Pharmacokinetics and tissue distribution of deferoxamine-based nanochelator in rats.

Aim: To characterize the pharmacokinetics of deferoxamine-conjugated nanoparticles (DFO-NPs), a novel nanochelator for removing excess iron. Materials & methods: The pharmacokinetics of DFO-NPs were evaluated in Sprague-Dawley rats at three doses (3.3, 10 and 30 µmol/kg) after intravenous and subcutaneous administration. Results: DFO-NPs exhibited a biphasic concentration-time profile after intravenous administration with a short terminal half-life (2.0-3.2 h), dose-dependent clearance (0.111-0.179 l/h/kg), minimal tissue distribution and exclusive renal excretion with a possible saturable reabsorption mechanism. DFO-NPs after subcutaneous administration exhibited absorption-rate-limited kinetics with a prolonged half-life (5.7-10.1 h) and favorable bioavailability (47-107%). Conclusion: DFO-NPs exhibit nonlinear pharmacokinetics with increasing dose, and subcutaneous administration substantially improves drug exposure, thereby making it a clinically viable administration route for iron chelation.

Iron is an essential metal nutrient, but excess iron produces toxic effects that damage multiple organs including the heart, liver and pancreas. Deferoxamine (DFO) is a US FDA-approved drug for treating iron overload, but its use is limited by serious adverse effects and an inconvenient daily dose scheme. The recent development of a DFO-based nanomedicine (DFO-NP) has shown promise in treating iron overload in animals and was safer in animals. Before this new drug can be given to humans, how it is absorbed into the body, processed in the body and removed from the body when given in different amounts and dose routes must be determined. In this study, we tested the absorption, distribution and removal of DFO-NPs after intravenous and subcutaneous injection in rats. This study showed that DFO-NPs behave differently when changing the dose and that subcutaneous injection makes the drug stay in the body longer without ill effect, which means it could be given to patients this way.

The pharmacokinetic and safety profile of single-dose deferiprone in subjects with sickle cell disease.

Patients with sickle cell disease (SCD) who undergo repeated blood transfusions often develop iron overload. Deferiprone (Ferriprox®) is an oral iron chelator indicated for the treatment of transfusional iron overload due to thalassemia syndromes and has been recently approved as a treatment for iron overload in adult and pediatric patients with SCD and other anemias. The present study aims to characterize the pharmacokinetic (PK) profile of deferiprone (DFP) in adult subjects with SCD. In this phase I, open-label study, subjects with SCD were administered a single 1500 mg dose of DFP. Blood and urine samples were collected for PK assessments of DFP and its main metabolite, deferiprone 3-O-glucuronide (DFP-G). Eight subjects were enrolled and completed the study. Following drug administration, serum levels of DFP and DFP-G rose to maximum concentrations at 1.0 and 2.8 h post-dose, respectively. The half-lives of DFP and DFP-G were 1.5 and 1.6 h, respectively. The majority of administered drug was metabolized and excreted as DFP-G, with less than 4% excreted unchanged in urine up to 10 h post-dose. Subjects received a safety assessment 7 (± 3) days post-dose. Two subjects reported mild adverse events unrelated to the study drug, and no other safety concerns were reported. The PK profile of DFP in SCD subjects is consistent with previous reports in healthy adult volunteers, suggesting no special dosing adjustments are indicated for this population. These findings provide valuable insight for treating iron overload in patients with SCD, who have limited chelation therapy treatment options (trial registration number: NCT01835496, date of registration: April 19, 2013).

Pharmacological and clinical evaluation of deferasirox formulations for treatment tailoring.

