Iron complex compounds for subcutaneous use in the treatment of iron deficiency in companion animals

Abstract

The present invention relates to iron complex compounds for subcutaneous use in methods for treating iron deficiency, particularly iron deficiency anemia, for example in companion animals, and pharmaceutical compositions for subcutaneous administration comprising an iron complex compound and a pharma- ceutical acceptable carrier.The present invention more particularly, but not exclusively, relates to iron octasaccharide complexes, pharmaceutical compositions comprising the iron octasaccharide complexes, and iron octasaccharide complexes for use in methods for treating iron deficiency, particularly iron deficiency anemia, in human or non-human subjects.

Description

[Technical field]

[0001] The present invention relates to an iron complex compound for subcutaneous use in a method for treating iron deficiency in a companion animal, and to a pharmaceutical composition for subcutaneous administration comprising an iron complex compound and a pharma- ceutical acceptable carrier.The present invention more particularly, but not exclusively, relates to an iron octasaccharide complex, a pharmaceutical composition comprising an iron octasaccharide complex, and an iron octasaccharide complex for use in a method for treating iron deficiency in a human or non-human subject. [Background technology]

[0002] Anemia is a relatively common clinical sign and laboratory abnormality in dogs and other companion animals. Of all dogs admitted to clinical practice at the US Banfield Hospital in 2005, between 3% and 11% were anemic (Lund, 2007). Of these anemic dogs, a certain percentage is believed to be anemic due to iron deficiency (ID), and it has been estimated that 20-110 dogs per 10,000 suffer from canine iron deficiency anemia (IDA). With a dog population of approximately 90 million in the US (American Pet Products Association, National Pet Owners Survey 2016), this translates to 180,000-990,000 dogs suffering from IDA. Thus, IDA in dogs is as prevalent and important as it is in humans.

[0003] The field of clinical hematology is key to most diseases in companion animals, including anemia caused by blood loss, hemolysis, bone marrow disease, bleeding disorders, hematopoietic toxicity, infection, and cancer. It addresses the routine and specific diagnostics of red blood cells (RBCs), white blood cells, platelets, and clotting factors, and the supportive and specific treatment of anemia, including transfusion therapy.

[0004] During erythropoiesis, RBCs are generated from pluripotent stem cells in the bone marrow and grow and mature over 7-10 days before mature RBCs are released into the circulation. Erythropoiesis is primarily regulated by the renal hormone erythropoietin, which is synthesized and released from renal cells during renal hypoxia. Hemoglobin is synthesized during the later stages of erythrocyte maturation from burst-forming units and (meta)erythrocytes to reticulocytes. Iron must be present in the bone marrow for hemoglobinization to occur.

[0005] For example, in healthy dogs, red blood cells make up 36–58% of blood volume. Because they lack nuclei and mitochondria, they have a finite life span of about 100 days and are destroyed by macrophages outside blood vessels. The primary function of RBCs is to act as oxygen carriers. Each RBC contains about 33% hemoglobin (Hb), which is composed of four globin chains and one central heme containing iron. Iron in the ferrous (Fe2+) form can bind oxygen and either bind oxygen to hemoglobin (lungs) or release oxygen from Hb (peripheral tissues) depending on the oxygen partial pressure. Tissue oxygenation is essential for energy production and all cellular functions.

[0006] The term anemia is derived from the Greek words "an" (without) and "heima" (blood). Anemia is a clinical sign in animals or a clinical condition in humans. Low Hb concentration and / or low hematocrit (Hct) / packed cell volume (PCV) indicate the presence of anemia. Hb concentration is preferred in human medicine, while Hct / PCV is most commonly used in veterinary medicine (although these parameters are less accurate). Mechanistically, anemia is classified as hemolytic anemia, blood loss anemia, and reduced or inefficient erythropoiesis. In hemolysis, the Hb breakdown products of lysed RBCs are recycled, generally making large amounts of iron available. Blood loss can be internal or external and can be localized due to lacerations or multifocal due to impaired hemostasis; chronic external bleeding results in iron IDA. Additionally, reduced or inefficient erythropoiesis can have many causes, including toxicity, infection, cancer, kidney disease, and nutritional deficiencies such as iron and vitamin B12 deficiency (Giger, 2005; Weiss, 2010).

[0007] For example, dogs have about 10-50 mg iron / kg body weight, most of which is present as Hb in red blood cells; in fact, every 2 mL of blood contains 1 mg of iron. In addition, myoglobin in muscle tissue and many important enzymes in all cells, such as the cytochromes involved in energy and drug metabolism, represent heme proteins and contain iron. Iron is transported via transferrin in the blood and is stored as a soluble mobile fraction (ferritin) and an insoluble fraction (hemosiderin) mainly in the spleen, liver and bone marrow, depending on the amount of iron present (Olver et al., 2010; Cohen-Solal et al., 2014). Transferrin represents the iron transporter in plasma and is usually 20-60% saturated.

[0008] Under physiological conditions, iron losses from the intestine, urine, and skin are negligible, amounting to less than 1–2 mg / day in dogs. Iron is ingested through the diet, and canine diets, including meat, are rich in iron. Too much iron can be toxic, so iron balance is carefully regulated by absorption from the intestine. The mechanism of iron absorption in the duodenum has been elucidated recently, with the hepatic hormone hepcidin being the main inhibitory regulator. Iron absorption increases with decreasing iron stores and increasing erythropoietic activity, and is associated with decreased hepcidin concentrations. In the presence of high serum iron concentrations, hepcidin is released from the liver and complexes with ferroportin, decreasing intestinal iron absorption (Olver et al., 2010).

[0009] Companion animals with IDA, such as dogs, are commonly managed with blood transfusions, parenteral and oral iron supplements in addition to correcting the cause of IDA, but there are no detailed reports on the efficacy and safety of treatments in canine medicine. The timely development and regulatory approval of a safe and effective parenteral iron preparation would be of great benefit and value to dogs and other companion animals with IDA.

[0010] As far as oral iron preparations and iron food supplements are concerned, it can be summarized (although there is little hard evidence) that ferrous sulfate, gluconate, or fumarate can be effective at doses of 5 mg / lb per day or 100 to 300 mg per day, provided that a) gastrointestinal iron uptake is normal, b) gastrointestinal side effects (such as vomiting and diarrhea) are absent or tolerable, and c) the daily dosage is adhered to for several weeks to months.

[0011] Regarding parenteral iron, there are currently no such agents approved in the United States or many other countries for the prevention, treatment, management, or control of IDA in dogs. Despite this situation, several sources describe the use of iron dextran products approved for humans or piglets in dogs. Various recommendations reflect this situation: Plumb's Veterinary Drug Handbook (Plumb, 2008): "For iron deficiency anemia, administer a single dose of ferric dextran at 10-20 mg / kg, followed by oral therapy with ferrous sulfate." Textbook of Veterinary Internal Medicine (Giger, 2005): "To replenish iron stores in iron deficiency anemia secondary to disease, when oral iron supplementation is deemed inappropriate or insufficient, or when gastrointestinal disorders prevent iron absorption, parenteral iron may be administered: up to 2 mL daily of iron dextran complex (50 mg / mL) intramuscularly." This translates to a maximum of 100 mg of iron daily, or a maximum of 20 mg / kg for a 5 kg / 11 lb dog, with lower specific doses (mg / kg / day) for larger dogs. Small Animal Internal Medicine (Nelson and Couto, 1998): In iron deficiency anemia, "intramuscular iron dextran may also be administered at a dose of 10 mg / kg once to twice weekly. This form of iron therapy is associated with pain at the injection site and the potential for anaphylactic reactions." · Blackwell's Five-Minute Veterinary Consult (Weiser, 2015): For iron deficiency anemia, "Initiate iron therapy with iron injections. Iron dextran - an injectable slow-release form of iron; one injection (10-20 mg / kg IM) followed by oral supplements."

[0012] Although Belfer® (dextran iron complex 100 mg / mL, bela-pharm GmbH & Co. KG) is approved for use in a variety of animal species, the safety and efficacy of Belfer® has not been studied in all approved species - in particular, it appears not to have been studied in cats and dogs to date. Nevertheless, it is approved for use in dogs in several countries. The approved dosage and administration for dogs is 1-2 mg iron per kg body weight (i.e., 0.01-0.02 mL per kg body weight) administered as an intramuscular injection. This is a fairly low and likely subtherapeutic dose for the treatment of canine IDA.

[0013] A safe parenteral iron preparation for dogs with IDA, administered in an appropriate dose and by an appropriate method, would have the important advantage of a very rapid onset of therapeutic effect in replenishing iron stores and increasing Hb concentrations and therefore Hct / PCV.

[0014] There have been several published case reports of dogs receiving intramuscular injections of iron dextran at doses of 10 to 20 mg / kg for the treatment or management of IDA. Examples of such case reports include: A single injection of 13 mg / kg iron dextran in golden retrievers (Cook and Kvitko-White, 2014). A single injection of 15mg / kg iron dextran in a mongrel dog (Thrall and Gillespie, 2011). Three injections of 10 mg / kg iron dextran within one week in two dogs (Harvey et al., 1982). One or two injections of 20 mg / kg iron dextran given 6 to 13 days apart in seven dogs (Fry and Kirk, 2006).

[0015] Another report described the infusion of iron oligosaccharides into healthy dogs: injection of iron(III) hydroxide oligosaccharides at doses of 7.1 mg / kg and 21.3 mg / kg (Preusser et al., 2005).

[0016] However, there are currently no parenteral iron preparations developed specifically for the treatment of iron deficiency in companion animals.

[0017] The present invention has been devised in view of the above considerations. Summary of the Invention

[0018] In one aspect, the present invention relates to an iron complex compound for subcutaneous use in a method for the treatment of iron deficiency in a companion animal. In a first embodiment of the first aspect, the companion animal is a dog. In a second embodiment of the first aspect, the method comprises administering a dose of 20 mg elemental iron per kg body weight.

[0019] In a second aspect, the present invention relates to a pharmaceutical composition for subcutaneous administration comprising an iron complex compound and a pharma- ceutically acceptable carrier. In a first embodiment of said second aspect, the pharmaceutical composition is a ready-to-use injectable composition. In a second embodiment of the second aspect, the pharmaceutical composition comprises 100 mg / mL elemental iron.

[0020] In a further embodiment of the first and second aspects, the iron complex compound is an iron oligoisomaltose complex or an iron oligoisomaltoside complex. In a particular embodiment, the iron complex compound is an iron oligosaccharide complex comprising iron complexed with an oligoisomaltoside, wherein (i) the oligoisomaltoside has a weight average molecular weight in the range of 850 to 1150 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the oligoisomaltoside; (iii) the fraction having more than 9 monosaccharide units is less than 30% by weight of the oligoisomaltoside; (iv) at least 40% by weight of the molecules have 3 to 6 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the complex is in the range of 130,000 to 180,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is less than or equal to 2.5% by weight of the oligoisomaltoside. Alternatively, and preferably, in consideration of the context of subcutaneous administration, the iron complex compound is an iron octasaccharide complex comprising iron complexed with an octasaccharide, wherein (i) the octasaccharide has a weight average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6 to 10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the polydispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is 2.5% by weight or less of the octasaccharide.

[0021] In a third aspect, the present invention relates to said iron octasaccharide, a pharmaceutical composition comprising said iron octasaccharide and a pharma- ceutically acceptable carrier, and an iron octasaccharide complex, for use in a method of treatment, more particularly for use in a method of treatment of iron deficiency, such as iron deficiency anemia, in a human or non-human subject.

[0022] The present invention includes any combination of the described aspects and preferred features unless the combination is expressly not permitted or explicitly avoided. [Brief description of the drawings]

[0023] BRIEF DESCRIPTION OF THE DRAWINGS Embodiments and experiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings in which: FIG. [Figure 1] FIG. 1 shows baseline-corrected serum iron concentrations (μmol / L; mean + / - SD) following administration of an intramuscular (IM) dose (20 mg / kg=T4) or subcutaneous (SC) dose (20 mg / kg=T1; 60 mg / kg=T2; and 100 mg / kg=T3) of iron oligoisomaltoside complex. [Diagram 2] FIG. 2 shows the change from baseline ferritin (ng / mL; mean + / - SD) following administration of an IM dose (20 mg / kg=T4) or SC dose (20 mg / kg=T1; 60 mg / kg=T2; and 100 mg / kg=T3) of iron oligoisomaltoside complex. Detailed Description of the Invention

[0024] Aspects and embodiments of the present invention are discussed below with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are hereby incorporated by reference.

[0025] [Definition] In order that this description may be more readily understood, certain terms are first defined. Additional definitions are set forth throughout the detailed description.

[0026] "Treatment" refers to any type of intervention or process performed on a subject, or administration of an active agent to a subject, with the purpose of reversing, mitigating, ameliorating, inhibiting, slowing the progression, development, severity, or recurrence of clinical signs or symptoms, complications, conditions, or biochemical manifestations associated with a disease or disorder, or preventing its onset. As used herein, "treatment" particularly includes the prevention, control, treatment, or management of a disease or disorder, such as iron deficiency or iron deficiency anemia. According to the present invention, the treatment or management of ID, particularly IDA, represents a particular embodiment.

[0027] A "subject" includes any human or non-human animal. The term "non-human animal" includes, but is not limited to, vertebrates such as non-human primates, companion animals, particularly canines, felines, equines, and camelids, and rodents such as mice, rats, and guinea pigs. The term "non-human animal" also includes livestock such as pigs, goats, sheep, and cows. The terms "subject" and "patient" are used interchangeably herein.

[0028] The term "companion animal" refers to an animal suitable for human companionship. In some embodiments, a companion animal is a canine (such as a dog), feline (such as a cat), equine (such as a horse), or camel. In some embodiments, a companion animal species is a small mammal such as a dog, cat, rabbit, ferret, guinea pig, rodent, and the like. In some embodiments, a companion animal species is a domestic animal such as a horse or a llama. In some embodiments, a companion animal species is an animal used in racing, e.g., a racing animal such as a racing dog or a racing horse. Companion animals should be distinguished from domestic animals such as pigs, goats, sheep, cows, and the like.

