption and gastrointestinal toxicity. Ferric maltol is an oral iron designed for improved absorption and tolerability.

METHODS

In this open-label, phase 3b trial (EudraCT 2015-002496-26 and NCT02680756), adults with nonseverely active inflammatory bowel disease and iron-deficiency anemia (hemoglobin, 8.0-11.0/12.0 g/dL [women/men]; ferritin, <30 ng/mL/<100 ng/mL with transferrin saturation <20%) were randomized to oral ferric maltol 30 mg twice daily or intravenous ferric carboxymaltose given according to each center's standard practice. The primary endpoint was a hemoglobin responder rate (≥2 g/dL increase or normalization) at week 12, with a 20% noninferiority limit in the intent-to-treat and per-protocol populations.

RESULTS

For the intent-to-treat (ferric maltol, n = 125/ferric carboxymaltose, n = 125) and per-protocol (n = 78/88) analyses, week 12 responder rates were 67% and 68%, respectively, for ferric maltol vs 84% and 85%, respectively, for ferric carboxymaltose. As the confidence intervals crossed the noninferiority margin, the primary endpoint was not met. Mean hemoglobin increases at weeks 12, 24, and 52 were 2.5 vs 3.0 g/dL, 2.9 vs 2.8 g/dL, and 2.7 vs 2.8 g/dL with ferric maltol vs ferric carboxymaltose. Treatment-emergent adverse events occurred in 59% and 36% of patients, respectively, and resulted in treatment discontinuation in 10% and 3% of patients, respectively.

CONCLUSIONS

Ferric maltol achieved clinically relevant increases in hemoglobin but did not show noninferiority vs ferric carboxymaltose at week 12. Both treatments had comparable long-term effectiveness for hemoglobin and ferritin over 52 weeks and were well tolerated.

Iron Replacement Therapy with Oral Ferric Maltol: Review of the Evidence and Expert Opinion

Iron deficiency is the most common cause of anemia globally and is frequently reported in patients with underlying inflammatory conditions, such as inflammatory bowel disease (IBD) and chronic kidney disease (CKD). Ferric maltol is a new oral iron replacement therapy designed to optimize iron absorption while reducing the gastrointestinal adverse events associated with unabsorbed free iron. Ferric maltol has been studied in clinical trials involving almost 750 adults and adolescents with iron-deficiency anemia associated with IBD, CKD, and other underlying conditions, and it has been widely used in clinical practice. It is approved for the treatment of adults with iron deficiency with or without anemia, independent of the underlying condition, and is commercially available in Europe and the United States. We review the published evidence for ferric maltol, which demonstrates consistent and clinically meaningful improvements in hemoglobin and measures of iron availability (ferritin and transferrin saturation) and shows that it is well-tolerated over long-term treatment for up to 64 weeks-an important consideration in patients with chronic underlying conditions such as IBD and CKD. We believe that ferric maltol is an effective, convenient, and well-tolerated treatment option for iron deficiency and iron-deficiency anemia, especially when long-term management of chronic iron deficiency is required. Writing support was provided by Shield Therapeutics (Gateshead, UK).

The Antimicrobial Mode of Action of Maltol and Its Synergistic Efficacy with Selected Cationic Surfactants

Maltol, mostly used as a flavoring molecule, also has various potential applications as a biomedical compound. Despite its extensive use in the food industry, maltol’s antimicrobial activity was evaluated only briefly, and was suggested to be insufficient on its own. Recently, we have shown that maltol can be used in conjunction with cationic surfactant species to receive higher activity against contaminant microorganisms. In this paper, we have broadened the antimicrobial efficacy studies and evidenced maltol’s mode of action against Gram-negative, Gram-positive bacteria, and fungi. In addition, to increase its efficacy, blends of maltol and two selected cationic surfactants, dodecyl-dimethyl-ammonium chloride (DDAC) and polyquaternium 80 (P-80), were appraised for their activity. Broad efficacy studies revealed synergistic interactions between maltol and both cationic surfactants against most of the tested microorganisms. Electron microscopy images were used to evaluate the microorganisms’ morphology following treatment, pinpointing the specific cell wall damage caused by each of the compounds. Our findings indicate that maltol’s effect on the microbial cell wall can be complemented by catalytic amounts of selected cationic surfactants to enhance and extend its activity. Such a solution can be used as a broad-spectrum preservative for personal care products in cosmetic applications.

