Bioequivalence decision for nanoparticular iron complex drugs for parenteral administration based on their disposition.

Although parenteral iron products have been established to medicinal use decades before, their structure and pharmacokinetic properties are not fully characterized yet. With its' second reflection paper on intravenous iron-based nano-colloidal products (EMA/CHMP/SWP/620008/2012) the European Medicine Agency provided an extensive catalogue of methods for quality, non-clinical and pharmacokinetic studies for the comparison of nano-sized iron products to an originator (EMA, 2015). For iron distribution studies, the reflection paper assumed the use of rodents. In our tests, we used a turkey fetus model to investigate time dependent tissue concentrations in pharmacological and toxicological relevant tissues liver, heart and kidney. We found turkey embryos to be a suitable alternative to rodents with high discriminatory sensitivity. Clear differences were found between equimolar doses of iron products with hydroxyethyl amylopectin, sucrose, dextrane and carboxymaltose shell. A linear dose dependency for the tissue accumulation was also demonstrated.

Differential Effect of Acute Iron Overload on Oxidative Status and Antioxidant Content in Regions of Rat Brain.

The hypothesis of this study is that the cerebral cortex, hippocampus, and striatum of the rat brain are differentially affected in terms of oxidative stress and antioxidant capacity by acute Fe overload because Fe is distributed in a heterogeneous fashion among different regions and cells of the brain. The effects on the lipophilic and hydrophilic cellular environment were compared between regions and with the whole brain. A single dose of Fe-dextran increased Fe deposits, reaching a maximum after 6 hr. Both in whole brain and in cortex region, the ascorbyl/ascorbate content ratio was increased after 6 hr of Fe administration, while in striatum and hippocampus, there was no significant changes after Fe overload. Total thiol content decreased in whole brain and cortex, while there were no significant changes in striatum and hippocampus after Fe overload. The content of α-tocopherol (α-T), whether measured in the whole brain or in the isolated regions, did not change following Fe treatment. Lipid radical (LR•) generation rate after Fe-dextran overload only increased in the cortex region. The LR•/α-T content ratio was increased by Fe treatment in cortex but not in the whole brain, striatum, or hippocampus, in agreement with the study tested hypothesis.

Iron toxicity mediated by oxidative stress enhances tissue damage in an animal model of diabetes.

Although iron is a first-line pro-oxidant that modulates clinical manifestations of various systemic diseases, including diabetes, the individual tissue damage generated by active oxidant insults has not been demonstrated in current animal models of diabetes. We tested the hypothesis that oxidative stress is involved in the severity of the tissues injury when iron supplementation is administered in a model of type 1 diabetes. Streptozotocin (Stz)-induced diabetic and non-diabetic Fischer rats were maintained with or without a treatment consisting of iron dextran ip at 0.1 mL day(-1) doses administered for 4 days at intervals of 5 days. After 3 weeks, an extensive increase (p < 0.001) in the production of reactive oxygen species (ROS) in neutrophils of the diabetic animals on iron overload was observed. Histological analysis revealed that this treatment also resulted in higher (p < 0.05) tissue iron deposits, a higher (p < 0.001) number of inflammatory cells in the pancreas, and apparent cardiac fibrosis, as shown by an increase (p < 0.05) in type III collagen levels, which result in dysfunctional myocardial. Carbonyl protein modification, a marker of oxidative stress, was consistently higher (p < 0.01) in the tissues of the iron-treated rats with diabetes. Moreover, a significant positive correlation was found between ROS production and iron pancreas stores (r = 0.42, p < 0.04), iron heart stores (r = 0.54, p < 0.04), and change of the carbonyl protein content in pancreas (r = 0.49, p < 0.009), and heart (r = 0.48, p < 0.02). A negative correlation was still found between ROS production and total glutathione content in pancreas (r = -0.50, p < 0.03) and heart (r = -0.45, p < 0.04). In conclusion, our results suggest that amplified toxicity in pancreatic and cardiac tissues in rats with diabetes on iron overload might be attributed to increased oxidative stress.

The role of iron supplementation during epoietin treatment for cancer-related anemia.