[0029] A "therapeutically effective amount" or "therapeutically effective dose" of a drug or therapeutic agent is any amount of drug that, when used alone or in combination with another therapeutic agent, protects a subject from developing a disease or promotes disease regression as evidenced by a decrease in the severity of disease symptoms, an increase in the frequency and duration of disease symptom-free periods, or prevention of functional impairment and disability due to disease affliction. The ability of a therapeutic agent to promote disease regression can be assessed using a variety of methods known to those of skill in the art, such as in human or animal subjects during clinical trials, in animal model systems predictive of efficacy in humans, or by assaying for drug activity in in vitro assays.

[0030] The terms "pharmaceutical formulation" and "pharmaceutical composition" refer to a preparation that is in a form that allows the biological activity of the active ingredient to be effective and that does not contain additional ingredients that are unacceptably toxic to the subject to which the formulation is administered.

[0031] "Pharmaceutically acceptable carrier" refers to a non-toxic solid, semi-solid, or liquid filler, diluent, encapsulating material, formulation auxiliary, or carrier common in the art for use with therapeutic agents, which together constitute a "pharmaceutical composition" for administration to a subject. Pharmaceutically acceptable carriers are non-toxic to recipients at the dosages and concentrations employed and are compatible with other ingredients of the formulation. Pharmaceutically acceptable carriers are appropriate for the formulation being used.

[0032] For the purposes of this document, when a dosage of an iron complex compound is specified in mg or g, as is customary in the literature, the value refers to the amount of elemental iron provided in mg or g.

[0033] [Treatment method] Described herein is a method of treatment, i.e., treatment of iron deficiency, comprising administering an iron complex compound according to a defined dosing regimen and / or to a particular subject. The invention therefore also relates to iron complex compounds for use in said method, to the use of iron complex compounds for the treatment of iron deficiency, and / or to the use of iron complex compounds in the manufacture of a medicament for the treatment of iron deficiency.

[0034] The method of the present invention is typically performed on a subject in need thereof. The subject in need of the method of the present invention is a subject suffering from, diagnosed with, suspected of, or at risk of developing iron deficiency (ID). In some embodiments, the iron deficiency is iron deficiency anemia. Iron deficiency anemia (IDA) develops when iron stores are depleted. A subject suffering from ID may suffer from IDA; a subject suffering from IDA necessarily suffers from ID. Methods for diagnosing ID and IDA are well established in the art and are commonly used in clinical settings.

[0035] For subjects suffering from, diagnosed with, suspected of, or at risk of developing ID or IDA, parenteral iron in the form of iron complex compounds is administered when oral iron is not tolerated or effective or cannot be used, for example, in subjects who (i) are intolerant to oral iron, or (ii) have an unsatisfactory response to oral iron, or (iii) have not actually completed the use of oral iron for the required period (i.e., are non-adherent / non-compliant to the oral iron treatment course). Another situation in which intravenous, subcutaneous, or intramuscular iron is required is when iron needs to be delivered rapidly, i.e., when there is a clinical need to rapidly replenish iron stores.

[0036] [Target of treatment: companion animals] The present invention is particularly directed to the treatment of iron deficiency in companion animals such as canines (such as dogs), felines (such as cats), or equines (such as horses), particularly canines and felines such as dogs and cats. Preferably, the companion animal according to the present invention is a dog.

[0037] The present invention also relates to the treatment of iron deficiency in a human or non-human subject.

[0038] [Iron deficiency and anemia] Iron deficiency anemia occurs when iron is unavailable during erythropoiesis, either because body iron stores are insufficient or depleted (absolute IDA) or because iron cannot be mobilized from other sufficient body iron stores (functional IDA).

[0039] Functional iron deficiency anemia is observed with infections, inflammation and cancer (Naigamwalla et al., 2012), where hepcidin sequesters iron as an insoluble form of hemosiderin in macrophages of the liver, spleen and bone marrow, and therefore iron cannot be mobilized for erythropoiesis (Dignass, 2015), leading to functional IDA.

[0040] In obligate IDA, body iron stores are depleted over a period of weeks, either as a result of chronic blood loss or reduced dietary iron intake. Chronic external blood loss is the primary cause of iron deficiency anemia in dogs. Severe infestations with external infestations such as fleas and, less commonly, tick and maggot infestations, and internal infestations such as hookworms and, less commonly, whipworms, can cause significant blood loss. Iron loss can also occur due to bleeding GI tumors such as leiomyomas / sarcomas and lymphomas, as well as ulcerogenic drugs (glucocorticosteroids, nonsteroidal anti-inflammatory drugs, chemotherapy drugs), as chronic and intermittent gastrointestinal (GI) blood loss is a frequent cause of chronic or recurrent external bleeding. In addition, chronic inflammatory bowel disease (IBD) can be associated with significant blood loss. Excessive donations from small subjects and frequent phlebotomy for diagnostic purposes may also lead to iron deficiency, since routine collection of approximately 450 ml of blood from a donor weighing over 23 kg removes approximately 200 mg of iron from the body.

[0041] While the above triggers may cause massive bleeding despite normal hemostasis, hemostatic disorders may further cause chronic and / or recurrent severe bleeding followed by IDA. These include inherited coagulation disorders, thrombocytopenia, thrombocytopathy, and von Willebrand's disease.

[0042] In neonatal and juvenile subjects, such as puppies and young dogs, the iron required for rapid growth and erythropoiesis may exceed the available supply from diet and internal stores. Indeed, neonatal iron stores are generally low, and maternal milk is also low in iron. Nevertheless, IDA is typically only seen in puppies with chronic external blood loss from internal and external parasites.

[0043] Thus, conditions that cause iron deficiency anemia (IDA) include, but are not limited to, bleeding into the gastrointestinal (GI) tract that may be due to internal parasites (e.g., hookworms and whipworms), gastrointestinal neoplasms (e.g., leiomyomas / sarcomas), gastric ulcers (e.g., induced by drugs such as glucocorticoids, nonsteroidal anti-inflammatory drugs, or chemotherapy agents), inflammatory bowel disease (IBD), or other severe GI infiltration, including cancer; other external bleeding, such as nosebleeds (nasal tumors, foreign bodies, infections), hemorrhagic cystitis; kidney / bladder neoplasms, blood donations (especially if frequently repeated) These include conditions such as: external parasites (e.g. fleas, ticks, maggots), bleeding from skin lesions, surgery / trauma, or uterine and vaginal blood loss; hemostatic disorders such as coagulation disorders, thrombocytopenia, thrombocytopathia, von Willebrand disease, or vascular disorders; dietary iron deficiency, for example in nursing puppies or weaned puppies, due to an iron deficient diet (not including meat) or defective iron absorption (e.g. iron-resistant iron deficiency anemia); and other conditions such as chronic kidney disease (CKD).

[0044] Conditions that cause IDA can be chronic or non-chronic. Conditions of chronic or ongoing blood loss that can cause IDA may result from etiologies that are difficult to address and treat. Examples are cancer, gastrointestinal (GI) bleeding (e.g., induced by unresectable tumors), or inflammatory conditions such as inflammatory bowel disease (IBD). Such conditions may be manageable or controllable only in the sense that their effects can be delayed or reduced by using a treatment that manages or controls the disease or condition. Such diseases or conditions may be described as chronic, ongoing, intermittent, and / or untreatable. In certain embodiments, IDA caused by a chronic disease or condition is managed or controlled by administering more than one dose of an iron complex compound to a subject (e.g., by repeated administration).

[0045] IDA may also be caused by one or more underlying treatable, non-chronic diseases or conditions, such as ectoparasites (e.g., fleas, ticks, maggots) and endoparasites (e.g., hookworms and whipworms), gastrointestinal (GI) bleeding (e.g., induced by resectable tumors and neoplasms, ulcers, lacerations, nonsteroidal anti-inflammatory drug-induced bleeding), malabsorption of dietary iron, inadequate nutrition, or other external bleeding (e.g., urinary bleeding, cystitis, trauma, surgical blood loss, blood donation). Such conditions may be treated. Such diseases or conditions may be described as acute, non-chronic, and / or treatable. In certain embodiments, IDA caused by a non-chronic disease or condition is treated by administering a single dose of an iron complex compound to the subject.

[0046] The frequency with which the above conditions occur in companion animals varies with species. For example, in cats, CKD can occur at any age, but is most commonly seen in middle-aged to older cats (age 7 and above), with increasing frequency with age. Thus, cats with CKD represent a particular subject group amenable to treatment according to the present invention. Other particular subject groups amenable to treatment according to the present invention will be apparent to those skilled in the art of veterinary medicine.

[0047] [Clinical signs and symptoms of iron deficiency and iron deficiency anemia] Diagnosis of iron deficiency and iron deficiency anemia is based on evaluation of a subject's medical history and presenting clinical signs or symptoms (physical exam) in combination with hematological analysis.

[0048] Symptoms of iron deficiency in humans may appear before the condition progresses to iron deficiency anemia. Symptoms of iron deficiency may include, for example, fatigue, dizziness, paleness, hair loss, irritability, weakness, pica, brittle or grooved nails, Plummer-Vinson syndrome (painful atrophy of the mucous membranes lining the tongue, pharynx, and esophagus), immune dysfunction, dysphagia, and restless legs syndrome, among others.

[0049] In companion animals such as dogs, iron deficiency and iron deficiency anemia develop over weeks to months and are often insidious, allowing the animal to adapt significantly. Except for certain signs of external bleeding involving the intestinal tract, clinical signs are rather nonspecific and depend on the rate of progression rather than the degree of anemia. Common clinical signs in ID or IDA animals include, but are not limited to, facial pallor, exercise intolerance, lethargy, jumping pulse, gallop rhythm, systolic flow murmur, pica, cardiac hypertrophy, nail changes, and decreased muscle activity. A history of blood loss, external / internal parasitosis, GI disease such as GI ulcers, neoplasms, renal disease, or other possible associated causes of ID and IDA are helpful indicators.

[0050] A subject undergoing treatment with the methods disclosed herein may experience improvement in iron deficiency (ID). A subject undergoing treatment with the methods disclosed herein may experience improvement in iron deficiency anemia (IDA). This improvement may occur as the total amount of iron in the subject's body, blood hemoglobin concentration, and / or blood's oxygen-carrying capacity increases through administration of the iron complex compounds disclosed herein. In some embodiments, a subject undergoing treatment with the methods disclosed herein experiences a reduction in one or more clinical signs or one or more symptoms of ID or IDA. In some embodiments, the reduction is temporary. In preferred embodiments, the temporary reduction in one or more clinical signs or one or more symptoms of ID or IDA allows the subject to receive additional doses of the iron complex compound. In other embodiments, the reduction is permanent. In some embodiments, a subject undergoing treatment with the methods disclosed herein experiences elimination of one or more clinical signs or symptoms of ID or IDA. In some embodiments, one or more clinical signs or symptoms of ID or IDA are selected from facial pallor, exercise intolerance, lethargy, borderline pulse, gallop rhythm, systolic flow murmur, pica, cardiac hypertrophy, nail changes, and decreased muscle activity, and combinations of the former.

[0051] [Iron storage parameters] Subjects suffering from iron deficiency may be evidenced by low or inadequate markers of total body iron status. This means that such subjects may not have enough iron stored in their body to maintain adequate iron levels. For example, most healthy, well-fed dogs may have several grams of iron stored in their body. Some of this iron is contained in hemoglobin, which carries oxygen through the blood. Most of the remaining iron is contained in iron-binding complexes present in all cells, but is more highly concentrated in bone marrow and organs such as the liver and spleen. Liver iron stores are the main physiological iron store in a healthy body. A portion of the body's total iron content is available in proteins that use iron for cellular processes such as oxygen storage (myoglobin) or carrying out energy-generating redox reactions (cytochrome proteins). In addition to stored iron, a small amount of iron circulates in the plasma bound to a protein called transferrin.

[0052] Subjects with iron deficiency first exhaust their body's iron stores. Iron deficiency anemia is the primary clinical sign of iron deficiency, since most of the iron available to the body is required for hemoglobin. Oxygen transport to tissues, including organs, is essential, and severe anemia can be harmful and potentially fatal due to total body oxygen deficiency. Subjects with iron deficiency can suffer organ damage caused by oxygen deficiency and even die long before cells are depleted of the iron required for intracellular processes.

[0053] There are several markers of whole body iron status that can be measured to determine whether a subject has sufficient iron stores to maintain adequate health. These markers can be circulating iron stores, iron stored in iron-binding complexes, or both, and are typically also referred to as iron storage parameters. Iron storage parameters can include, for example, hematocrit (Hct), packed cell volume (PCV), hemoglobin concentration (Hb, also referred to as hemoglobin level), total iron-binding capacity (TIBC), transferrin saturation (TSAT), serum iron level, liver iron level, spleen iron level, and serum ferritin level. Of these, Hct, Hb, TIBC, TSAT, and serum iron level are commonly known as parameters that measure circulating iron stores. Liver iron level, spleen iron level, and serum ferritin level are commonly referred to as parameters that measure storage iron or iron stored in iron-binding complexes.

[0054] It should be noted that the above blood parameters are quantified in serum, but can be quantified in plasma as well. Serum and plasma levels are correlated and can be converted into each other.

[0055] ID is typically diagnosed prior to anemia based on early indicators of iron, such as reticulocyte hemoglobin content or reticulocyte hemoglobin equivalent (denoted CHr and RET-He, respectively, depending on the analyzer used). Recent studies have investigated this parameter in dog blood and found good correlations between low CHr / RET-He and other available indicators of iron deficiency and / or iron deficiency anemia (Fry and Kirk, 2006; Prins et al., 2009; Schaefer and Stokol, 2015; Fuchs et al., 2017; Steinberg and Olver, CS 2005). In some embodiments, iron-deficient subjects have a CHr / RET-He of 20 pg or less. IDA is typically diagnosed based on a complete blood count measured from a blood sample of the subject. The focus is on red blood cell parameters such as Hb, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), as well as Hct / PCV and red blood cell (RBC) count; however, leukopenia and thrombocytosis with IDA are possible. Iron deficiency anemia in dogs, for example, is characterized by reduced hemoglobin concentration with red blood cell microcytosis and hypochromasia (Bohn, 2013). Blood smears are used to confirm hypochromemia. Anemia may be corrected with IDA, but erythropoiesis is ineffective. Thus, reticulocytosis as well as polychromatosis are present with IDA.