Safety, Tolerability, and Pharmacokinetics of Oral Ferric Maltol in Children With Iron Deficiency: Phase 1 Study

Iron deficiency is common in children and can have negative effects on behavior and function. Standard oral ferrous iron replacement is poorly absorbed and can cause treatment-limiting gastrointestinal adverse events (AEs). Ferric maltol is formulated to improve gastrointestinal absorption and tolerability versus oral ferrous compounds. In adult phase 3 trials, it increased hemoglobin and iron stores versus placebo, with a gastrointestinal AE profile similar to placebo. Here, we assess different doses of ferric maltol in children with iron deficiency.

Methods

This phase 1 trial involved children of age 10 to 17 years with ferritin <30 µg/L (or <50 µg/L with transferrin saturation [TSAT] <20%). Children were randomized 1:1:1 to oral ferric maltol 7.8 mg, 16.6 mg, or 30 mg twice daily for 9 days and once on day 10. The primary outcomes were iron uptake measures (serum iron and TSAT) and population pharmacokinetic analyses.

Results

The trial included 37 children (mean age 14.0 years; baseline mean ± standard deviation ferritin 16.3 ± 8.02 µg/L). Ferric maltol increased iron uptake nondose-proportionally: serum iron and TSAT plateaued between the 2 higher doses on day 1 and were comparable across all doses on day 10. Twenty children (54%) experienced AEs (all mild/moderate, gastrointestinal 32%), with similar frequencies in each group.

Conclusions

All 3 ferric maltol doses increased iron uptake in children with iron deficiency, even over the short study duration, and were well tolerated. Nondose-dependent changes in serum iron and TSAT indicate physiologic regulation of iron uptake to meet the body's needs.

Oral Ferric Maltol for the Treatment of Iron-Deficiency Anemia in Patients With CKD: A Randomized Trial and Open-Label Extension

RATIONALE & OBJECTIVE

Iron-deficiency anemia is common in patients with chronic kidney disease (CKD) not requiring kidney replacement therapy (KRT). We evaluated effects of oral iron replacement therapy with ferric maltol in these patients.

STUDY DESIGN

Phase 3, double-blind, randomized, placebo-controlled trial (AEGIS-CKD) and open-label extension.

SETTING & PARTICIPANTS

Adults with stage 3 or 4 CKD and iron-deficiency anemia at 30 US centers.

INTERVENTION

Oral ferric maltol at 30mg or placebo twice daily for 16 weeks (2:1 randomization) followed by ferric maltol at 30mg twice daily for up to 36 weeks (all patients).

OUTCOME

Change from baseline in hemoglobin (primary end point at week 16), ferritin, transferrin saturation, and serum iron; safety.

RESULTS

167 patients were randomized (ferric maltol, n=111; placebo, n=56). At week 16, hemoglobin had increased significantly with ferric maltol versus placebo (least-squares mean difference: 0.5±0.2 [SE] g/dL; 95% CI, 0.1-0.9; P=0.01). Ferritin, transferrin saturation, and serum iron increased with ferric maltol but declined with placebo (all P<0.05). Hemoglobin levels were sustained up to week 52 in patients continuing ferric maltol and increased in patients switching from placebo to ferric maltol. The most frequent adverse events were gastrointestinal (randomized phase: 41% vs 30% [ferric maltol vs placebo]; open-label phase: 56% vs 46%, respectively). Adverse events led to treatment withdrawal in 7 patients (6%) receiving ferric maltol and 5 patients (9%) receiving placebo during double-blind treatment, and 11 patients (9%) during the open-label extension.

LIMITATIONS

Heterogeneity in baseline ferritin levels; high proportion of female participants; single-arm open-label extension.

CONCLUSIONS

Ferric maltol was associated with statistically significant (week 16) and sustained (up to week 52) increases in hemoglobin and iron indices in patients with CKD and iron deficiency, and was well tolerated during treatment for up to 52 weeks.

FUNDING

Funded by Shield Therapeutics (UK) Ltd.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT02968368.