UNLABELLED: Cancer-related anemia is common and multifactorial in origin. Functional iron deficiency (FID) is now recognized as a cause of iron-restricted erythropoiesis and may be one of the major reasons for lack of response to treatment with Erythropoietic Stimulating Agents (ESAs). Numerous studies have shown that intravenous (IV), but not oral, iron therapy effectively provides sufficient iron for optimal erythropoiesis in anemic patients with chronic renal disease receiving ESA therapy. The use of IV iron has also been suggested in the cancer setting. Six recent studies have tested this assumption and are summarized in this review. Four formulations of IV iron are available in Europe, with different pharmacokinetics, iron bioavailability, and risk of acute adverse drug reactions. CONCLUSION: Limited iron stores and FID are common causes of response failure during ESA treatment in cancer patients and should be diagnosed. There is now substantial scientific support for the use of IV iron supplementation to improve response and this has been acknowledged in international and national guidelines. Prospective long-term data on the safety of IV iron in this setting are still awaited. Recommendations concerning the optimal formulation, doses, and schedule of iron supplementation to ESA treatment in cancer-related anemia are provisional awaiting data from prospective, randomized trials.

T2 ∗ Relaxation Time Obtained from Magnetic Resonance Imaging of the Liver Is a Useful Parameter for Use in the Construction of a Murine Model of Iron Overload.

Aim: Iron overload is a life-threatening disorder that can increase the risks of cancer, cardiovascular disease, and liver cirrhosis. There is also a risk of iron overload in patients with chronic kidney disease. In patients with renal failure, iron storage is increased due to inadequate iron utilization associated with decreased erythropoiesis and also to the inflammatory status. To evade the risk of iron overload, an accurate and versatile indicator of body iron storage in patients with iron overload is needed. In this study, we aimed to find useful iron-related parameters that could accurately reflect body iron storage in mice in order to construct a murine model of iron overload. Methods: To select an appropriate indicator of body iron status, a variety of parameters involved in iron metabolism were evaluated. Noninvasively measured parameters were R1, R2, and R2 ∗ derived from magnetic resonance imaging (MRI). Invasively measured parameters included serum hepcidin levels, serum ferritin levels, and liver iron contents. Histopathological analysis was also conducted. Results/Conclusion: Among the several parameters evaluated, the MRI T2 ∗ relaxation time was able to detect iron storage in the liver as sensitively as serum ferritin levels. Moreover, it is expected that using an MRI parameter will allow accurate evaluation of body iron storage in mice over time.

Antioxidant-mediated effects in a gerbil model of iron overload.

INTRODUCTION: Iron cardiomyopathy is a lethal complication of transfusion therapy in thalassemia major. Nutritional supplements decreasing cardiac iron uptake or toxicity would have clinical significance. Murine studies suggest taurine may prevent oxidative damage and inhibit Ca2+-channel-mediated iron transport. We hypothesized that taurine supplementation would decrease cardiac iron-overloaded toxicity by decreasing cardiac iron. Vitamin E and selenium served as antioxidant control. METHODS: Animals were divided into control, iron, taurine, and vitamin E/selenium groups. Following sacrifice, iron and selenium measurements, histology, and biochemical analyses were performed. RESULTS: No significant differences were found in heart and liver iron content between treatment groups, except for higher hepatic dry-weight iron concentrations in taurine-treated animals (p < 0.03). Serum iron increased with iron loading (751 +/- 66 vs. 251 +/- 54 microg/dl, p < 0.001) and with taurine (903 +/- 136 microg/dl, p = 0.03). CONCLUSION: Consistent with oxidative stress, iron overload increased cardiac malondialdehyde levels, decreased heart glutathione peroxidase (GPx) activity, and increased serum aspartate aminotransferase. Taurine ameliorated these changes, but only significantly for liver GPx activity. Selenium and vitamin E supplementation did not improve oxidative markers and worsened cardiac GPx activity. These results suggest that taurine acts primarily as an antioxidant rather than inhibiting iron uptake. Future studies should illuminate the complexity of these results.

The design, synthesis, and evaluation of organ-specific iron chelators.