[0056] Conveniently, an automated hematology analyzer is utilized to report blood parameters including total RBC count in the sample, Hb, Hct, MCV, MCHC, and additional blood parameters by flow cytometry (e.g., CHr / RET-He). In many countries, at least one of four parameters is measured to determine the presence or absence of IDA: MCV, MCHC, Hb, and RBC count. In some countries, CHr / RET-He may be used to determine the presence of IDA. A predefined threshold is set for Hb, and if a subject's hemoglobin level falls below that value, IDA may be diagnosed.

[0057] Hemoglobin concentration or level (Hb) is the total amount of hemoglobin per volume of blood. In healthy subjects, typical Hb ranges are as follows: for women, Hb=12.0-15.5 g / dL; for men, Hb=13.5-17.5 g / dL; for dogs, Hb=11.9-18.9 g / dL; for cats, Hb=9.8-15.4 g / dL; for horses, Hb=10.1-16.1 g / dL. However, in subjects with iron deficiency, hemoglobin concentrations can be significantly reduced. In some embodiments, the Hb of an iron-deficient dog is less than 6 g / dL (indicating the dog has severe IDA); in the range of 6-9 g / dL (indicating the dog has moderate IDA), or in the range of 9-11 g / dL (indicating the dog has mild IDA).

[0058] Mean corpuscular hemoglobin concentration (MCHC) is a measure of the average concentration of hemoglobin in red blood cells and is determined by the amount of hemoglobin protein in a given volume of packed red blood cells. It is typically calculated by dividing the hemoglobin concentration by the hematocrit. In healthy subjects, typical MCHC ranges are as follows: for women, MCHC=31-35 g / dL; for men, MCHC=31-35 g / dL; for dogs, MCHC=32.0-36.3 g / dL; for cats, MCHC=30-36 g / dL; for horses, MCHC=35.3-39.3 g / dL. However, in subjects with iron deficiency, MCHC can be significantly reduced. In some embodiments, the MCHC of an iron-deficient dog is less than 30 g / dL.

[0059] Mean corpuscular volume (MCV) is a measure of the average volume of red blood cells. It is typically calculated by multiplying the volume of blood by the percentage of cellular blood (hematocrit) and dividing the product by the number of red blood cells in that volume. In healthy subjects, typical MCV ranges are as follows: for women, MCV=80-100 g / dL; for men, MCV=80-100 fL; for dogs, MCV=66-77 fL; for cats, MCV=39-55 fL; for horses, MCV=37.3-49.0 fL. However, in iron-deficient subjects, MCV can be significantly reduced. In some embodiments, iron-deficient dogs have an MCV below 60 fL (indicating that the dog suffers from severe IDA).

[0060] In some embodiments, subjects undergoing treatment with the methods disclosed herein experience an increase in hemoglobin concentration. In some embodiments, the present disclosure provides a method of increasing hemoglobin concentration in a subject in need thereof, the method comprising administering to the subject an iron complex compound, wherein the iron complex compound results in an increase in hemoglobin concentration in the subject.

[0061] In some embodiments, the iron complex compound provides a mean increase in hemoglobin concentration at 3 weeks (21 days) after administration of more than 0.5 g / dL, more than 0.6 g / dL, more than 0.7 g / dL, more than 0.8 g / dL, more than 0.9 g / dL, more than 01.0 g / dL, more than 1.1 g / dL, more than 1.2 g / dL, more than 1.3 g / dL, more than 1.4 g / dL, more than 1.5 g / dL, more than 1.6 g / dL, more than 1.7 g / dL, more than 1.8 g / dL, or more than 1.9 g / dL.

[0062] In some embodiments, the iron complex compound provides a mean increase in hemoglobin concentration at 3 weeks (21 days) after administration of less than 7.0 g / dL, less than 6.0 g / dL, less than 5.0 g / dL, less than 4.5 g / dL, less than 4.0 g / dL, or less than 3.5 g / dL.

[0063] In some embodiments, the iron complex compound provides a mean increase in hemoglobin concentration of 0.5 to 7.0 g / dL, 1.0 to 6.0 g / dL, 1.3 to 5.0 g / dL, 1.5 to 4.5 g / dL, 1.7 to 4.0 g / dL, or 1.9 to 3.5 g / dL three weeks (21 days) after administration.

[0064] The mean increase in hemoglobin concentration at 1 week is expected to be 0.5 to 2.0 g / dL lower than the mean increase at 3 weeks. The mean increase in hemoglobin concentration at 4 or 8 weeks after dosing is expected to be approximately the same as the mean increase at 3 weeks after dosing.

[0065] The above-mentioned mean increase in hemoglobin concentration is particularly applicable to the treatment of companion animals, preferably canines and felines, most preferably dogs.

[0066] In veterinary medicine, Hct or PCV are traditionally used as parameters to evaluate anemia and its severity, instead of Hb concentration, which is mainly used in human medicine (Tvedten, 2010). Hct / PCV generally has an acceptable reliability in this respect, but is less accurate than Hb. PCV, also known as microhematocrit, is measured directly after centrifugation of a capillary tube filled with anticoagulated blood, while Hct obtained by a hematology analyzer is calculated as follows: Hct = (MCV × RBC count) ÷ 10. Nevertheless, under most conditions Hb and PCV / Hct are closely related, such that Hb (g / dL) ≒ 1 / 3 × Hct (%). To eliminate potential inaccuracies, blood Hb concentration should be considered as the main parameter in the evaluation of anemia in companion animals.

[0067] Hct / PCV, also called packed cell volume or packed cell volume fraction, is the volume percentage of red blood cells in blood. For example, in healthy dogs, Hct / PCV is typically 35-57% of the blood volume. In healthy cats, Hct / PCV is typically 30-45% of the blood volume, and in healthy horses, Hct / PCV is typically 27-43% of the blood volume. However, in iron-deficient subjects, Hct / PCV is often significantly depleted due to iron malabsorption and / or reduced iron storage capacity. In some embodiments, the Hct / PCV of iron-deficient dogs is less than 18% (indicating the dog has severe IDA); in the range of 18% to 27% (indicating the dog has moderate IDA), or in the range of 27% to 35% (indicating the dog has mild IDA).

[0068] The iron complex compounds disclosed herein can be administered to a subject to increase Hct / PCV. The exact timing of administration will necessarily vary from subject to subject, depending, for example, on the severity of iron deficiency the subject is experiencing, the level of iron absorption the subject is or is not experiencing, the judgment of the treating health care professional, etc. In some embodiments, the disclosure provides a method of increasing Hct / PCV in a subject in need thereof, the method comprising administering an iron complex compound to the subject, wherein the iron complex compound results in an increase in the subject's Hct / PCV. In some embodiments, the increase is 1% to 30%, 1% to 15%, 1% to 12%, 1% to 10%, 1% to 9%, 1% to 8%, 1% to 7%, 1% to 6%, 1% to 5%, 1% to 4%, 1% to 3%, or 1% to 2%.

[0069] In addition to these parameters, measurement of serum ferritin can help in the diagnosis of IDA. Liver ferritin stores are the main source of stored iron in the body. Ferritin is an intracellular protein that stores iron and releases it in a controlled manner. Medically, the amount of ferritin present in a blood sample and / or liver tissue sample reflects the amount of iron stored in the liver (although ferritin is ubiquitous and can be found in many other tissues in the body in addition to the liver). Ferritin serves to store iron in a non-toxic form in the liver and transport it to areas where it is needed. Low ferritin levels generally indicate iron deficiency anemia. However, because ferritin is also an acute phase protein, it may be elevated by underlying inflammatory diseases, so normal ferritin levels do not exclude IDA. While ferritin measurement is fully standardized in human medicine, no standardized reference ranges for canine serum ferritin exist, although several veterinary hematology laboratories, such as the Kansas State University Veterinary Diagnostic Laboratory ( http: / / www.ksvdl.org / laboratories / comparative-hematology / - accessed September 10, 2019 and July 6, 2021), have developed ELISA-based assays for canine ferritin.

[0070] For example, in healthy humans, normal ferritin serum levels, also referred to as the reference range, are typically 15 to 300 ng / mL for adult men and 12 to 250 ng / mL for adult women. However, in subjects with iron deficiency, serum ferritin levels are typically significantly reduced due to a decrease in the amount of iron stored in the liver available for binding to ferritin, which occurs as the body loses its ability to absorb and store iron.

[0071] The term "serum ferritin" (s-ferritin) as used herein refers to the level of ferritin in serum measured using a species-specific two-site immunoenzymatic ("sandwich") assay or another reliable quantitative serum ferritin assay. Ferritin is the body's major iron storage protein. The concentration of ferritin is directly proportional to the body's total iron stores, making serum ferritin levels a common diagnostic tool for assessing iron status. Subjects with iron deficiency anemia have serum ferritin levels approximately one-tenth that of normal subjects. Ferritin levels also provide a sensitive means of detecting iron deficiency at an early stage.

[0072] In some embodiments, subjects undergoing treatment with the methods disclosed herein experience an increase in serum ferritin levels. In some embodiments, the present disclosure provides a method of increasing serum ferritin in a subject in need thereof, the method comprising administering to the subject an iron-complex compound, wherein the iron-complex compound results in an increase in serum ferritin.

[0073] In some embodiments, the iron complex compound provides a mean increase in serum ferritin at 4 or 8 weeks post-treatment of greater than 100 ng / mL, greater than 110 ng / mL, greater than 120 ng / mL, greater than 130 ng / mL, greater than 140 ng / mL, greater than 150 ng / mL, greater than 160 ng / mL, greater than 170 ng / mL, greater than 180 ng / mL, greater than 190 ng / mL, or greater than 200 ng / mL.

[0074] In some embodiments, the iron complex compound provides a mean increase in serum ferritin selected from less than 400 ng / mL, less than 390 ng / mL, less than 380 ng / mL, less than 370 ng / mL, less than 360 ng / mL, less than 350 ng / mL, less than 340 ng / mL, less than 330 ng / mL, less than 320 ng / mL, less than 310 ng / mL, less than 300 ng / mL, less than 290 ng / mL, less than 280 ng / mL, less than 270 ng / mL, less than 260 ng / mL, or less than 250 ng / mL at 4 weeks or 8 weeks post-treatment.

[0075] In some embodiments, the iron complex compound provides a mean increase in serum ferritin of 100 to 400 ng / mL, 100 to 375 ng / mL, 100 to 350 ng / mL, 100 to 325 ng / mL, 100 to 300 ng / mL, 100 to 275 ng / mL, or 150 to 300 ng / mL at 4 or 8 weeks post-treatment.

[0076] In some embodiments, the iron complex compound provides a mean increase in serum ferritin one week after treatment that is greater than 200 ng / mL, greater than 230 ng / mL, greater than 260 ng / mL, greater than 290 ng / mL, greater than 320 ng / mL, greater than 350 ng / mL, greater than 380 ng / mL, greater than 410 ng / mL, or greater than 440 ng / mL.

[0077] In some embodiments, the iron complex compound provides a mean increase in serum ferritin selected from less than 600 ng / mL, less than 590 ng / mL, less than 580 ng / mL, less than 570 ng / mL, less than 560 ng / mL, less than 550 ng / mL, less than 540 ng / mL, less than 530 ng / mL, less than 520 ng / mL, less than 510 ng / mL, less than 500 ng / mL, less than 490 ng / mL, less than 480 ng / mL, less than 470 ng / mL, less than 460 ng / mL, or less than 450 ng / mL one week after treatment.

[0078] In some embodiments, the iron complex compound provides a mean increase in serum ferritin one week after treatment of 200 to 600 ng / mL, 250 to 600 ng / mL, 300 to 600 ng / mL, 350 to 600 ng / mL, or 400 to 600 ng / mL.

[0079] The mean increase in serum ferritin is particularly applicable to the treatment of humans, with similar values ​​being applicable to companion animals, particularly canines and felines, most preferably dogs.

[0080] In addition to stored iron, small amounts of iron circulate in the plasma bound to a protein called transferrin. Thus, serum iron (s-iron) levels can be represented by the amount of iron circulating in the blood bound to the protein transferrin. Transferrin is a glycoprotein produced by the liver that can bind one or two ferric (iron(III) or Fe3+) ions. It is the most prevalent in blood and is the dynamic carrier of iron, and therefore an essential component of the body's ability to transport stored iron for use throughout the body. Transferrin saturation (or TSAT) is measured as a percentage and is calculated by multiplying the ratio of serum iron to total iron binding capacity by 100. This value allows the clinician to know how much serum iron is actually bound to the total amount of transferrin available for iron binding. For example, a TSAT value of 35% means that 35% of the available iron-binding sites on transferrin in the blood sample are occupied by iron. For example, in healthy dogs, typical TSAT values ​​are around 15-50%. However, in iron-deficient subjects, TSAT levels are typically significantly reduced due to a decrease in the amount of iron available for binding by transferrin, as the body loses its ability to absorb and store iron, hi some embodiments, iron-deficient subjects have TSAT levels below 20% and / or ferritin levels <100 μg / L.

[0081] In some embodiments, subjects undergoing treatment with the methods disclosed herein experience an increase in TSAT levels. In some embodiments, the disclosure provides a method of increasing TSAT in a subject in need thereof, the method comprising administering to the subject an iron complex compound, wherein the iron complex compound results in an increase in TSAT in the subject.

[0082] In some embodiments, the iron-complex compounds provide a mean increase in TSAT at 4 or 8 weeks post-treatment that is greater than 1%, greater than 1.5%, greater than 2%, or greater than 2.5%.

[0083] In some embodiments, the iron-complex compound provides a mean increase in TSAT of less than 5%, less than 4%, or less than 3% at 4 or 8 weeks post-treatment.

[0084] In some embodiments, the iron complex compound provides a mean increase in TSAT of 1 to 5%, 1.5 to 4%, or 2 to 3% at 4 or 8 weeks post-treatment.

[0085] In some embodiments, the iron-complex compounds provide a mean increase in TSAT one week after treatment that is greater than 5%, greater than 6%, or greater than 7%.

[0086] In some embodiments, the iron-complex compound provides a mean increase in TSAT one week after treatment of less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, or less than 15%.

[0087] In some embodiments, the iron complex compounds provide a mean increase in TSAT one week after treatment of 5 to 20%, or 5 to 15%.