Deferasirox (DFX) is the newest among three different chelators available to treat iron overload in iron-loading anaemias, firstly released as Dispersible Tablets (DT) and more recently replaced by Film-Coated Tablets (FCT). In this retrospective observational study, pharmacokinetics, pharmacodynamics, and safety features of DFX treatment were analyzed in 74 patients that took both formulations subsequently under clinical practice conditions. Bioavailability of DFX FCT compared to DT resulted higher than expected [Cmax: 99.5 (FCT) and 69.7 (DT) µMol/L; AUC: 1278 (FCT) and 846 (DT), P < 0.0001]. DFX FCT was also superior in scalability among doses. After one year of treatment for each formulation, no differences were observed between the treatments in the overall iron overload levels; however, DFX FCT but not DT showed a significant dose-response correlation [Spearman r (dose-serum ferritin variation): - 0.54, P < 0.0001]. Despite being administered at different dosages, the long-term safety profile was not different between formulations: a significant increase in renal impairment risk was observed for both treatments and it was reversible under strict monitoring (P < 0.002). Altogether, these data constitute a comprehensive comparison of DFX formulations in thalassaemia and other iron-loading anaemias, confirming the effectiveness and safety characteristics of DFX and its applicability for treatment tailoring.

Effect of Genetic Polymorphisms on the Pharmacokinetics of Deferasirox in Healthy Chinese Subjects and an Artificial Neural Networks Model for Pharmacokinetic Prediction.

BACKGROUND AND OBJECTIVE: Deferasirox is an oral iron chelator used to reduce iron levels in iron-overloaded patients with transfusion-dependent anemia or non-transfusion-dependent thalassemia. This study investigated the effects of genetic polymorphisms on the pharmacokinetics of deferasirox in healthy Chinese subjects and constructed a pharmacokinetic prediction model based on physiologic factors and genetic polymorphism data. METHODS: Twenty-eight subjects were enrolled in a randomized, open-label, two-period crossover study, and they received a single dose of one of two formulations of deferasirox (20 mg/kg) with a 7-day washout interval between the two periods. The plasma defersirox concentration was determined using a validated liquid chromatography-tandem mass spectrometry method, and pharmacokinetic parameters were calculated using the noncompartmental method. The polymorphisms of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1), UGT1A3, multidrug resistance protein 2 (MRP2), cytochrome P450 1A1 (CYP1A1), and breast cancer resistance protein 1 (BCRP1) were genotyped using Sanger sequencing. A back-propagation artificial neural network (BP-ANN) model was used to predict the pharmacokinetics. RESULTS: The UGT1A1 rs887829 C > T single-nucleotide polymorphism (SNP) significantly influenced the area under the plasma concentration-time curve and the terminal half-life. Neither the MRP2 rs2273697 G > A SNP nor BCRP1 rs2231142 G > T SNP altered the absorption, disposition, and excretion of the drug. The BP-ANN model had a high goodness-of-fit index and good coherence between the predicted and measured concentrations (R2 = 0.921). CONCLUSION: Metabolic enzyme-related genetic polymorphisms were more strongly associated with the pharmacokinetics of deferasirox than membrane transporter-related genetic polymorphisms in the Chinese population. TRIAL REGISTRATION: www.Chinadrugtrials.org.cn CTR20191164.

Characterization of two siderophores produced by Bacillus megaterium: A preliminary investigation into their potential as therapeutic agents.

BACKGROUND: Microorganisms produce siderophores in order to scavenge iron from the environment and this study focuses on the characterization of the two siderophores secreted by Bacillus megaterium. The general biological properties and pharmacokinetics following oral application of these compounds are reported. METHODS: Under optimized culture conditions, the siderophores were harvested, purified by chromatography and identified using LC-MS and NMR. Two dihydroxamate siderophores were isolated, schizokinen (MW = 420) and schizokinen imide (MW = 402). RESULTS: Both compounds demonstrate strong antioxidant activity and were found to be relatively nontoxic to both human hepatocellular carcinoma (Huh7) and peripheral blood mononuclear cells. The siderophores possess a strong affinity for iron(III) and decrease the levels of the labile iron pool (LIP) in iron-loaded cells in a concentration-dependent manner. Schizokinen, was detected as both the free siderophore and the iron complex in the plasma and urine of rats after oral gavage. CONCLUSIONS: However, the bioavailability was low and thus schizokinen, like deferoxamine, has no potential as an orally active iron chelator for the treatment of systemic iron overload. GENERAL SIGNIFICANCE: By virtue of the high affinity of schizokinen for tribasic metals, this siderophore does have considerable potential for the chelation of gallium(III) and the development of clinical diagnostic reagents.