A series of iron chelators, three (S)-4,5-dihydro-2-(2-hydroxyphenyl)-4-methyl-4-thiazolecarboxylic acid (DADFT) and three (S)-4,5-dihydro-2-(2-hydroxyphenyl)-4-thiazolecarboxylic acid (DADMDFT) analogues are synthesized and assessed for their lipophilicity (log Papp), iron-clearing efficiency (ICE) in rodents and iron-loaded primates (Cebus apella), toxicity in rodents, and organ distribution in rodents. The results lead to a number of generalizations useful in chelator design strategies. In rodents, while log Papp is a good predictor of a chelator's ICE, chelator liver concentration is a better tool. In primates, log Papp is a good predictor of ICE, but only when comparing structurally very similar chelators. There is a profound difference in toxicity between the DADMDFT and DADFT series: DADMDFTs are less toxic. Within the DADFT family of ligands, the more lipophilic ligands are generally more toxic. Lipophilicity can have a profound effect on ligand organ distribution, and ligands can thus be targeted to organs compromised in iron overload disease, for example, the heart.

The treatment of restless legs syndrome with intravenous iron dextran.

BACKGROUND AND PURPOSE: To evaluate the safety and efficacy of a single 1000 mg iron infusion in treating Restless Legs Syndrome (RLS). PATIENTS AND METHODS: A single 1000 mg intravenous (IV) [Am J Med Sci 31 (1999) 213] infusion of iron dextran was evaluated in an open-label study. Primary outcomes of efficacy were symptom severity assessed by global rating scale and periodic leg movements in sleep (PLMS) at 2 weeks post-infusion. Secondary outcomes included total sleep time (TST), hours/day of RLS symptoms, and changes in magnetic resonance imaging (MRI)-determined iron concentrations in the substantia nigra. Primary safety measures were reported adverse events and monthly serum ferritin levels. RESULTS: IV iron therapy significantly improved the mean global RLS symptom severity, TST, hours with RLS symptoms and PLMS, but on an individual basis failed to produce any response in 3 of the 10 subjects who were fully treated. Brian iron concentrations at 2 weeks post-infusion as determined by MRI were increased in the substantia nigra and prefrontal cortex. Serum ferritin levels showed a greater than predicted rapid linear decrease. Side effects were mild, except in one subject who developed an acute allergic reaction. CONCLUSIONS: The results in this study provide valuable information for future studies, but the efficacy and safety of IV iron treatment for RLS remain to be established in double-blind studies. The serum ferritin results suggest that greater than expected iron loss occurs after IV iron loading.

A study of erythropoiesis and iron metabolism in the rabbit in vivo. II. Dependence of the response on iron storage and transport.

Rabbits subjected to a daily bloodletting schedule of 10 ml blood per kg body weight increase four- or fivefold their erythropoietic production compared to normal non-bled animals. The maximum response they can reach under these conditions mobilizes more than 9 mg of iron per day per rabbit into hemoglobin. When fed ad libitum with their regular diet, they do not need any further iron supplement for full erythropoiesis. The experimental increment in iron body stores and/or serum iron levels does not enhance their erythropoietic response, demonstrating that iron is not rate limiting under the conditions studied. Furthermore, although serum iron levels are elevated onefold in the controls under chronic anemia with respect to non-bled animals, the concentration of serum transferrin is only slightly increased; hence, the iron saturation of this protein changes from a 50% to an 80% level. In the absence of an extra supplement of iron, rabbits subjected to chronic bloodletting show no signs of body iron depletion, as judged by their continuous macrocytic RBC production.

The molecular formula and proposed structure of the iron-dextran complex, imferon.

The first iron-dextran complex was discovered in 1953, when we attempted to synthesize an analog of ferritin, by substituting polysaccharide for its protein shell. This new complex soon became the most widely used parental therapy for hypochromic anemia in humans. No molecular formula has been proposed, but Cox has attributed an outline structure to it. The present article proposes a structure greatly different from the Cox model, by having a polynuclear beta-ferric oxyhydroxide core, closely similar or identical to Akaganeite, chelated firmly by an encircling framework of dextran gluconic acid chains and surrounded by a removable outer sheath of colloidal dextran gluconic acid. The molecular weight of the iron-dextran core molecule, including its chelated framework, has been determined by gel filtration and analysis and its molecular formula (1.3) calculated. Also, these new data and existing electron photomicrographic, X-ray diffraction and crystallographic studies, have enabled a molecular weight, formula, and model structure to be proposed for its complex (2), which includes the outer sheath. The 480 iron atoms in both the core molecule and its sheathed complex are close to the number calculated from the core's unit cell dimensions and volume.