[0088] In suspicious situations where the information gathered does not completely exclude causes of anemia other than iron deficiency, a bone marrow aspirate may be considered. The absence of stainable iron in the bone marrow may indicate that the dog has insufficient iron for erythropoiesis.

[0089] Companion animals particularly suitable for treatment with the present invention are those that have one or more of the following: - Hemoglobin concentration (Hb) less than 11 g / dL; - Hematocrit (Hct / PCV) less than 35%; - Mean corpuscular volume (MCV) less than 60 fL; - Reticulocyte hemoglobin content (CHr) / reticulocyte hemoglobin equivalent (RET-He) less than or equal to 20 pg; and / or - Mean corpuscular hemoglobin concentration (MCHC) less than or equal to 30 g / dL.

[0090] In some embodiments, a subject undergoing treatment with the methods disclosed herein may experience improvement in iron deficiency and / or iron deficiency anemia as Hb is raised and / or maintained above a threshold level. In some embodiments, methods of treating iron deficiency and / or iron deficiency anemia are disclosed, the methods comprising administering to a subject an iron complex compound, wherein the iron complex compound provides one or more of the following: - Hemoglobin concentration (Hb) of 11 g / dL or more; - Hematocrit (Hct / PCV) of 35% or more; - Mean corpuscular volume (MCV) of 60 fL or more; - Reticulocyte hemoglobin content (CHr) / reticulocyte hemoglobin equivalent (RET-He) greater than 20 pg; and / or - Mean corpuscular hemoglobin concentration (MCHC) greater than 30 g / dL.

[0091] The present disclosure provides methods of improving one or more iron storage parameters in a subject in need thereof, wherein the at least one iron storage parameter can be selected from serum ferritin level, transferrin saturation (TSAT), hemoglobin concentration, hematocrit, total iron binding capacity, iron absorption level, serum iron level, liver iron level, splenic iron level, and combinations thereof.

[0092] In one embodiment, the at least one iron storage parameter is hemoglobin concentration, and improving comprises increasing the hemoglobin concentration in the subject. In another embodiment, the at least one iron storage parameter is transferrin saturation, and improving comprises increasing transferrin saturation in the subject. In yet another embodiment, the at least one iron storage parameter is serum ferritin level, and improving comprises increasing serum ferritin level in the subject.

[0093] [Iron complex compounds] Described herein are methods of treatment, i.e., methods of treating iron deficiency, that include administering an iron complex compound and a combination of the iron complex compound with an additional drug, where the iron complex compound has certain properties and thus exerts a certain effect in the subject being treated. Thus, the methods of the invention are applicable to complexes that share said properties. For example, the iron complex compound should be relatively stable; should have good absorption properties; and should exhibit low urinary excretion.

[0094] Unless further specified, the term "iron complex compound" as used herein refers to any complex of iron ions or particles comprising Fe3+ and / or Fe2+ and one or more ligands. The iron atom is bound in a coordination complex through ionic and coordinate covalent bonds with the ligands or as part of a polynuclear iron ligand nanomolecule, preferably an iron sugar nanomolecule.

[0095] [Ligand] Advantageously, the ligands and salts used in the iron complex compounds of the present invention, as well as the carriers and other components of the compositions, are physiologically acceptable. As used herein, the term "physiologically acceptable" means that the ligand, salt, carrier or other component does not cause acute toxicity when a therapeutically effective amount of the iron complex compound or a composition containing the ligand, salt, carrier or other component is administered to a subject.

[0096] [sugar] According to one group of embodiments, the ligand in the iron complex compound is a sugar.

[0097] Unless further specified, the term "sugar" as used herein includes sugars that are reduced, oxidized, derivatized, or combinations thereof, as described herein. In particular, sugars can be derivatized, for example, by forming ethers, amides, esters, and amines at the hydroxyl groups of the sugar, or by converting the aldehyde groups of the sugar to glycol groups to form heptonic acid. Thus, the term "sugar" as used herein refers to a sugar having the empirical formula C m (H2O) nwhere m and n are integers that may be the same or different.

[0098] Sugars that can be used as ligands in the iron-sugar complexes of the present invention include, for example, monosaccharides; disaccharides, such as sucrose, maltose or isomaltose; oligosaccharides and polysaccharides, such as maltodextrin, polyglucose, dextran, oligomaltose, oligoisomaltose; sugar alcohols, such as sorbitol and mannitol; sugar acids and their salts, such as gluconic acid, gluconate, dextran glucoheptonic acid, dextrin glucoheptonic acid, dextran glucoheptonate and dextrin glucoheptonate, and or their reduced and / or oxidized and / or derivatized variants, such as carboxymaltose, polyglucose sorbitol carboxymethyl ether, hydrogenated dextran, oxidized dextran, carboxyalkylated oligosaccharides and polysaccharides, oxidized oligosaccharides and polysaccharides, hydrogenated dextrin, oxidized dextrin, hydrogenated oligomaltose, hydrogenated oligoisomaltose, hydrogenated oligomaltose, hydroxyethyl starch, hydroxyethyl starch carrying heptonic acid moieties, or mixtures of two or more thereof. When oligosaccharides and polysaccharides are used, they typically comprise mixtures of oligosaccharides and polysaccharides with various chain lengths. Thus, these oligosaccharides and polysaccharides can be conveniently characterized by their weight-average or number-average molecular weight, and the distribution of these molecules over a range of molecular weights. For simplicity, reference to oligosaccharides or polysaccharides is meant to refer to such mixtures.

[0099] The term "oligosaccharide" as used herein generally refers to a sugar or reduced and / or oxidized and / or derivatized variant thereof having a small number of monosaccharide units, typically between 3 and 10, or a mixture of two or more sugars or reduced and / or oxidized and / or derivatized variants thereof, where the majority of the molecules (e.g., at least 60%, at least 70%, or at least 80%) have a small number of monosaccharide units, typically between 3 and 10.

[0100] The term "monomeric sugar" as used herein refers to a monosaccharide or a reduced and / or oxidized and / or derivatized variant thereof, or a mixture of two or more monosaccharides and / or variants thereof.

[0101] The term "dimeric sugar" as used herein refers to a sugar having two monosaccharide units (such as a disaccharide), or a reduced and / or oxidized and / or derivatized variant thereof, or a mixture of two or more sugars, or reduced and / or oxidized and / or derivatized variants thereof, where the molecule has two monosaccharide units.

[0102] Sugar alcohols are mono- or disaccharide derivatives in which the aldehyde group has been converted to a hydroxyl group.

[0103] Sugar acids are monosaccharide derivatives that have a carboxyl group, which can be obtained, for example, by oxidizing the aldehyde group of an aldose to form an aldonic acid, the 1-hydroxyl group of a 2-ketose to form an α-keto acid (urosonic acid), the terminal hydroxyl group of an aldose or ketose to form an uronic acid, or by oxidizing both ends of an aldose to form an aldaric acid.

[0104] Preferably, the content of reducing aldehyde groups in the sugar is at least partially reduced. This can be achieved by hydrogenation, oxidation, glycosylation, or a combination thereof. Iron-sugar complex compounds containing hydrogenated and / or oxidized sugars can be prepared, for example, as described in WO 99 / 48533 A1; WO 2010 / 108493 A1 or WO 2019 / 048674 A1, all of which are incorporated by reference. The amount of reducing sugars can be quantified using Somogyi's reagent.

[0105] Specifically, aldehyde groups can be converted to hydroxyl groups by hydrogenation, for example by reacting the sugar with a reducing agent such as sodium borohydride in aqueous solution, or by reacting with hydrogen in the presence of a hydrogenation catalyst such as Pt or Pd.

[0106] Alternatively or in addition to hydrogenation, the aldehyde group can be oxidized by oxidation of the sugar using an aqueous solution of hypochlorite, chlorite or hypobromite at a pH in the alkaline range, for example in the range of pH 8 to pH 12, in particular pH 9 to pH 11. Suitable hypochlorites include, for example, alkali metal hypochlorites, such as sodium hypochlorite, and the same applies to chlorite and hypobromite. The aqueous solution of hypochlorite, chlorite or hypobromite can have a concentration, calculated as active chlorine, of, for example, at least 13% by weight, in particular in the range of 13 to 16% by weight. The oxidation reaction can be carried out at a temperature in the range of, for example, 15 to 40° C., preferably 25 to 35° C. The reaction time can be, for example, in the range of 10 minutes to 4 hours, for example, 1 to 1.5 hours. The addition of catalytic amounts of bromide ions, for example in the form of an alkali metal bromide, such as sodium bromide, can accelerate the oxidation reaction, but is not essential.

[0107] The aldehyde groups of the sugar can be converted by both hydrogenation and oxidation. This can be accomplished, for example, by first hydrogenating the sugar to convert some of the aldehyde groups to hydroxyl groups, and then oxidizing substantially all of the remaining aldehyde groups to carboxyl groups. When the sugar is a polysaccharide such as dextran, the average molecular weight of the iron-sugar complex formed therewith can be influenced by adjusting the ratio of hydrogenated and oxidized aldehyde groups. To obtain a stable product, the amount of reducing groups in the sugar (such as dextran) before oxidation should not exceed 15% by weight.

[0108] Sugars, including reduced and / or oxidized sugars, can be derivatized by forming, for example, ethers, amides, esters, and amines with the hydroxyl groups of the sugar. In certain embodiments, sugars are derivatized by forming carboxyalkyl ethers, particularly carboxymethyl ethers, with the hydroxyl groups of the sugar. The use of carboxymethylated sugars in products, such as the iron-sugar complex compounds of the invention, can reduce the toxicity of the products when administered parenterally to a subject, as compared to products containing the corresponding non-carboxylated sugars.

[0109] In a preferred embodiment, the sugar is carboxymaltose, polyglucose sorbitol carboxymethyl ether, dextran, hydrogenated dextran, dextran glucoheptonate, dextran glucoheptonate, dextrin, hydrogenated dextrin, dextrin glucoheptonate, dextrin glucoheptonate, oligoisomaltose, hydrogenated oligoisomaltose, hydroxyethyl starch, hydrogenated hydroxyethyl starch, hydroxyethyl starch with heptonic acid moieties, hydroxypropyl starch, hydrogenated hydroxypropyl starch, hydroxypropyl starch with heptonic acid moieties, or a mixture of two or more thereof.

[0110] Such sugars typically have a weight average molecular weight (M) of 500 to 80,000 Da, for example 800 to 40,000 Da or 800 to 10,000 Da, in particular 800 to 3,000 Da. W In certain embodiments, the saccharide will have a weight average molecular weight (M) of 500 to 7000 Da, such as 500 to 3000 Da, 700 to 1400 Da, in particular 850 to 1150 Da, such as about 1000 Da, or 1150 to 1350 Da, such as about 1250 Da. W ) polysaccharides or oligosaccharides or mixtures thereof.

[0111] The amount of dimers (disaccharides) in a sugar preparation, which is an oligosaccharide or polysaccharide preparation (optionally reduced and / or oxidized and / or derivatized), is considered to be an important factor for the physiological iron release rate from the iron-sugar complex compound prepared therefrom. See WO 2010 / 108493 A1. Thus, when the sugar is an oligosaccharide or polysaccharide preparation (optionally reduced and / or oxidized and / or derivatized), such as the hydrogenated polysaccharide / oligosaccharide disclosed herein, the content of dimeric sugars in said preparation is preferably 2.9% by weight or less, in particular 2.5% by weight or less, in particular 2.3% by weight or less, based on the total weight of the sugar. It is also preferred that the content of monomeric sugars in the sugar preparation is 0.5% by weight or less, based on the total weight of the sugar. This reduces the risk of toxic effects caused by free iron ions released from the compound after parenteral administration.

[0112] Particularly preferred sugar ligands are described below.

[0113] [Oligoisomaltose] In a particularly preferred embodiment, the sugar is oligoisomaltose, or even more preferably hydrogenated oligoisomaltose (ie, oligoisomaltoside).

[0114] In a particular embodiment, the oligoisomaltose (toside) has a weight average molecular weight (M) of 700 to 1500 Da. W 850 to 1150 Da; preferably 950 to 1050 Da, most preferably 975 to 1025 Da, for example about 1000 Da. W Oligoisomaltose (toside) having a weight average molecular weight (M) of 1150 to 1350 Da; preferably 1200 to 1300 Da, most preferably 1225 to 1275 Da; for example, about 1250 Da. W Oligoisomaltose(toside) (also referred to herein as "octasaccharide") having a weight average molecular weight (M) of 850 to 1150 Da represents another specific embodiment. WFor oligoisomaltose (tosides) having a weight average molecular weight (M) of 1150 to 1350 Da, it is preferred that the fraction having more than 9 monosaccharide units is less than 30%, preferably less than 25%, most preferably less than 20% by weight of the oligosaccharides; for example, 5% to 15%. W For oligoisomaltose (tosides) having more than 9 monosaccharide units, it is preferred that the fraction having more than 9 monosaccharide units is less than 40%, preferably less than 35%, most preferably less than 30%; for example, 20 to 30% of the weight of the oligosaccharides. According to another embodiment, the content of monomers and dimers (fraction having less than 3 monosaccharide units) is less than 10.0%, preferably less than 3.0%, most preferably less than 1.0%; for example, 0.1 to 0.5% of the weight of the oligosaccharides.

[0115] Oligoisomaltose(tosides) in which the majority of the molecules (e.g. at least 40% by weight or preferably at least 50%, e.g. 40 to 70% or 50 to 70%) have 3 to 6 monosaccharide units represent one preferred embodiment. W ). Thus, in a preferred embodiment of the invention, the ligand is an oligoisomaltose (toside) in which the major proportion (for example at least 40% by weight, or preferably at least 50%, for example 40 to 70% or 50 to 70%) of the optionally hydrogenated oligoisomaltose molecules has 3 to 6 monosaccharide units. More specifically, said proportion of molecules having 3 to 6 monosaccharide units is higher than the proportion of molecules having 6 to 10 monosaccharide units. An example of such an oligosaccharide is isomaltoside 1000 (INN name: del-isomaltose).