Action of iron chelator on intramyocardial hemorrhage and cardiac remodeling following acute myocardial infarction.

Intramyocardial hemorrhage is an independent predictor of adverse outcomes in ST-segment elevation myocardial infarction (STEMI). Iron deposition resulting from ischemia-reperfusion injury (I/R) is pro-inflammatory and has been associated with adverse remodeling. The role of iron chelation in hemorrhagic acute myocardial infarction (AMI) has never been explored. The purpose of this study was to investigate the cardioprotection offered by the iron-chelating agent deferiprone (DFP) in a porcine AMI model by evaluating hemorrhage neutralization and subsequent cardiac remodeling. Two groups of animals underwent a reperfused AMI procedure: control and DFP treated (N = 7 each). A comprehensive MRI examination was performed in healthy state and up to week 4 post-AMI, followed by histological assessment. Infarct size was not significantly different between the two groups; however, the DFP group demonstrated earlier resolution of hemorrhage (by T2* imaging) and edema (by T2 imaging). Additionally, ventricular enlargement and myocardial hypertrophy (wall thickness and mass) were significantly smaller with DFP, suggesting reduced adverse remodeling, compared to control. The histologic results were consistent with the MRI findings. To date, there is no effective targeted therapy for reperfusion hemorrhage. Our proof-of-concept study is the first to identify hemorrhage-derived iron as a therapeutic target in I/R and exploit the cardioprotective properties of an iron-chelating drug candidate in the setting of AMI. Iron chelation could potentially serve as an adjunctive therapy in hemorrhagic AMI.

A new tripodal kojic acid derivative for iron sequestration: Synthesis, protonation, complex formation studies with Fe3+, Al3+, Cu2+ and Zn2+, and in vivo bioassays.

This work presents the simple and low cost synthesis of a new tripodal ligand, in which three units of kojic acid are coupled to a tris(2-aminoethyl)amine (tren) backbone molecule. The protonation equilibria, together with the complex formation equilibria of this ligand with Fe3+, Al3+, Cu2+ and Zn2+ ions were studied. The complementary use of potentiometric, spectrophotometric and NMR techniques, and of Density Functional Theory (DFT) calculations, has allowed a thorough characterization of the different species involved in equilibrium. The stability of the formed complexes with Fe3+ and Al3+ are high enough to consider the new ligand for further studies for its clinical applications as a chelating agent. Biodistribution studies were carried out to assess the capacity the ligand for mobilization of gallium in 67Ga-citrate injected mice. These studies demonstrated that this ligand efficiently chelates the radiometal in our animal model, which suggests that it can be a promising candidate as sequestering agent of iron and other hard trivalent metal ions. Furthermore, the good zinc complexation capacity appears as a stimulating result taking into a potential use of this new ligand in analytical chemistry as well as in agricultural and environmental applications.

A phase I study of the safety and tolerability of VLX600, an Iron Chelator, in patients with refractory advanced solid tumors.