New Era in the Treatment of Iron Deficiency Anaemia Using Trimaltol Iron and Other Lipophilic Iron Chelator Complexes: Historical Perspectives of Discovery and Future Applications

The trimaltol iron complex (International Non-proprietary Name: ferric maltol) was originally designed, synthesised, and screened in vitro and in vivo in 1980–1981 by Kontoghiorghes G.J. following his discovery of the novel alpha-ketohydroxyheteroaromatic (KHP) class of iron chelators (1978–1981), which were intended for clinical use, including the treatment of iron deficiency anaemia (IDA). Iron deficiency anaemia is a global health problem affecting about one-third of the world’s population. Many (and different) ferrous and ferric iron complex formulations are widely available and sold worldwide over the counter for the treatment of IDA. Almost all such complexes suffer from instability in the acidic environment of the stomach and competition from other dietary molecules or drugs. Natural and synthetic lipophilic KHP chelators, including maltol, have been shown in in vitro and in vivo studies to form stable iron complexes, to transfer iron across cell membranes, and to increase iron absorption in animals. Trimaltol iron, sold as Feraccru or Accrufer, was recently approved for clinical use in IDA patients in many countries, including the USA and in EU countries, and was shown to be effective and safe, with a better therapeutic index in comparison to other iron formulations. Similar properties of increased iron absorption were also shown by lipophilic iron complexes of 8-hydroxyquinoline, tropolone, 2-hydroxy-4-methoxypyridine-1-oxide, and related analogues. The interactions of the KHP iron complexes with natural chelators, drugs, metal ions, proteins, and other molecules appear to affect the pharmacological and metabolic effects of both iron and the KHP chelators. A new era in the treatment of IDA and other possible clinical applications, such as theranostic and anticancer formulations and metal radiotracers in diagnostic medicine, are envisaged from the introduction of maltol, KHP, and similar lipophilic chelators.

Ferric maltol Real-world Effectiveness Study in Hospital practice (FRESH): clinical characteristics and outcomes of patients with inflammatory bowel disease receiving ferric maltol for iron-deficiency anaemia in the UK

Objective

To assess outcomes in patients with iron-deficient inflammatory bowel disease (IBD) treated with ferric maltol in UK real-world practice.

Design/Method

This observational, multicentre, retrospective cohort study included adults with IBD and iron-deficiency anaemia (IDA; haemoglobin ≥95 to <120 g/L (women) or ≥95 to <130 g/L (men) plus serum ferritin <30 µg/L or transferrin saturation <20%) who received ferric maltol. Data were extracted from patient records. The primary analysis was the proportion of patients with normalised haemoglobin (≥120 g/L (women); ≥130 g/L (men)) over 12 weeks. Iron indices and safety were assessed.

Results

Thirty of 59 patients had data for the primary outcome, 19 of whom (63%) achieved haemoglobin normalisation at week 12. Mean±SD haemoglobin was 127±16 g/L at week 12 (increase of 14±17 g/L from baseline). Overall, 27 patients achieved haemoglobin normalisation by the end of the observation period; mean±SD time to normalisation was 49.5±25.6 days. Nine of 17 patients had normalised serum ferritin (30–300 µg/L) at week 12, and 16 patients had normalised ferritin at the end of the observation period; mean±SD time to normalisation was 71.3±27.6 days. Twenty-four adverse events occurred in 19 patients (32%); most frequent adverse events were abdominal pain or discomfort (n=9) and constipation (n=3).

Conclusion

Ferric maltol increases haemoglobin and iron indices and is generally well tolerated in patients with IBD and IDA treated in clinical practice. These real-world data support findings from randomised controlled trials.