[0116] Oligoisomaltose(tosides) (herein also called "octasaccharides"), the major proportion of the molecules (e.g. at least 40% by weight or preferably at least 45%, e.g. 40 to 60% or 45 to 55%) having 6 to 10 monosaccharide units, represent another preferred embodiment. This is especially true for oligoisomaltose(tosides) having a weight average molecular weight (M) of 1150 to 1350. W) in a preferred embodiment of the invention. Thus, in a preferred embodiment of the invention, the ligand is an oligoisomaltose (toside) in which a major proportion (e.g. at least 40% by weight, e.g. 40 to 60%) of the optionally hydrogenated oligoisomaltose molecules have 6 to 10 monosaccharide units. More specifically, said proportion of molecules having 6 to 10 monosaccharide units is greater by weight than the proportion of molecules having 3 to 6 monosaccharide units. An example of such an oligosaccharide is the octasaccharide disclosed herein.

[0117] The oligoisomaltose (oligoisomaltoside) of the present invention is preferably hydrogenated oligoisomaltose (oligoisomaltoside). Typically, the amount of reducing sugars in such hydrogenated oligoisomaltose (oligoisomaltoside) is 2.5% or less, preferably 1.0% or less, most preferably 0.5% or less, by weight of the oligosaccharide; for example, about 0.3%. Before hydrogenation, the amount of reducing sugars in the oligoisomaltose is at least 10% by weight of the oligosaccharide, usually at least 15%. However, the amount of reducing sugars also depends on the molecular weight distribution of the sugar chain. The shorter the chain, the higher the amount of reducing sugars, while the longer the chain, the lower the amount of reducing sugars. Thus, it is a particular embodiment of the present invention that the amount of reducing sugars in the oligoisomaltose is less than 35%, preferably 30% or less, by weight of the oligosaccharide; for example, in the range of 10% to 30%, preferably in the range of 15 to 25%.

[0118] [Gluconic acid derivatives] Another specific sugar ligand for use in the present invention is a gluconic acid derivative of a sugar such as dextran or dextrin. Examples include bepectate or dextran glucoheptonate. The term "bepectate" as used herein refers to a hydroxyethyl-amylopectin (starch) derivative. Bepectate is also called polyglucoferone. Bepectate is disclosed, for example, in WO 2012 / 175608, which is incorporated by reference in its entirety. Such hydroxyethyl-amylopectin (starch) derivatives can have many heptonate residues per molecule, depending on the number of terminal glucosyl residues present in the starch molecule. The heptonate residues increase the hydrophilicity of the hydroxyethyl starch and enhance the stability of the complex formed by the hydroxyethyl starch with a ligand, such as a metal ion, for example an iron ion. More generally, hydroxyethyl starch (HES) is a starch in which some of the hydroxyl groups of a single glucosyl residue are replaced by hydroxyethyl residues. The modification with heptonate residues is carried out by converting the terminal glucosyl residues of hydroxyethyl starch into heptonate residues. Preferably, the hydroxyethyl starch used in the method has a weight average molecular weight (Mw) of less than 200000 g / mol, in particular less than 130000 g / mol, in particular less than 100000 g / mol, in particular less than 90000 g / mol, in particular less than 80000 g / mol, and more particularly less than 75000 g / mol. Very suitable molecular weights are in the range of 55000 g / mol to 85000 g / mol. Such hydroxyethyl starches have a relatively low molecular weight compared to the (unmodified) hydroxyethyl starches currently used in the medical field. A suitable method for quantifying the molecular weight of hydroxyethyl starch is size exclusion chromatography (SEC). In a preferred embodiment, the hydroxyethyl starch has an average molar degree of substitution of 0.4 to 0.6, in particular 0.45 to 0.55. An average molar degree of substitution of about 0.50 is particularly preferred. The average molar degree of substitution is a measure of the amount of hydroxyl groups replaced by hydroxyethyl residues per glucosyl residue.Since there are three hydroxyl groups in each glucose unit (or glucosyl residue), the average molar substitution can be up to 3. An average molar substitution of 0.5 indicates that in each second glucosyl residue (on an average or statistical basis), one hydroxyl group is replaced by a hydroxyethyl residue. In a preferred embodiment, the hydroxyethyl starch has a weight average molecular weight (Mw) of 55000 to 85000 g / mol, preferably about 70000 g / mol, and an average molar substitution of 0.45 to 0.55, in particular about 0.50. Such a hydroxyethyl starch having a molecular weight of 70000 g / mol ± 15000 g / mol and an average molar substitution of 0.5 ± 0.05 can also be called HES70 / 0.5.

[0119] Dextran glucoheptonate, dextran glucoheptonate, dextrin glucoheptonate, and dextrin glucoheptonate are further examples of suitable sugar ligands in which a sugar such as a dextran or dextrin is modified to bear a heptonic acid residue.

[0120] [Polymer ligand] According to another group of embodiments, the ligand is a suitable ligand for the ligand-substituted oxo-hydroxy iron complex compound. Suitable ligands include, for example, carboxylic acids, such as adipic acid, glutaric acid, tartaric acid, malic acid, succinic acid, aspartic acid, pimelic acid, citric acid, gluconic acid, lactic acid, and benzoic acid; food additives, such as maltol, ethyl maltol, and vanillin; anions with ligand properties, such as bicarbonate, sulfate, and phosphate; mineral ligands, such as silicate, borate, molybdate, and selenate; amino acids, especially protein-forming amino acids such as tryptophan, glutamine, proline, valine, histidine, and the like; and nutrient-based ligands, such as folate, ascorbate, pyridoxine, niacin, and the like; and mixtures of two or more thereof. Specific examples of suitable polymeric ligands include biocompatible polyethylene glycol-based polymers, as described in U.S. Pat. No. 8,741,615 B2, namely those of the general formula (I): TIFF2024529536000001.tif41170, where R1 is alkyl, aryl, carboxyl, or amino, R2 is alkyl or aryl, n is an integer from 5 to 1000, and m is an integer from 1 to 10. Suitable alkyl groups for R1 and R2 include C1-C 20 Straight or branched alkyl groups are included. In one embodiment, each of R1 and R2 is independently a C1-C6 straight or branched alkyl, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, n-hexyl, and isohexyl. Aryl groups suitable for R1 and R2 include C6-C6 straight or branched alkyl, such as methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, n-hexyl, and isohexyl. 12 Substituted or unsubstituted aryl groups include, for example, phenyl, biphenyl, and naphthyl, and examples of the substituents include hydroxyl, haloalkyl, alkoxyl, cyano, nitro, amino, or alkylamino. The number of methylene units, m, is preferably an integer from 1 to 10. The number of oxyethylene units, n, is preferably an integer from 5 to 1000, corresponding to a PEG molecular weight of 200 to 50000 g / mol. In one embodiment, m is about 3 and n is about 15.

[0121] Biocompatible polymers are useful in that the surface of the iron oxide nanoparticles can be chemically modified to provide a biocompatible magnetic material comprising the magnetic nanoparticles and a biocompatible polymer.

[0122] [Sugar preparation] The manufacture of most of the sugars disclosed herein requires preparation from readily available sugars. Common starting materials are dextrans and dextrins, i.e., polyglucoses with predominantly α-1,6- or α-1,4-linked glucose units, respectively. The dextrans and dextrins used as starting materials are typically high molecular weight polysaccharides, and therefore usually require hydrolysis and fractionation of the resulting hydrolysates to tailor the molecular weight of the desired sugar.

[0123] A typical process for producing oligoisomaltose (toside) of the present invention comprises the following steps: (a) hydrolyzing dextran to obtain a hydrolysate; (b) fractionating the hydrolysate to obtain oligoisomaltose; and optionally (c) hydrogenating the oligoisomaltose to obtain oligoisomaltoside.

[0124] A further optional step is as follows: reducing the levels of mono- and disaccharides in the oligoisomaltosides, for example by purification by diafiltration; Obtaining purified oligoisomaltose or oligoisomaltoside, for example by purification by ion exchange.

[0125] For example, oligoisomaltose (toside), such as the octasaccharide of the present invention, can be produced from dextran fractions that are combined and fractionated by ultrafiltration. The dextran fractions have weight average molecular weights (M) ranging from 500 to 2000 kDa. w ), which is hydrolyzed to have a Mw in the range of 20,000 to 70,000 Da. In one or more steps, the starting material can be hydrolyzed to a lower molecular weight, fractionated and filtered until the desired molecular weight distribution is achieved. The resulting oligoisomaltose can then be hydrogenated to obtain oligoisomaltosides. Purification by diafiltration serves to reduce the levels of mono- and disaccharides, and the resulting product can be further purified, for example by ion exchange. For example, low amounts of mono- and disaccharides can be achieved by removing the smaller sugar molecules from the sugar preparation by membrane filtration, for example using a membrane with a cut-off value in the range of 340-800 Da. The concentration of mono- and disaccharides in the fractions obtained by the purification method can be monitored by gel permeation chromatography.

[0126] The preparation of bepectate is disclosed, for example, in WO 2012 / 175608 A1. Briefly, hydroxyethyl starch is dissolved in water. Then, the pH value is adjusted to a value between 8.0 and 10.0. Then, a cyanide compound is added to the hydroxyethyl starch solution. Then, the solution is heated to a temperature between 80 and 99°C and maintained at this temperature for a first period of time. Finally, the pH value is adjusted to a value between 2.0 and 4.0, and the solution is brought to a temperature between 50 and 90°C and maintained at this temperature for a second period of time. The preparation of gluconic acid derivatives of dextran and dextrin is disclosed, for example, in US Pat. No. 3,639,588. The preparation of polyethylene glycol-based polymers is disclosed, for example, in US Pat. No. 8,741,615.

[0127] [Iron preparations] The iron preparations that can be used to make the iron complex compounds include iron in a form selected from water-soluble iron salts, iron hydroxide, and iron oxide hydroxide. The iron preparations can include a mixture of two or more of these iron forms.

[0128] In a particular embodiment, the iron preparation comprises a water-soluble iron salt, such as iron bromide, iron sulfate or iron chloride, in particular ferric chloride (FeCl3), ferrous chloride (FeCl2) or mixtures thereof. Advantageously, the water-soluble iron salt is a physiologically acceptable salt.

[0129] In a further particular embodiment, the iron preparation comprises an iron hydroxide, such as ferric hydroxide (Fe(OH)3), ferrous hydroxide (Fe(OH)2), or a mixture thereof.

[0130] In further particular embodiments, the iron preparation comprises ferric oxide hydroxide. The ferric oxide hydroxide may also be referred to as ferric oxyhydroxide. The ferric oxide hydroxide is a compound consisting of one or more iron ions, one or more oxo groups, and one or more hydroxyl groups. Particular ferric oxide hydroxides include, for example, ferric oxide hydroxides that exist in anhydrous (FeO(OH)) and hydrated (FeO(OH)·nH2O) forms, such as ferric oxide hydroxide monohydrate (FeO(OH)·H2O). The ferric oxide hydroxides can be prepared from aqueous solutions of iron(III) salts by hydrolysis and precipitation, for example as described in Roempp lexicon Chemie, 10. Auflage, 1997. The ferric oxide hydroxides can exist in various polymorphic forms. For example, polymorphs of FeO(OH) include α-FeO(OH) (goethite), β-FeO(OH) (akaganeite), γ-FeO(OH) (lepidocrocite), and δ-FeO(OH) (ferroxylite).

[0131] According to a particular embodiment, an iron preparation is used that is low in non-ferrous metal impurities. Suitable levels of such non-ferrous metal impurities are described in WO 2019 / 048674 A1. Such preparations include: (a) from iron pentacarbonyl; or (b) by recrystallization of the iron salt from its aqueous solution; or (c) by extracting the aqueous iron salt solution with an organic solvent; or (d) from iron precipitated at the anode during the electrolysis of aqueous iron salts; or (e) by contacting an aqueous iron salt solution with a base to form a precipitate of iron hydroxide and separating the precipitate from the liquid by filtration or centrifugation; or (f) It can be obtained by distilling ferric chloride from a mixture containing ferric chloride and nonvolatile impurities.

[0132] According to a preferred embodiment, the iron preparation is obtained by a process of extraction of an aqueous iron salt solution (eg obtained during the processing of iron-containing nickel ores for nickel production) with an organic solvent.

[0133] According to a particularly preferred embodiment, the iron preparation used in the method of the present invention is prepared from iron pentacarbonyl.

[0134] (a) from iron pentacarbonyl; or (b) by recrystallization of the iron salt from its aqueous solution; or (c) by extracting the aqueous iron salt with an organic solvent; or (d) from iron precipitated at the anode during the electrolysis of aqueous iron salts; or (e) by contacting an aqueous iron salt solution with a base to form a precipitate of iron hydroxide and separating the precipitate from the liquid by filtration or centrifugation; or (f) Production of the iron preparations described herein by distillation of ferric chloride from a mixture containing ferric chloride and non-volatile impurities can be a step in the process of the invention, although it is not required.

[0135] Methods for preparing water-soluble iron salts, iron hydroxides or iron oxide hydroxides from iron pentacarbonyl are known in the art. For example, in a first step, iron pentacarbonyl can be decomposed to form iron (so-called iron carbonyl) at high temperatures (e.g., 200° C. or higher), optionally in the presence of a catalyst such as H2, NO, PF3, PH3, NH3 and / or I2, as described, for example, in U.S. Pat. No. 4,056,386. Iron can be reacted with hydrochloric acid (preferably in excess) to obtain FeCl2. FeCl2 can be reacted with hydrochloric acid and sodium chlorate (preferably in a slight deficiency) to obtain FeCl3. FeCl2 can be reacted with hydrochloric acid and oxidized, for example, using hydrogen peroxide, to form FeCl3. This reaction can be used to oxidize the FeCl2 remaining from the reaction with hydrochloric acid and sodium chlorate to achieve a more complete conversion of FeCl2 to FeCl3. Chlorine (Cl2; gas) can also be used as an oxidizing agent.

[0136] Carbonyl iron can be produced, for example, from iron pentacarbonyl, which can be prepared, for example, by applying carbon monoxide to hot iron (for example, at a high temperature of about 200° C.), preferably under high pressure (for example, at a high pressure of 15 to 20 MPa). Such a method for the preparation of carbonyl iron via iron pentacarbonyl is described, for example, in French patent application No. 607.134 of Badische Anilin- & Soda-Fabrik, published on June 26, 1926.