Introduction VLX600 is a novel iron chelator designed to interfere with intracellular iron metabolism, leading to inhibition of mitochondrial respiration and bioenergetic catastrophe and resultant tumor cell death. Methods We conducted a multicenter, phase 1, dose escalation study to determine the safety and adverse event profile and the maximum tolerated dose and recommended phase 2 dose of VLX600. Other endpoints included pharmacokinetics, and preliminary evidence of anti-cancer efficacy as assessed according to RECIST 1.1 criteria. VLX600 was administered intravenously on days 1, 8, and 15 of each 28-day treatment cycle. Results Nineteen patients were enrolled, and seventeen received at least one dose of VLX600. Dose increments were reduced to 50% after dose level 3 (40 mg) due to the occurrence of a grade 3 pulmonary embolism. The study was then closed early due to slow recruitment. No maximum tolerated dose (MTD) nor RP2D had been identified at the time of study closure. Overall, the drug was well tolerated and no DLTs were observed. Fourteen patients experienced drug-related adverse events of any grade. The most frequently reported drug-related AEs were fatigue, nausea, constipation, vomiting, increased alkaline phosphatase, anemia, and decreased appetite. No formal efficacy or survival analyses were performed. No objective responses were observed, though six patients (32%) had stable disease as best response. Conclusion VLX600 was reasonably well tolerated and, together with preclinical data, there is support for further efforts to explore its activity as single agent and in combination with drugs or radiation.

Nanogel-DFO conjugates as a model to investigate pharmacokinetics, biodistribution, and iron chelation in vivo.

Deferoxamine (DFO) to treat iron overload (IO) has been limited by toxicity issues and short circulation times and it would be desirable to prolong circulation to improve non-transferrin bound iron (NTBI) chelation. In addition, DFO is currently unable to efficiently target the large pool of iron in the liver and spleen. Nanogel-Deferoxamine conjugates (NG-DFO) can prove useful as a model to investigate the pharmacokinetic (PK) properties and biodistribution (BD) behavior of iron-chelating macromolecules and their overall effect on serum ferritin levels. NG-DFO reduced the cytotoxicity of DFO and significantly reduced cellular ferritin levels in IO macrophages in vitro. PK/BD studies in normal rats revealed that NG-DFO displayed prolonged circulation and preferential accumulation into the liver and spleen. IO mice treated with NG1-DFO presented significantly lower levels of serum ferritin compared to DFO. Total renal and fecal elimination data point to the need to balance prolonged circulation with controlled degradation to accelerate clearance of iron-chelating macromolecules.

Clinical relevance of deferasirox trough levels in ß-thalassemia patients.

We evaluated the role of deferasirox therapeutic drug monitoring in order to avoid toxicity or treatment failure. Plasma concentrations, measured between two consecutive liver iron determinations, were determined at the end of dosing interval. Fifty-four ß-thalassemic adult patients were enrolled: 50% were males; median age was 32.3 years (IQR 19.1-41.7 years) and median body mass index was 22.25 kg/m2 (IQR 20.24-23.75 kg/m2 ). The mean deferasirox dose was 28.6 ± 6.3 mg/kg/d and mean plasma concentration was 17.3 ± 16.8 µg/mL. Drug levels showed lower results in males. Deferasirox concentration was significantly correlated with serum creatinine levels (P = .01) and serum ferritin (P < .0001). The assessment of deferasirox therapeutic drug monitoring could help clinicians to predict patient responses and to optimize the therapy.

Safety and pharmacokinetics of the oral iron chelator SP-420 in ß-thalassemia.

Our phase I, open-label, multi-center, dose-escalation study evaluated the pharmacokinetics (PK) of SP-420, a tridentate oral iron chelating agent of the desferrithiocin class, in patients with transfusion dependent ß-thalassemia. SP-420 was administered as a single dose of 1.5 (n = 3), 3 (n = 3), 6 (n = 3), 12 (n = 3), and 24 (n = 6) mg/kg or as a twice-daily dose of 9 mg/kg (n = 6) over 14-28 days. There was a near dose-linear increase in the mean plasma SP-420 concentrations and in the mean values for Cmax and AUC0-τ over the dose range evaluated. The median tmax ranged from 0.5 to 2.25 h and was not dose dependent. The study was prematurely terminated by the sponsor due to renal adverse events (AE) including proteinuria, increase in serum creatinine, and one case of Fanconi syndrome. Other adverse effects included hypersensitivity reactions and gastrointestinal disturbances. Based on current dose administration, the renal AE observed outweighed the possible benefits from chelation therapy. However, additional studies assessing efficacy and safety of lower doses or less frequent dosing of SP-420 over longer durations with close monitoring would be necessary to better explain the findings of our study and characterize the safety of the study drug.