[Dextran-ferrite distribution in the body of animals in a nonuniform permanent magnetic field]. / Raspredelenie dekstran-ferrita v organizme zhivotnykh v neodnorodnom postoiannom magnitnom pole.

Dextran-ferrite (DF) was injected via the femoral artery to the dogs and followed by local magnetization (induction 0.3 T, grade 0.024 T/cm). It has been shown that the local retention of the iron in some tissues of the leg was 3-5 times as high as the control. The magnetization did not increase the local retention of the iron after intravenous injection of DF to mice and rabbits.

Absorption of iron dextran from the peritoneal cavity of rats.

We investigated the absorption rate and acute toxicities of intraperitoneal iron dextran in rats. Eighteen Sprague-Dawley rats were divided into three groups (n = 6). The animals were given standard 1.5% Dianeal (group 1) or 1.5% Dianeal containing iron in a concentration of 2 mg/L (group 2) or 10 mg/L (group 3) as iron dextran. First, a predialysis blood sample was obtained, and 25 mL of the designated dialysis solution was instilled into the peritoneal cavity. After a 6-hour cycle the dialysate was drained, and a postdialysis blood sample and specimen of the peritoneum were obtained. The iron concentrations of the dialysis solution, the dialysate, and both serum samples were determined. Histological samples were processed by hematoxylin and eosin and Prussian blue stain. Results of the iron concentration (mg/L) of the dialysis solution, the dialysate, and the percent of the absorbed iron were as follows: group 1: 0.00, 0.20 +/- 0.15, N/A; group 2: 2.24, 0.66 +/- 2.8, 73.8 +/- 11.0; group 3: 9.84, 2.12 +/- 0.62, 80.8 +/- 5.7. The serum iron concentration did not change. No abnormal findings were found histologically. More than 70% of the iron dextran was absorbed from the peritoneal cavity of the rats during a 6-hour peritoneal dialysis exchange. Intraperitoneal iron dextran may be an alternative route of iron delivery.

Minimally invasive transdermal delivery of iron-dextran.

Iron deficiency is one of the most prevalent and serious health issues among people all over the world. Iron-dextran (ID) colloidal solution is one among the very few US Food and Drug Administration (FDA)-approved iron sources for parenteral administration of iron. Parenteral route does not allow frequent administration because of its invasiveness and other associated complications. The main aim of this project was to investigate the plausibility of transdermal delivery of ID facilitated by microneedles, as an alternative to parenteral iron therapy. In vitro permeation studies were carried out using freshly excised hairless rat abdominal skin in a Franz diffusion apparatus. Iron repletion studies were carried out in hairless anemic rat model. The anemic rats were divided into intact skin (control), microneedle pretreated, and intraperitoneal (i.p.) groups depending on the mode of delivery of iron. The hematological parameters were measured intermittently during treatment. There was no improvement in the hematological parameters in case of control group, whereas, in case of microneedle pretreated and i.p. group, there was significant improvement within 2-3 weeks. The results suggest that microneedle-mediated delivery of ID could be developed as a potential treatment method for iron-deficiency anemia.

Comparative toxicity and cell-tissue distribution study on nanoparticular iron complexes using avian embryos and HepG2-cells.