[0137] Methods for preparing the iron preparations described herein by recrystallization of the iron salt preparation from its aqueous solution are known in the art. For this purpose, an aqueous solution of a water-soluble iron salt preparation is provided, an iron salt (e.g., ferric nitrate) is recrystallized from the solution (e.g., by lowering the temperature of the solution), and the iron salt crystals are separated from the liquid, dissolved to form its aqueous solution and again subjected to recrystallization and separation. The steps of dissolution, recrystallization and separation can be repeated once or several more times to increase the purity of the iron salt preparation and in particular to reduce the amount of non-ferrous metal impurities. According to a particular example, ferric nitrate is recrystallized from its aqueous solution containing nitric acid. Specifically, ferric nitrate is dissolved in a 55-65% aqueous nitric acid solution at 50-60°C. When the solution is cooled to a temperature of about 15°C or less, a precipitate of crystalline ferric nitrate is formed and can be separated from the liquid. The steps of dissolution, recrystallization and separation can be repeated once or several more times.

[0138] Methods for preparing the iron preparations described herein by extracting aqueous iron salt solutions with organic solvents are known in the art. For this purpose, an aqueous solution of ferric chloride can be treated with an organic solvent to selectively dissolve the ferric chloride in the organic solvent (extraction), and then the selectively dissolved ferric chloride can be recovered by removing the organic solvent from the ferric chloride. Examples of organic solvents include alcohols having 4-20 carbon atoms, especially alcohols having 6-10 carbon atoms, e.g. n-octanol, and organic solutions of amine salts such as tri-n-laurylamine hydrochloride in toluene. The presence of hydrochloric acid in the aqueous ferric chloride solution can improve the extraction efficiency. It is advantageous to increase the concentration of ferric chloride in the starting aqueous solution by partial evaporation, especially to a concentration in the range of 280-850 g / l ferric chloride, before adding the organic solvent. The purification cycles of evaporation and solvent extraction can be repeated until a ferric chloride preparation of the desired purity is obtained. If the ferrous chloride is first converted to ferric chloride by oxidation with chlorine, the aqueous solution of ferrous chloride can also be purified. Specific methods for the extraction of iron salts with organic solvents are described, for example, in Canadian Patent Application Publication No. 2318823A1 and Muller et al. ("Liquid-liquid extraction of ferric chloride by tri-n-laurylamine hydrochloride", EUR2245.e, Euratom report, Transplutonium Elements Program, Euratom Contract No. 003-61-2 TPUB, Presses Academiques Europeennes, Brussels, 1965).

[0139] Electrolysis of aqueous iron salt solutions, in which iron is precipitated at the anode, is known in the art. See, for example, Cain et al. ("Preparation of pure iron and iron-carbon alloy" in Bulletin of the Bureau of Standards, Vol. 13, 1916) and Mostad et al. (Hydrometallurgy, 2008, 90, 213-220). Iron solutions suitable for electrolysis include iron chloride solutions, iron sulfate solutions, and solutions containing both iron chloride and iron sulfate. The solutions are typically neutral or acidic.

[0140] The iron preparations described herein can further be obtained by contacting an aqueous iron salt solution with a base to form a precipitate of iron hydroxide and separating the precipitate from the liquid by filtration or centrifugation. Suitable bases for precipitating iron hydroxide include sodium hydroxide or sodium carbonate. Alternatively, sodium bicarbonate can be used. Methods for separating such precipitates from the remaining solution by filtration or centrifugation are known in the art.

[0141] Iron preparations low in non-ferrous metal impurities, such as the iron preparations used in the process of the invention, can also be prepared by distillation of a mixture containing ferric chloride and non-volatile impurities. In the case of distillation, the mixture is subjected to a temperature and pressure selected such that at the selected pressure and temperature the mixture is near its boiling point. Under such conditions the mixture separates into a vapor phase and a slurry of non-volatile impurities in liquid ferric chloride. The vapor is substantially pure ferric chloride, which can be recovered by separating the vapor from the slurry. According to a particular embodiment, a temperature near the boiling point of the mixture means a temperature within 10°C of said boiling point, preferably said boiling point. The distillation can be carried out, for example, at a temperature in the range of 300°C to 700°C and a pressure in the range of 0.1 to 5.1 MPa, preferably in the range of 0.2 to 0.4 MPa, and at the selected pressure and temperature the mixture is approximately at its boiling point.

[0142] During distillation, settling of non-volatile solids in the slurry can be prevented by mechanically stirring the slurry (e.g., with a paddle stirrer, etc.) or, preferably, by bubbling a gas (e.g., nitrogen, helium, chlorine, or mixtures thereof) through the slurry.

[0143] After separation of the ferric chloride vapor, the remaining slurry can be recycled by heating the slurry to evaporate the ferric chloride, separating and cooling the ferric chloride-containing vapor and reintroducing it into the distillation process. Preferably, recycling of the slurry is carried out such that the amount of solids present in the slurry during distillation is less than about 20% by weight, particularly less than about 12% by weight.

[0144] The mixture containing ferric chloride and non-volatile impurities to be fed to the distillation process can be obtained, for example, by chlorinating an iron-containing ore (e.g., a titaniferous ore such as ilmenite) to produce a gaseous mixture containing ferric chloride and non-volatile impurities, and cooling the gas to precipitate a solid mixture of ferric chloride and non-volatile impurities. Said solid mixture can then be fed to the distillation process. Before separating the solid mixture of ferric chloride and non-volatile impurities from the gaseous mixture, the gaseous mixture can optionally be exposed to a temperature above the dew point of ferric chloride to remove the non-volatile impurities that are no longer gaseous at this temperature. Such a pre-purified gaseous mixture can then be cooled to precipitate a solid mixture of ferric chloride and non-volatile impurities that can be fed to the distillation process. See, for example, U.S. Pat. No. 3,906,077, which is incorporated by reference in its entirety.

[0145] To further increase the purity of the iron preparation, different methods for preparing and purifying the iron preparation can be combined. For example, iron prepared by electrolysis of an aqueous iron salt solution can be converted into a water-soluble iron salt, which can then be purified by (1) dissolution to form an aqueous iron salt; (2) recrystallization of iron salts from aqueous solutions, and (3) Separation of the recrystallized iron salt from the remaining solution The treatment can be subjected to one or more cycles of

[0146] [Complex] For iron ions to be suitable for parenteral administration, they must be complexed with a ligand so that the amount of free iron ions is low and the iron is released in a controlled manner after administration. Advantageously, the total amount of free iron contained in the iron complex compound before administration is 0.01% w / v or less, preferably less than 0.003% w / v (for iron complex compounds present as 100 mg / mL solutions). In other words, the total amount of free iron relative to the total iron content is 0.1% or less, preferably less than 0.03% free iron by weight of the total iron content (for iron complex compounds present as 100 mg / mL solutions). This requires that the iron complex compound has sufficient physical stability to be processed into a final formulation and stored until it is used.

[0147] [Iron-sugar complex] According to one group of embodiments, the iron complex compound is an iron-sugar complex compound, i.e., the ligand in the iron complex compound is a sugar.

[0148] The iron-sugar complex compounds of the present invention include complexes with the sugar ligands disclosed herein, such as iron carboxymaltose, iron polyglucose sorbitol carboxymethyl ether complex, iron mannitol complex, iron dextran, iron hydrogenated dextran, iron oxidized dextran, iron carboxyalkylated reduced oligo- and polysaccharides, iron sucrose, iron gluconate, iron dextrin, iron hydrogenated dextrin, iron oxidized dextrin, hydrogenated iron oligosaccharides such as iron oligomaltose, hydrogenated iron oligomaltose, hydrogenated iron oligoisomaltose, iron hydroxyethyl starch, iron sorbitol, iron dextran glucoheptonate (e.g., gleptoferron), and mixtures of two or more thereof. According to a particular embodiment, the iron sugar complex compound of the present invention is selected from iron carboxymaltose, iron polyglucose sorbitol carboxymethyl ether complex, iron mannitol complex, iron dextran, iron hydrogenated dextran, iron sucrose, iron gluconate, iron dextrin, hydrogenated oligoisomaltose, and mixtures of two or more thereof. In a more preferred embodiment, the iron sugar complex is hydrogenated oligoisomaltose (iron oligoisomaltoside).

[0149] The amount of iron in the iron-sugar complex compounds of the present invention, determined on dry matter, is typically in the range of from 10 to 50%, preferably from 15 to 35%, most preferably from 20 to 30%, for example from 20 to 25%, iron by weight of the sugar complex.

[0150] Thus, the weight ratio of elemental iron to sugar in the complex will typically be from 10:90 to 50:50, preferably from 15:85 to 45:55, most preferably from 20:80 to 40:60, for example about 70:30.

[0151] The "apparent" peak molecular weight (M p ) is typically in the range of 800 to 800,000 Da, for example 10,000 to 500,000 Da, or 20,000 to 400,000 Da, or 50,000 to 300,000 Da, in particular 90,000 to 200,000 Da. pcan be quantified, for example, by gel permeation chromatography using dextran standards. See, for example, the method described in Jahn et al., Eur J Pharm Biopharm 2011, 78, 480-491. For the oligoisomaltose(toside)iron complexes disclosed herein, the "apparent" peak molecular weight (M p ) is typically in the range of 120,000 to 190,000 Da, in particular 125,000 to 185,000 Da or 130,000 to 180,000 Da. p ) has proven to be advantageous, particularly for the ferric octasaccharide disclosed herein. Preferably, the "apparent" peak molecular weight (M p ) is in the range of 145,000 to 155,000 Da, particularly for the ferric octasaccharide disclosed herein. The ferric oligoisomaltose(tosido)s of the present invention preferably have a relatively narrow molecular weight distribution with a polydispersity (Mw / Mn) in the range of 1.0 to 1.5, preferably 1.05 to 1.4, more preferably 1.1 to 1.3, for example about 1.2.

[0152] In some embodiments, the iron-sugar complex of the present invention may include a stabilizer such as an organic acid. Preferably, the organic acid is an organic hydroxy acid. Suitable examples of organic hydroxy acids are gluconic acid and citric acid. Citric acid is a convenient example. When present, the amount of citric acid is typically in the range of 3 to 20% by weight of the total amount of elemental iron.

[0153] Thus, iron sugar complexes particularly suitable for use in the present invention are ferric oligoisomaltose(tosides), such as ferric isomaltoside 1000 (INN name: ferric delisomaltose) or ferric octasaccharide, as disclosed herein. The term "ferric oligoisomaltoside" as used herein refers to a colloidal complex comprising iron, e.g., ferric oxide hydroxide, and an oligoisomaltoside in a matrix-like structure.

[0154] Iron oligoisomaltoside is a preferred iron sugar complex for use in the present invention. In a preferred embodiment, the iron sugar complex for use in the present invention comprises an iron oxide hydroxide stably bound to an octasaccharide. In a preferred embodiment, the iron sugar complex is a ferric octasaccharide.

[0155] Other examples of iron oligoisomaltosides are commercially available in many countries under the trade names Monofer®, Monoferric® or Diafer®.

[0156] It has been found that the iron oligoisomaltoside complexes of the invention have properties that have proven to be advantageous when it comes to their medical use: in particular, it has been found that in a 100 mg / mL solution of the iron oligoisomaltoside complex, the total amount of free iron is less than 0.01% w / v, particularly preferably less than 0.003% w / v.

[0157] Moreover, it has been observed that the strength of the iron oligoisomaltoside complexes of the invention is high enough to release iron in an appropriate form under physiological conditions in vivo when administered to a human or non-human subject. There are in vitro tests that allow a rapid assessment of strength. In one test, the complexes are subjected to hydrochloric acid hydrolysis under defined conditions (0.24 M HCl; 0.9% NaCl). The assay then determines the time that elapses until half of the iron-sugar complex in solution dissociates into its constituent parts (iron and sugar). This can be done by measuring the optical absorbance at 287.3 nm. The duration (T1 / 2) measured in vitro is a surrogate measure of the relative rate of dissociation of the iron-sugar complex after administration in vivo, i.e., a measure of the strength of the complex. In this test, the iron oligoisomaltoside complexes of the invention were found to have a half-life (T1 / 2) of at least 20 hours, preferably at least 25 hours, more preferably at least 30 hours. Advantageously, complexes suitable for use in the invention have such a half-life. This ensures that the toxicity of free iron is reduced while the iron from the iron complex compound is absorbed. On the other hand, a half-life (T1 / 2) of 60 hours or less, preferably 50 hours or less, more preferably 40 hours or less also provides a great advantage in terms of allowing adequate intake of iron into the body. A half-life in the range of 25 to 35 hours is particularly preferred.

[0158] Another specific iron sugar complex for use in the present invention is ferric bepectate (FBP). Ferric bepectate is disclosed, for example, in WO 2012 / 175608 A1, the entire contents of which are incorporated by reference. Iron complexes with dextran glucoheptonate are further specific iron sugar complexes for use in the present invention. These are also known as gleptoferrons and are commercially available iron sugar complexes for pigs. Ferric dextran glucoheptonates, such as gleptoferrons, are disclosed, for example, in U.S. Pat. No. 3,639,588.

[0159] According to another group of embodiments, the iron complex compound is a polymeric ligand-substituted oxo-hydroxy iron complex compound. The polymeric ligand-substituted oxo-hydroxy iron complex compound is a compound that oxidizes iron ions (e.g., Fe 3+), ligands, and oxo and / or hydroxyl groups. The iron ions, oxo and / or hydroxyl groups form polyoxo-hydroxyiron particles. The ligands are incorporated therein by substituting some of the oxo or hydroxyl groups initially present. This substitution is generally non-stoichiometric and occurs through formal bonding, resulting in distinct changes in the chemistry, crystallinity, and material properties of the oxo-hydroxyiron. Polymeric ligand-substituted oxo-hydroxyiron complex compounds are described, for example, in WO 2008 / 096130 A1.

[0160] The average molar ratio of ligand to iron is typically in the range of 10:1 to 1:10, such as 5:1 to 1:5, 4.1 to 1:4, 3.1 to 1:3, 2:1 to 1:2, or about 1:1.