Response of soybean plants to the application of synthetic and biodegradable Fe chelates and Fe complexes.

The growing concern over the environmental risk of synthetic chelate application promotes the search for alternatives in Fe fertilization, such as biodegradable chelating agents and natural complexing agents. In this work, plant responses to the application of several Fe treatments (chelates and complexes) was analyzed to study their potential use in Fe fertilization under calcareous conditions. Thus, the root ferric chelate reductase (FCR) activity of soybean (Glycine max cv. Klaxon) plants was determined, and the effectiveness of the Fe chelates and complexes assessed in a pot experiment, by SPAD and fluorescence induction measurements, and the determination of Fe distribution in plant and soil. Additionally, 57Fe Mössbauer spectroscopy was conducted to identify the Fe forms present in the soybean roots. The highest FCR activity was observed for the chelates EDDS/Fe3+ and IDHA/Fe3+; while no activity was observed when using complexes as Fe substrates. In contrast to the FCR data, the pot experiment confirmed that the o,oEDDHA/Fe3+ is the most effective treatment, and the complexes LS/Fe3+ and GA/Fe3+ are able to alleviate Fe chlorosis, also indicated by SPAD data and the maximal quantum efficiency of photosystem II reaction centers as vitality parameters, and the enhanced plant uptake of Fe from natural sources.

Neuroprotection of brain-permeable iron chelator VK-28 against intracerebral hemorrhage in mice.

Iron overload plays a key role in the secondary brain damage that develops after intracerebral hemorrhage (ICH). The significant increase in iron deposition is associated with the generation of reactive oxygen species (ROS), which leads to oxidative brain damage. In this study, we examined the protective effects of VK-28, a brain-permeable iron chelator, against hemoglobin toxicity in an ex vivo organotypic hippocampal slice culture (OHSC) model and in middle-aged mice subjected to an in vivo, collagenase-induced ICH model. We found that the effects of VK-28 were similar to those of deferoxamine (DFX), a well-studied iron chelator. Both decreased cell death and ROS production in OHSCs and in vivo, decreased iron-deposition and microglial activation around hematoma in vivo, and improved neurologic function. Moreover, compared with DFX, VK-28 polarized microglia to an M2-like phenotype, reduced brain water content, deceased white matter injury, improved neurobehavioral performance, and reduced overall death rate after ICH. The protection of VK-28 was confirmed in a blood-injection ICH model and in aged-male and young female mice. Our findings indicate that VK-28 is protective against iron toxicity after ICH and that, at the dosage tested, it has better efficacy and less toxicity than DFX does.

Deferasirox pharmacogenetic influence on pharmacokinetic, efficacy and toxicity in a cohort of pediatric patients.

AIM: We aimed to evaluate the influence of genetic polymorphisms involved in deferasirox metabolism and transport on its pharmacokinetics and treatment toxicity, in a cohort of ß-thalassaemic children. PATIENTS & METHODS: Drug plasma concentrations were measured by a HPLC-UV method. Allelic discrimination for UGT1A1, UGT1A3, CYP1A1, CYP1A2, CYP2D6, MRP2 and BCRP1 polymorphisms was performed by real-time PCR. RESULTS: CYP1A1 rs2606345AA influenced Ctrough (p = 0.001) and t1/2 (p = 0.042), CYP1A1 rs4646903TC/CC (p = 0.005) and BCRP1 rs2231142GA/AA (p = 0.005) influenced Tmax and CYP2D6 rs1135840CG/GG influenced Cmax (p = 0.044). UGT1A1 rs887829TT (p = 0.002) and CYP1A2 rs762551CC (p = 0.019) resulted as predictive factor of ferritin levels and CYP1A1 rs2606345CA/AA (p = 0.021) and CYP1A2 rs762551AC/CC (p = 0.027) of liver iron concentration. CONCLUSION: Our data suggest the usefulness of deferasirox pharmacogenetics in pediatric treatment optimization.