In this study the toxicity and intracellular availability of iron from iron dextran (FeD), iron sucrose (FeS), and iron gluconate (FeG) was compared in organs of avian (turkey) embryos and in isolated cells (HepG2) in cell culture. Iron uptake was more pronounced in embryonic liver than in renal tissue. Cellular iron uptake in liver and kidney was more or less similar for the different compounds. Only some experiments showed slightly greater iron concentrations in liver and kidney with FeG compared with FeD and FeS. Significant differences were found in the survival ratios of the eggs and the embryo weights depending on the type of iron complex administered. The rank order of toxicities was FeG>FeS>FeD. Iron accumulation in HepG2-cells was extremely high with FeS and FeG, whereas FeD did not lead to a relevant iron uptake by HepG2 cells. The excessively high iron content of the cells is an in vitro phenomenon found neither in the in ovo model with the turkey embryos nor in the clinical use of the compounds. The rank order of toxicities in HepG2 cells was FeS>FeG>FeD. Iron uptake in cell culture does not reflect the in vivo situation. The in ovo model is more suitable to assess the cellular iron uptake and iron toxicity in cells and tissues than the in vitro model. In both in ovo and in vitro experiments, FeD seemed to be superior in terms of toxicity.

Transferrin saturation with intravenous irons: an in vitro study.

BACKGROUND: Iron deficiency anemia in chronic kidney disease is commonly treated with one of three intravenous irons-iron dextran, iron sucrose, or iron gluconate. Substantial pharmacologic differences between drugs exist, but their ability to saturate transferrin has not been compared. Drugs that may lead to rapid transferrin saturation may lead to greater efficacy but also increased toxicity if transferring-mediated uptake of iron is the basis of this toxicity. METHODS: We studied the in vitro ability of the three intravenous irons to donate iron to transferrin. Transferrin saturation was studied by direct visualization of the transferrin bands by urea polyacrylamide gel electrophoresis (PAGE), as well as a functional assay that evaluated the ability of iron to half saturate transferrin in a dose-dependent (0 to 100 microg/mL) and time-dependent (15 to 180 min) manner. Half-maximal dose (EC(50)) of iron needed to saturate transferrin was evaluated. RESULTS: Nondextran irons were able to saturate transferrin in a dose-dependent and time-dependent manner. There was more rapid transferrin saturation with iron gluconate compared to iron sucrose. The slope of the EC(50) versus dose iron gluconate titration curve was -0.021 nmol/microg/mL (95% CI -0.025 to -0.017, P < 0.0001), for iron sucrose -0.006 nmol/microg/mL (95% CI -0.010 to -0.002, P= 0.002), and for iron dextran -0.001 nmol/microg/mL (95% CI -0.004 to 0.003, P > 0.2). The least square mean EC(50) computed for mean iron concentration was 5.95 nmol for iron gluconate (95% CI 5.82 to 6.08), 6.73 nmol for iron sucrose (95% CI 6.59 to 6.86), and 7.24 nmol for iron dextran (95% CI 7.11 to 7.38). Similar results were seen for the time-dependent transferrin saturation (drug x time interaction, F 6.0, P < 0.01). Urea PAGE analysis showed similar results as the functional assay. CONCLUSION: Substantial heterogeneity in direct iron transfer from iron pharmaceuticals in vitro suggests that differences may exist in safety and efficacy of these drugs in vivo. In vivo studies are needed to compare the safety and efficacy of existing nondextran parenteral irons to better define the therapeutic ratio.

The role of fetal breathing motions compared with gasping motions in pulmonary airway uptake of intra-amniotic iron dextran.

OBJECTIVE: We hypothesized that normal fetal breathing, not acute asphyxial gasping, results in the movement of iron dextran from the amniotic cavity into the fetal lungs. In addition, the amount of iron dextran moving into the fetal lungs is cumulative with time. STUDY DESIGN: Twelve pregnant New Zealand White rabbits at 25 days of gestation were sedated and underwent ultrasound-guided injections of iron dextran into the amniotic cavities of the rabbit fetuses in both horns of each pregnant doe. Oxygen saturation was maintained at >90% in the pregnant does. The 12 does were then equally assigned to four groups on the basis of the duration of fetal exposure to the dextran (0, 8, 16, and 24 hours). At the end of each time point, one half of the fetuses received an intracardiac injection of potassium chloride to induce gasping just before necropsy. Gasping was confirmed by ultrasound scanning. At necropsy, the fetal lungs were evaluated grossly and underwent histomorphometry for iron distribution and quantification in the fetal airways. RESULTS: In the animals that received iron dextran, there was no significant difference in iron accumulation at any time point between those animals that did and did not receive potassium chloride, which suggests that acute gasping does not increase the accumulation of amniotic fluid substances in the lungs. The amount of iron in the fetal airways increased significantly with progressive length of exposure. CONCLUSION: We conclude that normal fetal breathing, not acute asphyxial gasping, resulted in the movement of intra-amniotic iron dextran into the fetal lungs and that the amount of substances that move into the fetal lungs accumulated with time.