Novel Oral Iron Therapies for Iron Deficiency Anemia in Chronic Kidney Disease

Iron deficiency anemia (IDA) is a frequent complication of chronic kidney disease (CKD) and is associated with adverse outcomes in these patients. Patients with CKD and IDA remain largely undertreated. Conventional oral iron agents are insufficiently effective due to poor absorption and cause gastrointestinal side effects; thus, novel oral iron preparations are needed. This article covers current treatment guidelines for patients with anemia and CKD and clinical trial data for iron-repletion agents currently in use, as well as for novel oral iron therapies in development. Ferric citrate, a novel oral iron-repletion agent approved for patients with non-dialysis-dependent CKD and IDA, demonstrated improvements in hemoglobin levels and iron parameters, with good tolerability in patients with non-dialysis-dependent CKD. When used as a phosphate binder, ferric citrate also improves hemoglobin and iron parameters in dialysis-dependent CKD, but additional trials are needed to evaluate its efficacy as an iron-repletion agent in this setting. Other novel oral iron preparations in development for IDA in patients with CKD include ferric maltol, which is approved in Europe and the United States for IDA in adult patients, and sucrosomial iron, which has been evaluated in IDA associated with CKD and several other clinical settings.

Randomized Open-Label Phase 1 Study of the Pharmacokinetics of Ferric Maltol in Inflammatory Bowel Disease Patients with Iron Deficiency

BACKGROUND

Iron deficiency anemia (IDA) is a common complication of inflammatory bowel disease (IBD). Oral ferric maltol improves and normalizes hemoglobin (Hb) in patients with IBD.

AIM

This open-label, randomized Phase 1 study evaluated the pharmacokinetics of ferric maltol and its effect on iron indices in IBD patients with iron deficiency (with or without anemia).

METHODS

Iron deficient adult IBD patients received ferric maltol 30, 60, or 90 mg twice daily during an 8-day period. Pharmacokinetics and iron uptake were assessed on days 1 and 8.

RESULTS

Twenty-four patients were included: 13 with Crohn's disease and 11 with ulcerative colitis (mean age 39 years; 67 % female, mean Hb 13.0 g/dL; mean reticulocyte Hb content (CHr) 31.9 pg; mean ferritin 13.9 µg/L). Plasma maltol and maltol glucuronide increased rapidly at all doses, reaching maximum plasma concentration (C _max) 1.0-1.5 h post-dose and declining to baseline after 3-6 h. Maltol and maltol glucuronide exposure (area under the concentration-time curve; AUC) appeared dose proportional with twice-daily dosing, with higher exposure to maltol glucuronide vs. maltol. Mean day 8/day 1 ratios for C _max and AUC_0-t indicated no accumulation after 7 days of twice-daily dosing. Serum iron and transferrin saturation (TSAT) increased with all doses (maximum values at 1.5-3.0 h post-dose). Serum ferritin and CHr increased by day 8, with greater improvements with 60 and 90 mg twice-daily doses than with 30 mg twice-daily doses.

CONCLUSIONS

The key constituents of ferric maltol showed predictable pharmacokinetics, with no accumulation over 7 days and increased iron uptake and storage over time at 30-90 mg twice-daily doses.

Ferric maltol therapy for iron deficiency anaemia in patients with inflammatory bowel disease: long-term extension data from a Phase 3 study

BACKGROUND

Ferric maltol was effective and well-tolerated in iron deficiency anaemia patients with inflammatory bowel disease during a 12-week placebo-controlled trial.

AIM

To perform a Phase 3 extension study evaluating long-term efficacy and safety with ferric maltol in inflammatory bowel disease patients in whom oral ferrous therapies had failed to correct iron deficiency anaemia.

METHODS

After 12 weeks of randomised, double-blind treatment, patients with iron deficiency anaemia and mild-to-moderate ulcerative colitis or Crohn's disease received open-label ferric maltol 30 mg b.d. for 52 weeks.

RESULTS

111 patients completed randomised treatment and 97 entered the open-label ferric maltol extension. In patients randomised to ferric maltol ('continued'; n = 50), mean ± s.d. haemoglobin increased by 3.07 ± 1.46 g/dL between baseline and Week 64. In patients randomised to placebo ('switch'; n = 47), haemoglobin increased by 2.19 ± 1.61 g/dL. Normal haemoglobin was achieved in high proportions of both continued and switch patients (89% and 83% at Week 64, respectively). Serum ferritin increased from 8.9 μg/L (baseline) to 26.0 μg/L (Week 12) in ferric maltol-treated patients, and to 57.4 μg/L amongst all patients at Week 64. In total, 80% of patients reported ≥1 adverse event by Week 64. Adverse events considered related to ferric maltol were recorded in 27/111 (24%) patients: 8/18 discontinuations due to adverse events were treatment-related. One patient was withdrawn due to increased ulcerative colitis activity.