Deferasirox-Iron Complex Formation Ratio as an Indicator of Long-term Chelation Efficacy in ß-Thalassemia Major.

BACKGROUND: ß-Thalassemia major patients with higher total drug levels [deferasirox (DEFR) plus its iron complex] do not yield better serum ferritin (SF) control. This study aimed to determine the concentrations of DEFR and its iron complex (Fe-[DEFR]2) in thalassemia patients to predict the chelation efficacy in terms of SF and cardiac T2* values. METHODS: Patients' steady-state drug levels at trough (Ctrough) and 2 hours postdose (C2h) were determined. Because iron deposition may cause changes in the hepatic metabolism of amino acids, the concentrations of 40 amino acids in plasma were also assayed at 2 hours postdose. RESULTS: A total of 28 patients either dosing daily or twice daily were recruited. After a 1-month DEFR maintenance therapy, 38.8% and 30% of patients from groups of once-daily and twice-daily, respectively, had a plasma DEFR-iron complex formation ratio higher than 0.05 [High Chelation Ratio, (HCR)]. After a 6-month follow-up, those patients who had a HCR (n = 10) at C2h showed more favorable median changes in SF and cardiac T2* values (-388.0, +10.1) than those with a low DEFR-iron complex formation ratio (Low Chelation Ratio; n = 18; +10.5; +4.5) compared with the baseline. The levels of plasma L-arginine, L-alanine, L-glycine, L-norleucine, and L-serine were significantly lower in patients with the low Chelation Ratio condition than the levels in HCR patients. CONCLUSIONS: This therapeutic drug monitoring study revealed that a DEFR-iron complex formation ratio at C2h might be an applicable indicator of the efficacy of long-term DEFR iron chelation therapy. A better iron-control response to DEFR was observed in the patients with HCRs. The trends for the ratio might have value in dose-setting and need to be validated in a larger cohort.

Iron Chelation Nanoparticles with Delayed Saturation as an Effective Therapy for Parkinson Disease.

Iron accumulation in substantia nigra pars compacta (SNpc) has been proved to be a prominent pathophysiological feature of Parkinson's diseases (PD), which can induce the death of dopaminergic (DA) neurons, up-regulation of reactive oxygen species (ROS), and further loss of motor control. In recent years, iron chelation therapy has been demonstrated to be an effective treatment for PD, which has shown significant improvements in clinical trials. However, the current iron chelators are suboptimal due to their short circulation time, side effects, and lack of proper protection from chelation with ions in blood circulation. In this work, we designed and constructed iron chelation therapeutic nanoparticles protected by a zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) to delay the saturation of iron chelators in blood circulation and prolong the in vivo lifetime, with HIV-1 trans-activating transcriptor (TAT) served as a shuttle to enhance the blood-brain barrier (BBB) permeability. We explored and investigated whether the Parkinsonian neurodegeneration and the corresponding symptoms in behaviors and physiologies could be prevented or reversed both in vitro and in vivo. The results demonstrated that iron chelator loaded therapeutic nanoparticles could reverse functional deficits in Parkinsonian mice not only physiologically but also behaviorally. On the contrary, both untreated PD mice and non-TAT anchored nanoparticle treated PD mice showed similar loss in DA neurons and difficulties in behaviors. Therefore, with protection of zwitterionic polymer and prolonged in vivo lifetime, iron chelator loaded nanoparticles with delayed saturation provide a PD phenotype reversion therapy and significantly improve the living quality of the Parkinsonian mice.

Population pharmacokinetics and dosing recommendations for the use of deferiprone in children younger than 6 years.