Iron dextran: bone imaging patterns of absorption--a case report.

This case illustrates two different patterns of absorption of Iron Dextran in the gluteal soft tissues due to an intramuscular and a more proper Z-track technique. A 65 year old female presented to the nuclear medicine service for a bone scan to rule out metastatic disease from a surgically resected colon cancer. While the first bone scan showed no evidence of metastases, an abnormal accumulation of Technetium-99m methylene diphosphonate was noted in the left gluteal soft tissue region.

Characterization and accumulation of ferritin in hepatocyte nuclei of mice with iron overload.

After a single subcutaneous dose of iron-dextran (600 mg of iron/kg), iron overload developed in C57BL/10ScSn mice. At 4, 24 and 78 wk liver nonheme iron concentrations were 67-, 42- and 21-fold higher than controls, respectively. Much of the iron was in macrophages, but hepatocytes were also strongly positive for Perls' stainable iron. One feature was the development of iron-positive nuclear inclusions in hepatocytes. After a delay of at least 8 wk when no stainable iron was evident, a maximum of 37% of periportal hepatocytes contained inclusions by 24 wk. Although this proportion remained constant for the remainder of the study, the size of the inclusions (which were not membrane-limited) increased to greater than 3 microns in diameter, occupying greater than 25% of the nuclear volume. The presence of iron in the inclusions was confirmed by energy dispersive x-ray microanalysis. Immunocytochemical studies showed that the iron was present as aggregates of ferritin. Quantitation of nonaggregated ferritin molecules by image analyses after electron microscopy demonstrated that within 4 wk ferritin levels in cytoplasm and nucleoplasm had greatly increased but that there was a concentration gradient of approximately one order of magnitude across the nuclear envelope. These findings are consistent with the hypothesis that in iron-loaded mouse hepatocytes there is a slow passage of ferritin-molecules through the nuclear pores; the gradient is maintained by the continual aggregation of ferritin within the nucleus. Intranuclear ferritin may provide a source of iron for catalyzing hydroxyl radical formation in nuclei during some toxic, carcinogenic and aging processes.

Investigation on the dosage/efficacy relationship of iron dextran in veal calves.

The efficacy of a single dose of 800 mg resp. 1600 mg iron in the form of an intramuscularly administrable iron (III)-dextran complex (Anaemex, CAS 9004-66-4) has been tested. On 3 groups of 13 calves each, 0 ml (comparing group), 4 ml resp. 8 ml iron dextran 20% have been applied. All calves received iron-containing food during the test period of 10 weeks. At the beginning of the therapy, 5 weeks and 8 weeks after application, the parameters: weight, hemoglobin, erythrocytes, hematocrit, mean corpuscular hemoglobin (MCH), MCH concentration, mean corpuscular volume, plasma protein, fibrinogen, leukocytes and serum iron were measured. After 10 weeks the dead weight has been determined and the spleen of some calves tested histologically. The study shows that, by the administration of 1600 mg iron as a depot injection, a better growth results with the same quality of veal. The red-coloring of the veal was not significantly different from that of the comparing group. The histological findings show especially that the iron depots of the spleen were empty in all three groups and thereby in this collective no connection exists between the color of the veal and the tested dosage of iron dextran 20%. It is considered meaningful and economic to renounce in future the iron-containing food and in its place to apply intramuscular a single dose of 1600-2400 mg iron per calf. The results are compared with a study on full term infants, which has shown that a intramuscular single dose of 150 mg of iron as iron dextran at birth affords a nutritional advantage in iron status for up to 15 months.(ABSTRACT TRUNCATED AT 250 WORDS)