CONCLUSIONS

Normal haemoglobin was observed in ≥80% of patients from weeks 20-64 of long-term ferric maltol treatment, with concomitant increases in iron storage parameters. Ferric maltol was well-tolerated throughout this 64-week study.

Ferric maltol (ST10): a novel oral iron supplement for the treatment of iron deficiency anemia in inflammatory bowel disease

INTRODUCTION

Iron deficiency anemia affects up to three quarters of patients with inflammatory bowel disease (IBD). It can significantly impact the quality of life and the ability to work by impairing physical, emotional, and cognitive functioning. The etiology of iron deficiency anemia is multifactorial and oral or intravenous iron replacement is necessary. However, oral iron supplements are often discontinued prematurely due to poor tolerability or insufficient efficacy. Moreover, intravenous supplementation is inconvenient, associated with potentially serious safety risks, and a burden on healthcare resources.

AREAS COVERED

Ferric maltol is a novel ferric iron compound with potential use as an oral therapy for iron deficiency anemia. This overview explains how the molecule's design impacts clinical outcomes and summarizes available clinical data (ranging from early comparisons with ferrous sulfate to randomized, placebo-controlled, Phase III data in patients with IBD known to be intolerant of oral ferrous products).

EXPERT OPINION

Ferric maltol offers the ability to treat iron deficiency anemia in mild-to-moderate IBD without resorting to intravenous therapy, even in those who are intolerant of oral ferrous products. This clinical benefit has the potential to change treatment pathways and increase choice, not only in IBD but also perhaps in many areas beyond gastroenterology.

Ferric maltol is effective in correcting iron deficiency anemia in patients with inflammatory bowel disease: results from a phase-3 clinical trial program

BACKGROUND

Iron deficiency anemia (IDA) is frequently seen in inflammatory bowel disease. Traditionally, oral iron supplementation is linked to extensive gastrointestinal side effects and possible disease exacerbation. This multicenter phase-3 study tested the efficacy and safety of ferric maltol, a complex of ferric (Fe) iron with maltol (3-hydroxy-2-methyl-4-pyrone), as a novel oral iron therapy for IDA.

METHODS

Adult patients with quiescent or mild-to-moderate ulcerative colitis or Crohn's disease, mild-to-moderate IDA (9.5-12.0 g/dL and 9.5-13.0 g/dL in females and males, respectively), and documented failure on previous oral ferrous products received oral ferric maltol capsules (30 mg twice a day) or identical placebo for 12 weeks according to a randomized, double-blind, placebo-controlled study design. The primary efficacy endpoint was change in hemoglobin (Hb) from baseline to week 12. Safety and tolerability were assessed.

RESULTS

Of 329 patients screened, 128 received randomized therapy (64 ferric maltol-treated and 64 placebo-treated patients) and comprised the intent-to-treat efficacy analysis: 55 ferric maltol patients (86%) and 53 placebo patients (83%) completed the trial. Significant improvements in Hb were observed with ferric maltol versus placebo at weeks 4, 8, and 12: mean (SE) 1.04 (0.11) g/dL, 1.76 (0.15) g/dL, and 2.25 (0.19) g/dL, respectively (P < 0.0001 at all time-points; analysis of covariance). Hb was normalized in two-thirds of patients by week 12. The safety profile of ferric maltol was comparable with placebo, with no impact on inflammatory bowel disease severity.

CONCLUSIONS

Ferric maltol provided rapid clinically meaningful improvements in Hb and showed a favorable safety profile, suggesting its possible use as an alternative to intravenous iron in IDA inflammatory bowel disease.