AIMS: Despite long clinical experience with deferiprone, there is limited information on its pharmacokinetics in children aged <6 years. Here we assess the impact of developmental growth on the pharmacokinetics of deferiprone in this population using a population approach. Based on pharmacokinetic bridging concepts, we also evaluate whether the recommended doses yield appropriate systemic exposure in this group of patients. METHODS: Data from a study in which 18 paediatric patients were enrolled were available for the purposes of this analysis. Patients were randomised to three deferiprone dose levels (8.3, 16.7 and 33.3 mg kg-1 ). Blood samples were collected according to an optimised sampling scheme in which each patient contributed to a maximum of five samples. A population pharmacokinetic model was developed using NONMEM v.7.2. Model selection criteria were based on graphical and statistical summaries. RESULTS: A one-compartment model with first-order absorption and first-order elimination best described the pharmacokinetics of deferiprone. Drug disposition parameters were affected by body weight, with both clearance and volume increasing allometrically with size. Simulation scenarios show that comparable systemic exposure (AUC) is achieved in children and adults after similar dose levels in mg kg-1 , with median (5-95th quantiles) AUC values, respectively, of 340.6 (223.2-520.0) µmol l-1  h and 318.5 (200.4-499.0) µmol l-1  h at 75 mg kg-1 day-1 , and 453.7 (297.3-693.0) µmol l-1  h and 424.2 (266.9-664.0) µmol l-1  h at 100 mg kg-1  day-1 given as three times daily (t.i.d.) doses. CONCLUSIONS: Based on the current findings, a dosing regimen of 25 mg kg-1  t.i.d. is recommended in children aged <6 years, with the possibility of titration up to 33.3 mg kg-1  t.i.d.

Modulation of iron transport, metabolism and reactive oxygen status by quercetin-iron complexes in vitro.

SCOPE: Excess free-iron is detrimental to health through its ability to participate in free radical generation and amplification of oncogenic pathways. The study aims were to identify polyphenols with iron-chelating potential. METHODS AND RESULTS: Of four polyphenols tested quercetin demonstrated potent iron binding with the physiological outcome dictated by the location of interaction. In the presence of extracellular iron and quercetin, ferritin expression and cellular iron concentrations decreased suggesting the resulting quercetin-iron complex is not internalised. However, in the relative absence of extracellular iron, quercetin becomes internalised and complexes with both intracellular iron, and iron which subsequently becomes absorbed as indicated by increased cellular 59 Fe post pre-culture with quercetin. This increased intracellular iron complexed to quercetin does not associate with the labile iron pool and cells behave as though they are iron deficient (increased transferrin receptor-1 and iron regulatory protein-2 expression and low ferritin expression). Additionally, a suppression in reactive oxygen species was observed. CONCLUSION: Quercetin, an exogenous iron chelator, is able to render the cell functionally iron-deficient which not only provides a therapeutic platform for chelating excess free luminal iron but also may be of use in limiting processes such as cancer-cell growth, inflammation and bacterial infections, which all require iron.

Deferasirox pharmacokinetic evaluation in ß-thalassaemia paediatric patients.

OBJECTIVES: Iron chelation in the transfusion-dependent anaemias management is essential to prevent end-organ damage and to improve survival. Deferasirox is a once-daily orally active tridentate selective iron chelator which pharmacokinetic disposition could influence treatment efficacy and toxicity. Therapeutic drug monitoring is an important tool for optimizing drug utilization and doses. METHODS: A fully validated chromatographic method was used to quantify deferasirox concentration in plasma collected from paediatric patients with ß-thalassaemia. Samples obtained after 5 days of washout or in naïve patients before and after 2, 4, 6 and 24 h drug administration were evaluated. KEY FINDINGS: Associations between variables were tested using the Pearson test. Twenty paediatric patients were enrolled; they were mainly men (13.65%), with median age of 6.35 years and body mass index of 15.45 kg/m2 . Concerning pharmacokinetic parameters, a higher interindividual variability was shown. A positive, but not significant, correlation (r = 0.363; P = 0.115) was found between deferasirox area under the concentration curve over 24 h (AUC) and drug dose. CONCLUSIONS: Monitoring plasma deferasirox concentrations appears beneficial for guiding appropriate patient treatment, enhancing effectiveness and minimizing toxicity.