[0161] [Preparation of iron complex compounds] The iron complex compounds of the present invention can be prepared by contacting an iron preparation with a ligand in the presence of water. An iron preparation containing iron in the form of iron hydroxide and / or iron oxide hydroxide can be used directly in this process. For example, a precipitate of iron hydroxide (e.g., ferric hydroxide) and / or iron oxide hydroxide in an aqueous solution is contacted with a ligand (e.g., a sugar preparation) followed by heating and increasing the pH to form an iron complex compound (e.g., an iron complex compound containing a FeO(OH) core). Alternatively, the iron hydroxide and / or iron oxide hydroxide of the iron preparation are converted to a water-soluble iron salt as described herein by contacting the iron preparation with an acid. Conveniently, this conversion is carried out in an aqueous solution containing the reactants (iron hydroxide and / or iron oxide hydroxide and acid). The choice of acid depends on the iron salt to be produced. For example, iron chloride can be prepared by reacting the iron hydroxide and / or iron oxide hydroxide of the iron preparation with hydrochloric acid. Advantageously, in step (ii) of the method of the invention for preparing an iron complex compound, the reagents used in addition to the iron preparation are substantially free of non-ferrous impurities such as arsenic, chromium, lead, mercury, cadmium and / or aluminium.

[0162] Therefore, the iron-sugar complex compound of the present invention has (1) providing an aqueous solution comprising a sugar and an iron preparation described herein comprising a water-soluble iron salt (e.g., ferric chloride); (2) adding a base to the aqueous solution to form iron hydroxide; and (3) Next, the aqueous solution is heated to form an iron-sugar complex compound. It can be prepared by

[0163] Preferably, the pH of the aqueous solution in step (1) is acidic to prevent precipitation of iron hydroxide, for example the pH of the solution is below 2. The addition of base in step (2) is preferably carried out slowly or gradually to raise the pH, for example to a pH of 5 or above, for example to pH 11, 12, 13 or 14. Such a gradual increase can be achieved by first adding a weak base (e.g. an alkali metal or alkaline earth metal carbonate, for example sodium carbonate, potassium carbonate, sodium or potassium bicarbonate, or ammonium carbonate or bicarbonate, or ammonia) to increase the pH, for example to a pH of 2-4, for example to 2-3, and then further increasing the pH by adding a strong base (e.g. an alkali metal or alkaline earth metal hydroxide, such as sodium hydroxide, potassium hydroxide, calcium hydroxide or magnesium hydroxide).

[0164] Alternatively, the iron-sugar complex compound of the present invention is (1) providing an aqueous solution comprising a sugar and an iron preparation as described herein, the iron preparation comprising iron hydroxide, iron oxide hydroxide, or a mixture thereof; and (2) Next, the aqueous solution is heated to form an iron-sugar complex compound. It can be prepared by

[0165] Heating the aqueous solution in the last step of the above two methods for preparing the iron-sugar complex compound of the present invention promotes the formation of the iron-sugar complex compound. For example, the aqueous solution can be heated to a temperature ranging from 15°C to boiling. Preferably, the temperature is gradually increased, for example, in the first step the aqueous solution is heated to a temperature of 15 to 70°C and then gradually further heated to boiling. To terminate the reaction, the pH can be lowered, for example to pH 5-7, by adding an acid, for example HCl or aqueous hydrochloric acid. In one embodiment, the pH is lowered when the solution is heated to about 50°C before further heating.

[0166] After heating, the product can be further processed by filtration and its pH can be adjusted to a neutral or slightly acidic pH (e.g., pH 5 to 7) by adding a base or acid such as those mentioned above. Further optional steps include purification, particularly removal of salts, which can be achieved by ultrafiltration or dialysis, and sterilization, which can be achieved by sterile filtration and / or heat treatment (e.g., at temperatures above 121° C.). The purified solution can be used directly for the preparation of a pharmaceutical composition. Alternatively, a solid iron-sugar complex can be obtained by precipitation, for example by addition of an alcohol such as ethanol, or by drying, for example by spray drying.

[0167] The iron-sugar complex compound can be stabilized by mixing it with an organic hydroxyl acid or its salt, such as citric acid, citrate gluconic acid or gluconate.

[0168] Thus, a typical process for producing iron oligoisomaltose (tosido)s includes the following steps: (a) hydrolyzing dextran to obtain a hydrolysate; (b) fractionating the hydrolysate to obtain oligoisomaltose; and (c) hydrogenating oligoisomaltose to obtain oligoisomaltoside (d) Iron complex formation process and if the process is for producing iron oligoisomaltoside, a hydrogenation step is included.

[0169] Further optional steps are as follows: Purification, e.g., diafiltration, to reduce the levels of mono- and disaccharides in the oligoisomaltosides; Purification, e.g. by ion exchange, to obtain purified oligoisomaltosides; Heating the complex; Filtration of the heated complex; Membrane filtration to obtain the purified complex; Addition of organic acids such as citrate to obtain stabilized complexes; Spray drying to obtain the complex as a solid, e.g., a powder.

[0170] For example, iron oligoisomaltose(toside), such as the iron octasaccharide of the present invention, can be prepared by contacting the disclosed oligoisomaltose(toside) with ferric chloride in water. Na2CO3 is then added, followed by NaOH, to reach a pH of about 10.5. Heating gives a black or dark brown colloidal solution, which can be neutralized using HCl and filtered. Unbound octasaccharide residues, free iron, and inorganic salts can be removed by membrane filtration. Citric acid monohydrate may be added to further stabilize the complex. Adjustment to a neutral or slightly acidic pH gives a solution, which can then be converted into a solid form, such as a powder. For this purpose, the solution can be spray-dried to give a black or dark brown powder.

[0171] Iron oligoisomaltoside can be obtained, for example, as described in WO 2010 / 108493 A1 and WO 2019 / 048674 A1, the entire contents of which are incorporated by reference.

[0172] Ferric bepectate and its preparation are disclosed, for example, in WO 2012 / 175608 A1, the entire contents of which are incorporated by reference. Briefly, hydroxyethyl starch is dissolved in water. The pH value is then adjusted to a value between 8.0 and 10.0. A cyanide compound is then added to the hydroxyethyl starch solution. The solution is then heated to a temperature between 80 and 99°C and maintained at this temperature for a first period of time. Finally, the pH value is adjusted to a value between 2.0 and 4.0, the temperature of the solution is brought to a value between 50 and 90°C and maintained at this temperature for a second period of time. The preparation method of this heptonate modified hydroxyethyl starch, HES70 / 0.5, is described in Example 1 of WO 2012 / 175608 A1, the entire contents of which are incorporated by reference, and the formation of the iron complex is described in Example 2.

[0173] The polymeric ligand-substituted oxo-hydroxy iron complex compounds of the present invention can be prepared by contacting an iron preparation disclosed herein with a ligand in an aqueous solution at a first pH (A), and then changing the pH (A) to a second pH (B) to produce a solid precipitate of the polymeric ligand-substituted oxo-hydroxy iron complex compound. The solid precipitate can have a particulate, colloidal, or subcolloidal (nanoparticle) structure.

[0174] The pH(A) is different from the pH(B). Preferably, the pH(A) is more acidic than the pH(B). For example, the pH(A) is equal to or less than pH2 and the pH(B) is greater than pH2. Starting from a pH at which the oxo-hydroxy polymerization is initiated, the pH is preferably further increased to complete the reaction and promote precipitation of the polymeric ligand-substituted oxo-hydroxy iron complex compound formed. During the pH change, further ligands and / or additives can be added. The pH change is preferably carried out in a gradual or stepwise manner, for example over about 24 hours, or over about 1 hour, in particular over 20 minutes. The pH change may be made by the addition of an acid or a base. For example, the pH can be increased by adding sodium hydroxide, potassium hydroxide, or sodium bicarbonate.

[0175] Polymeric ligand-substituted oxo-hydroxy iron complex compounds are typically produced in aqueous solutions with iron ion and ligand concentrations of 1 μM or more, particularly 1 mM or more. The ratio of iron ion to ligand is selected such that the relative amount of iron ion is not too high so that the rate of oxo-hydroxy polymerization is too fast to prevent efficient ligand incorporation, and the relative amount of ligand is not too high to prevent iron oxo-hydroxy polymerization. For example, the iron concentration is in the range of 1 mM to 300 mM, such as 20 mM to 200 mM, particularly about 40 mM.

[0176] The ligands used in the formation of the polymeric ligand-substituted oxo-hydroxy iron complex compounds may have some buffering capacity that helps stabilize the pH range during complex formation. Buffering can also be achieved by adding an inorganic or organic buffer that does not participate in formal binding with the iron ion to the aqueous solution containing the iron preparation and ligand. Typically, the concentration of such buffers, if present, is less than 500 mM or less than 200 mM, especially less than 100 mM.

[0177] Formation of the polymeric ligand substituted oxo-hydroxy iron complex compound typically occurs at a temperature in the range of from 20°C to 120°C, for example from 20°C to 100°C, especially from 20°C to 30°C.

[0178] Optionally, the ionic strength in the aqueous solution comprising the iron preparation and the ligand can be increased by adding further electrolytes such as potassium chloride or sodium chloride in an amount of, for example, up to 10% by weight, such as up to 12% by weight, in particular up to 1% by weight.

[0179] The solid precipitate of the polymeric ligand-substituted oxo-hydroxy iron complex compound can be isolated, optionally dried, and further processed, for example by grinding, prior to further use or formulation.

[0180] Pharmaceutical Compositions The present invention further relates to a pharmaceutical composition comprising the iron complex compound of the present invention and a pharma- ceutically acceptable carrier.

[0181] Preferred are pharmaceutical compositions for parenteral use. These can be ready-to-use fluids (fluids for injection or infusion); fluids to be diluted before use; or solids for reconstitution. Ideally, such fluids are isotonic, sterile, pyrogen-free, and maintain adequate physical and chemical stability over the intended storage period. However, it is not always possible to meet all of these objectives, and often it is necessary to balance opposing forces in order to find the "sweet spot" of a pharmaceutical composition suitable for its intended purpose.

[0182] Particularly preferred are ready-to-use injectable compositions.

[0183] Thus, the pharmaceutical compositions of the present invention include flowable compositions suitable for injection or infusion, comprising an iron complex compound, water for injection, and optionally further convenient additives. Fluids include liquids that are preferably present as a solution (i.e., fluids, particularly liquids in which the iron complex compound is dissolved). These fluids may have the concentration of the iron complex compound desired to be administered. Alternatively, the iron complex compound may be concentrated; such concentrates must be diluted with a suitable fluid before administration. The pharmaceutical compositions of the present invention also include solids, such as powders, for reconstitution with a suitable fluid before administration. For example, the pharmaceutical compositions may be stored in a spray-dried or lyophilized form, and then reconstituted as an aqueous composition, preferably a solution, typically suitable for parenteral administration, before administration to a subject. Such compositions may be reconstituted with sterile water for injection (WFI). A bacteriostatic agent, such as benzyl alcohol or phenol, may be included.

[0184] According to a preferred embodiment of the present invention, the pharmaceutical composition is suitable for subcutaneous administration. Thus, particularly preferred are ready-to-use injectable pharmaceutical compositions for subcutaneous use. Usually, subcutaneous administration is limited by the total volume of the fluid to be injected. When the amount of iron sugar compound to be administered to the subject is relatively large (e.g., 10-30 mg iron / kg body weight in the form of iron complex compound), it may be necessary to formulate the fluid with a relatively high concentration of iron complex compound to reach an acceptable injection volume. In general, it is necessary to include as much iron as possible in a given volume of fluid to minimize the injection volume. However, a relatively high concentration of iron complex compound may result in a viscous liquid that is difficult and / or painful to inject. Also, a lower iron concentration may be required due to pH and osmolality considerations. Furthermore, a relatively high concentration of iron complex compound may reduce the physical stability of the iron complex compound, thus resulting in a shorter shelf life.

[0185] Conveniently, the pharmaceutical composition of the present invention comprises 1 to 25%, preferably 2.5 to 20%, most preferably 2.5 to 7.5%, or 7.5 to 12.5%, or 15% to 20%, e.g., about 5% or about 10% or about 20% (w / v) elemental iron. In other words, the concentration of the iron complex compound in the flowable pharmaceutical composition is 25 to 300 mg / mL, preferably 50 to 200 mg / mL, most preferably 75 to 150 mg / mL, e.g., about 100 mg / mL elemental iron.

[0186] Considering parenteral administration, particularly subcutaneous administration, the pH of the flowable pharmaceutical composition is conveniently in the range of 5.8 to 7.0, preferably 5.9 to 6.8; most preferably 5.9 to 6.6, e.g. 6.0 to 6.4. In general, it is preferred to select a pH close to the upper end of these ranges, i.e., neutral pH. Injectable and injectable compositions should therefore be suitably buffered, if necessary. In this context, the sterile aqueous media that can be used will be known to those skilled in the art in view of the present disclosure. For example, a single dose can be prepared with a volume of isotonic NaCl solution and sterile water prior to injection. For subcutaneous injection, the composition is typically administered without prior dilution (unless the size of the animal requires a dose that is too low to be injected). A typical subcutaneous injection volume is 0.5 to 5 mL.

[0187] The turbidity of the flowable pharmaceutical composition is advantageously less than 2.0 NTU, preferably less than 1.5 NTU, most preferably less than 1.0 NTU, such as less than 0.5 NTU.

[0188] Flow properties such as syringeability and injectability are properties to be evaluated and controlled. Syringability describes the ability of a composition to easily pass through a hypodermic needle when transferred from a vial prior to injection. This includes properties such as ease of withdrawal, tendency to clog or foam, and accuracy of dose measurement. Increased viscosity and density decrease the syringeability of a composition.

[0189] Injectability refers to the performance of a composition during injection and includes factors such as the pressure or force required for injection, uniformity of flow, aspiration, and lack of clogging. The needleability and injectability of a composition are closely related to the viscosity of the composition. The mere expulsion of a composition into the air, if done very slowly with intermittent pressure on the plunger, can provide certain information about the composition. Most methods used for injectability are qualitative in nature. Force monitoring devices such as Instron can be used to determine the expulsion and injection pressures and the test results can be recorded on an XY recorder. Another instrument to evaluate injectability measures the time required to smoothly inject a solution or suspension into meat under a specified pressure through a needle from a syringe. Injecting a test solution through glass and plastic syringes of various sizes, using needles of various gauges, yields regression equations for a given syringe type and diameter. These equations allow the calculation of expected injection times for a given vehicle with a given needle system and a given viscosity.