Evaluation of ferric and ferrous iron therapies in women with iron deficiency anaemia

Introduction. Different ferric and ferrous iron preparations can be used as oral iron supplements. Our aim was to compare the effects of oral ferric and ferrous iron therapies in women with iron deficiency anaemia. Methods. The present study included 104 women diagnosed with iron deficiency anaemia after evaluation. In the evaluations performed to detect the aetiology underlying the iron deficiency anaemia, it was found and treated. After the detection of the iron deficiency anaemia aetiology and treatment of the underlying aetiology, the ferric group consisted of 30 patients treated with oral ferric protein succinylate tablets (2 × 40 mg elemental iron/day), and the second group consisted of 34 patients treated with oral ferrous glycine sulphate tablets (2 × 40 mg elemental iron/day) for three months. In all patients, the following laboratory evaluations were performed before beginning treatment and after treatment. Results. The mean haemoglobin and haematocrit increases were 0.95 g/dL and 2.62% in the ferric group, while they were 2.25 g/dL and 5.91% in the ferrous group, respectively. A significant difference was found between the groups regarding the increase in haemoglobin and haematocrit values (P < 0.05). Conclusion. Data are submitted on the good tolerability, higher efficacy, and lower cost of the ferrous preparation used in our study.

Clinical pharmacokinetics of ferric natural protein in iron-deficient females

Although iron therapy is very common, few studies have assessed iron absorption or iron kinetics in general, particularly with Fe(3+). This was the primary objective of this study, with assessment of tolerance as a secondary objective. Eight nonsmoking iron-deficient females without other associated pathologies, with an average age of 21.62 +/- 1.69 years, were studied. The diagnosis of iron deficiency was established by determination of sideraemia (28.7 +/- 13.5 microg/dl), iron binding capacity (380.5 +/- 70.2 microg/dl) and ferritin (5 +/- 1.4 microg/L) on the prestudy visit. The women remained in the Phase I Unit during days 0, 1, 2 and 3 of the study. A serum iron concentration curve was obtained daily from blood samples drawn at 0, 1, 2, 4, 6, 8 and 12 hours postdose. Therapy with ferric natural protein (ferrimannitol ovoalbumin) 40mg twice daily was started on day 1 of the study and continued for 30 days. The following parameters were evaluated: area under the curve (AUC(0-12h)), peak iron concentration (C(max)) and time to reach peak concentration (t(max)). Serum iron concentration-time curves were practically flat on day 0, but showed an increase following ferric therapy (Friedman, p < 0.05), confirming the usefulness of the postabsorption test and good absorption of ferric iron (Fe(3+)). The increase in AUC (314.65 +/- 67.9 to 1174.44 +/- 1071.8 microg/dl.h) and C(max) (49 +/- 24.4 to 146 +/- 101.9 microg/dl) from day 1 and the correlation between both parameters (r(2) > 0.85, p </= 0.008) supported the use of either parameter. The t(max) ranged from 4 to 6 hours. Ferric therapy was well tolerated by all patients. This study shows that ferric iron contained in this preparation is well absorbed and provides a satisfactory method for evaluation of iron absorption.

The identification of antioxidants in dark soy sauce

Soy sauce is a traditional fermented seasoning in Asian countries, that has high antioxidant activity in vitro and some antioxidant activity in vivo. We attempted to identify the major antioxidants present, using the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay as a guide. 3-Hydroxy-2-methyl-4H-pyran-4-one (maltol) was one of several active compounds found in an ethyl acetate extract of dark soy sauce (DSS) and was present at millimolar concentrations in DSS. However, most of the antioxidant activity was present in colored fractions, two of which (CP1 and CP2) were obtained by gel filtration chromatography. Their structural characteristics based on nuclear magnetic resonance (NMR) and electrospray-ionization time-of-flight mass spectrometry (ESI-TOF-MS) analysis suggest that carbohydrate-containing pigments such as melanoidins are the major contributors to the high antioxidant capacity of DSS.

The validation of using serum iron increase to measure iron absorption in human subjects

The objectives of the present study were to study the correlation between the change in serum Fe and Fe absorption when administering 100 mg Fe (as FeSO4) orally, and to study the correlation between the absorption from a 3 mg and a 100 mg Fe (as FeSO4) dose. The study was conducted in a group of eleven male blood donors, without any evident infection, who had given blood 8 weeks before the study. On three consecutive mornings the subjects were served a wheat roll fortified with Fe. On the first 2 d the roll was fortified with 3 mg Fe labelled with 59Fe; on day 3 the roll was fortified with 100 mg Fe labelled with 55Fe. The serum Fe response to the 100 mg dose was followed for 6 h. Fe absorption was measured by whole-body counting. High correlations were seen between the absorption of Fe and the change in serum Fe after 100 mg Fe (r2 0·94, P>0·001), between the absorption from 3 mg and 100 mg Fe (r2 0·88, P>0·001), and between the absorption from 3 mg Fe and change in serum Fe after 100 mg Fe (r2 0·90, P>0·001). This strengthens the evidence that it is possible to use the change in serum Fe as a measure of Fe absorption, e.g. when establishing the relative bioavailability for Fe powders. The results also imply that the induced serum Fe increase following 100 mg Fe added to a food could predict the Fe absorption of a small dose of Fe added to the same meal.

Assessment of iron absorption from ferric trimaltol

Therapeutic iron compounds have limited absorption and often have side-effects, which limits patient compliance. Iron trimaltol is a novel, stable complex, formed between ferric iron (Fe3+) and maltol (3-hydroxy-2-methyl-4-pyrone), and is effective in the treatment of iron deficiency anaemia with few side-effects. However, the kinetics of iron absorption from ferric trimaltol and the reliability of normal colorimetric analysis in detecting iron absorbed from this complex have not been established. We measured increases in serum iron levels in 12 volunteers following oral challenge with four different pharmaceutical formulations of ferric trimaltol in a double-blind, cross-over, randomized study. The conventional colorimetric method for detecting serum iron was compared with thermal analyses after trichloroacetic acid (TCA) treatment of serum. Measurements of serum iron levels by TCA treatment and thermal analysis closely agreed with measurements by colorimetry. For all formulations, serum iron levels peaked at 90 min with a plateau of at least 5 h [mean (standard deviation) peak absorption 8.3% (6.3%) of ingested dose, n=48]. Absorption of iron, based on peak serum values or area under the serum curve, was not different for the four formulations (n=12 each) and correlated with the individual's iron status, as assessed by serum ferritin values (r = -0.6; P < 0.001). Normal colorimetry is suitable for analysis of serum iron levels following ingestion of ferric trimaltol. There is rapid and sustained absorption of iron from ferric trimaltol and, as with ferrous iron, uptake appears to be controlled through normal mechanisms of iron acquisition that depend upon body iron stores.

Low-dose oral iron absorption test: establishment of a reference interval

The low-dose oral iron absorption test (OIAT), a possible test for iron deficiency, is based on the fact that intestinal iron absorption is higher in iron-deficient subjects than in those with normal or increased iron stores. The aims of this study were to establish a reference interval for the OIAT, to evaluate five different ways of presenting the results, and to advocate for the use of one of these methods. OIAT was performed in 122 healthy volunteers, 3 of whom were excluded as a result of technical difficulties. The volunteers were given 10 mg of oral iron sulphate at 0900 h on an empty stomach. S-iron was measured just before iron consumption, and after 1, 2 and 3 h. The maximum increase in S-iron during the test, presented as Cmax (micromol l(-1)), was higher in females (5 [median]; 3 and 7 [1st and 3rd quartiles]; 0-34 [range]) than in males (3; 1 and 5; 0-13) (p<0.001 Mann Whitney U-test). Furthermore, Cmax was significantly higher in females aged 22 44 years than in all other age groups (males and females), but did not fluctuate significantly with age in males. Cmax was higher in premenopausal than in postmenopausal females (6; 5 and 10; 0-34 and 4; 2 and 5; 0-12, respectively) (p <0.01 Mann Whitney U-test). In conclusion, iron absorption assessed by the OIAT was higher in premenopausal females than in postmenopausal females and males. We suggest reference intervals of 0-34 micromol l(-1) in premenopausal females, and 0-11 micromol l(-1) in all other persons, i.e. males and postmenopausal females.

Absorption of iron from ferric hydroxypyranone complexes

The absorption of 59Fe from preparations of FeSO4 and the ferric hydroxypyranone complexes maltol and ethyl maltol was studied by whole-body counting in normal subjects and patients with Fe deficiency. Fe in the Fe3+ complexes was in general absorbed almost as well as Fe2+. It is concluded that the absorption of Fe3+ from hydroxypyranone complexes is much greater than that from simple Fe3+ salts; this may prove an efficient and less toxic form of Fe for the treatment of deficiency.