[0190] To provide a composition with suitable syringeability, the fluid pharmaceutical composition of the present invention advantageously has a viscosity of 60 cP or less. In another embodiment, the composition has a viscosity of 50 cP or less, or 40 cP or less, or 30 cP or less, or 20 cP or less, or 40 cP or less, or 15 cP or less. In some embodiments, the composition has a viscosity at 25° C. of between 1 cP and 50 cP, between 1 cP and 40 cP, between 1 cP and 30 cP, between 1 cP and 20 cP, between 1 cP and 15 cP, or between 1 cP and 10 cP. In some embodiments, the composition has a viscosity of about 50 cP, about 45 cP, about 40 cP, about 35 cP, about 30 cP, about 25 cP, about 20 cP, about 15 cP, or about 10 cP, or about 5 cP. In some embodiments, the composition has a viscosity between 10 cP and 50 cP, between 10 cP and 30 cP, between 10 cP and 20 cP, or between 5 cP and 15 cP.

[0191] "Viscosity" as used herein can be "kinematic viscosity" or "absolute viscosity". "Kinematic viscosity" is a measure of the resistive flow of a fluid under the influence of gravity. When equal volumes of two fluids are placed in the same capillary viscometer and allowed to flow by gravity, the more viscous fluid will take longer to flow through the capillary than the less viscous fluid. If one fluid takes 200 seconds to complete its flow and another takes 400 seconds, then on the kinematic viscosity scale the second fluid is twice as viscous as the first. "Absolute viscosity", also called dynamic viscosity or simple viscosity, is the product of kinematic viscosity and fluid density: absolute viscosity = kinematic viscosity × density. Kinematic viscosity has dimensions L 2 / T where L is length and T is time. Kinematic viscosity is generally expressed in centistokes (cSt). The SI unit of kinematic viscosity is mm 2 / s , or 1 cSt. Absolute viscosity is expressed in units of centipoise (cP). The SI unit of absolute viscosity is millipascal-second (mPa-s), where 1 cP = 1 mPa-s.

[0192] For storage reasons, the flowable pharmaceutical composition has a shelf life of at least 1 year at 25°C, preferably at least 2 years at 25°C, and more preferably at least 3 years at 25°C.

[0193] [Combination therapy] Further described herein is a combination of an iron complex compound with one or more additional drugs. According to certain embodiments, the additional drugs are selected from the group consisting of: (1) Erythropoiesis stimulating agents (ESAs), such as erythropoietin (Epo), epoetin alfa (Procrit / Epogen), epoetin beta (NeoRecormon), darbepoetin alfa (Aranesp), methoxypolyethylene glycol-epoetin beta (Mircera), or those disclosed in U.S. Patent Application Publication No. 20210032305 A, all of which are incorporated by reference; (2) Hepcidin modulators such as hepcidin agonists or hepcidin antagonists (3) Antiparasitic drugs, including antiparasiticides, ectoparasiticides, and endoparasiticides; (4) chemotherapy drugs; (5) Antibiotics; (6) Antiviral drugs; and (7) Vaccines.

[0194] Those suitable for use in the treatment of iron deficiency according to the invention represent a particular embodiment of this aspect of the invention. For example, in cats with CKD, erythropoiesis stimulating agents are indicated and would be administered in addition to the iron complex compounds according to the invention when treatment of iron deficiency, particularly iron deficiency anemia, is required.

[0195] [Dosage regimen] A method of treating iron deficiency in a subject according to the present invention comprises administering to a subject in need of such treatment a therapeutically effective amount of an iron complex compound. Thus, the method of the present invention may, and in a preferred embodiment does, comprise determining whether the subject is iron deficient prior to said administration of an iron complex compound, and administering said iron complex compound if said subject is iron deficient.

[0196] Depending on the body weight of the animal to be treated, some variation in dosage will necessarily occur. In any event, the person responsible for administration will determine the appropriate dosage. A typical treatment regimen for the iron complex compound will consist of a dosage of 5 to 100 mg, for example 10 to 60 mg, particularly 15 to 25 mg, for example about 20 mg, of elemental iron per kg body weight. Alternatively, the effective amount of the iron complex compound is an amount of up to 50 mg iron / kg body weight, particularly up to 30 mg iron / kg body weight, or preferably up to 20 mg iron / kg body weight. Thus, a typical dosage of the iron complex compound may be 10 to 2800 mg elemental iron for subjects such as dogs with a body weight ranging from 0.5 to 140 kg.

[0197] The cumulative iron requirement can be determined using the Ganzoni formula, and according to one embodiment, the calculated dose is administered. Thus, in some embodiments, the effective therapeutic amount of the iron complex compound is equal to the cumulative iron requirement. Such cumulative iron requirement may be lower or higher than the typical dose.

[0198] Generally, it is preferred that the dose is administered in a single setting (visit). Such a (single) dose may be provided as a single (1) administration (e.g., injection) or in two, three or more administrations (e.g., injections) depending on the administration volume. Generally, when the administration volume is greater than 5 mL, 7.5 mL or 10 mL, it is preferred to split the dose into two, three or more administrations to reduce the volume administered at each administration site. This is especially true for subcutaneous administration. The importance of splitting the dose and reducing the volume administered will vary depending on the size of the subject and the laxity of the subject's skin. A person skilled in the art will know how to determine the volume to be administered.

[0199] In another specific embodiment, the treatment methods of the invention include administering two, or three, or four, or five or more doses over a period of time to ensure effective treatment of ID or IDA, for example, in situations where a single dose is insufficient or where clinical signs of ID or IDA reappear after previously disappearing, and / or where ID or IDA is newly diagnosed in the same subject.

[0200] In a further particular embodiment, the therapeutic method of the invention involves administering several repeated doses over time to manage ID or IDA in subjects with chronic blood loss caused by an underlying disease, such as subjects with CKD or subjects with IBD, such subjects potentially needing iron on an ongoing basis (as maintenance therapy) and therefore needing to repeat the treatment periodically on an ongoing basis.

[0201] In the case of repeated administration, a first dose of up to 50 mg iron / kg body weight, in particular up to 30 mg iron / kg body weight, or preferably up to 20 mg iron / kg body weight, is followed by a second dose of up to 50 mg iron / kg body weight, in particular up to 30 mg iron / kg body weight, or preferably up to 20 mg iron / kg body weight. The two successive doses can be administered within one month, within two weeks, or preferably within one week. Preferably, they are administered within one week. The further dose is up to 50 mg iron / kg body weight, in particular up to 30 mg iron / kg body weight, or preferably up to 20 mg iron / kg body weight. This further, for example a third dose, can be administered within the same time frame, i.e. within one month, two weeks, or preferably within one week. These multiple doses are preferably administered at least two days apart, in particular three days apart. For example, if three doses are to be administered within one week, it is preferred that these doses are administered on the 1st, 4th, and 7th days.

[0202] According to the present invention, the iron complex compound can be administered parenterally, for example, by intramuscular injection, intravenous (IV) bolus injection, or IV infusion. However, according to a preferred embodiment of the present invention, the parenteral administration of the iron complex compound is subcutaneous administration. For example, a convenient site for subcutaneous administration is one that is bounded by relatively loose skin, such as the area on the lateral side of the dorsal surface behind the shoulder blades on the ribs of a companion animal, such as a dog. Alternatively, the dorsal paralumbar area can be used for injection. Other typical areas for subcutaneous injection are known to those skilled in the art.

[0203] Administration "in combination with" one or more additional therapeutic agents includes simultaneous (concurrent) and sequential or sequential administration in any order. The term "concurrent" is used herein to refer to the administration of two or more therapeutic agents where at least a portion of the administration overlaps in time or where the administration of one therapeutic agent falls within a short period of time compared to the administration of the other therapeutic agent. For example, the two or more therapeutic agents are administered at a time interval of about a certain number of minutes or less. The term "sequential" is used herein to refer to the administration of two or more therapeutic agents where the administration of one or more therapeutic agents continues after the administration of one or more other agents is stopped or where the administration of one or more therapeutic agents begins before the administration of one or more other agents. For example, the administration of two or more therapeutic agents is administered at a time interval of more than about a certain number of minutes. As used herein, "in combination with" refers to the administration of one therapeutic modality in addition to another therapeutic modality. Thus, "in combination with" refers to the administration of one therapeutic modality before, during, or after the administration of another therapeutic modality to an animal.

[0204] [Ferric octasaccharide] In certain embodiments, the present invention is particularly directed to ferric octasaccharide complexes and pharmaceutical compositions comprising the ferric octasaccharide complexes. The ferric octasaccharide complexes are particularly useful in the methods of treatment described herein. All references below to the ferric octasaccharides of the present invention apply equally to the use of the ferric octasaccharides in the methods of treatment disclosed herein.

[0205] The ferric octasaccharide comprises iron complexed with an octasaccharide. Preferably, the ferric octasaccharide comprises an iron oxide hydroxide stably associated with the octasaccharide. In some embodiments, the ferric octasaccharide comprises a stabilizer such as an organic acid. Preferably, the organic acid is an organic hydroxy acid. Suitable examples of organic hydroxy acids are gluconic acid and citric acid. Citric acid is a convenient example. When citric acid is present, the amount is typically in the range of 3 to 20% by weight of the total amount of elemental iron.

[0206] In some embodiments, the ferric octasaccharide comprises a salt such as a metal chloride. The metal chloride can be sodium chloride or potassium chloride. Preferably, the metal chloride is sodium chloride. When sodium chloride is present, the amount is typically in the range of 3 to 110% by weight of the total amount of elemental iron.

[0207] In some embodiments, the ferric octasaccharide comprises water, the amount of water, if present, typically ranging from 3 to 25% by weight of the total amount of elemental iron.

[0208] In certain embodiments, the ferric octasaccharide comprises a stabilizer, a salt, and water. In a preferred embodiment, the ferric octasaccharide comprises citric acid, sodium chloride, and water.

[0209] In one aspect of the invention, a compound of formula: {FeOOH,(octasaccharide) Q} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085. A ferric octasaccharide is provided having the formula:

[0210] In a preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; and R has a molecular weight of from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031.

[0211] In another preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH,(octasaccharide)Q ,(C6H8O7) R} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; and The metal chloride comprises sodium chloride or potassium chloride, preferably sodium chloride.

[0212] In another preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion such as a sodium ion or a potassium ion, preferably a sodium ion.

[0213] In another preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, Q is 0.08 to 0.09, preferably about 0.085; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a sodium ion.

[0214] In another preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R},(H2O) X ,(NaCl) Y (In the above formula, Q is approximately 0.085; R is approximately 0.031; X is about 0.34; and Y is approximately 0.14).

[0215] In a particularly preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH, (CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, T is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; Z is from 0.25 to 0.75, in particular from 0.35 to 0.65, preferably from 0.45 to 0.55, even more preferably about 0.51; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion such as a sodium ion or a potassium ion, preferably a sodium ion.

[0216] In another particularly preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH, (CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(NaCl) Y (In the above formula, T is between 0.08 and 0.09, preferably about 0.085; Z is 0.45 to 0.55, preferably about 0.51; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; and Y has a molecular weight of from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14.

[0217] In another particularly preferred embodiment, the ferric octasaccharide of the present invention has the formula: {FeOOH, (CH 10 O6) T- (C6H 10 O5)Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(NaCl) Y (In the above formula, T is about 0.085; Z is approximately 0.51; R is approximately 0.031; X is about 0.34; and Y is approximately 0.14).

[0218] In a particular embodiment, the ferric octasaccharide comprises a mixture of oligoisomaltosides having a weight average molecular weight in the range of 1150 to 1350 Da. In a particular embodiment, the octasaccharide comprises a mixture of oligoisomaltosides having a weight average molecular weight in the range of 1200 to 1300 Da, preferably 1225 to 1275 Da; for example, about 1250 Da.

[0219] In some embodiments, the ferric octasaccharide has an "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) in the range of 125,000 to 185,000 Da. In particular embodiments, the "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) of the ferric octasaccharide is in the range of 135,000 to 175,000 Da, preferably 140,000 to 155,000 Da. In certain embodiments, the "apparent" peak molecular weight (Mp) is in the range of 145,000 to 155,000 Da.

[0220] In some embodiments, the ferric octasaccharide has a monosaccharide and disaccharide content of less than 10.0% by weight of the octasaccharide. In certain embodiments, the monomer and dimer content is less than 3.0%, preferably less than 1.0% by weight of the octasaccharide; for example, 0.1 to 0.5%.

[0221] In some embodiments, the fraction of the ferric octasaccharide having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide. In certain embodiments, the fraction having more than 9 monosaccharide units is less than 35%, preferably less than 30% by weight of the octasaccharide; for example, 20 to 30%.

[0222] In some embodiments of the ferric octasaccharide, at least 40% by weight of the oligoisomaltoside molecules have 6 to 10 monosaccharide units. In certain embodiments, the proportion of molecules having 6 to 10 monosaccharide units is at least 45% by weight of the octasaccharide; e.g., 40 to 60% or 45 to 55%.

[0223] In some embodiments, the proportion of molecules with 6 to 10 monosaccharide units is greater by weight than the proportion of molecules with 3 to 6 monosaccharide units.

[0224] In some embodiments, the dispersity (Mw / Mn) of the ferric octasaccharide is in the range of 1.05 to 1.4. In certain embodiments, the dispersity (Mw / Mn) is in the range of 1.1 to 1.3; for example, about 1.2.

[0225] In some embodiments, the amount of reducing sugars in the ferric octasaccharide is 2.5% or less by weight of the octasaccharide. In certain embodiments, the amount of reducing sugars is 2.5% or less by weight of the octasaccharide; preferably 1.0% or less; more preferably 0.5% or less; for example, about 0.3%.

[0226] In some embodiments, the amount of reducing sugars in the ferric octasaccharide prior to hydrogenation is (i) at least 10% or at least 15%, and (ii) less than 35%; preferably 30% or less; for example, 10% to 30%, preferably 15 to 25% of the weight of the octasaccharide.

[0227] In some embodiments, the ferric octasaccharide comprises 10 to 50% iron by weight of the ferric octasaccharide, preferably 15 to 35%, most preferably 20 to 30%, e.g., 20 to 25%. In some embodiments, the weight ratio of elemental iron to octasaccharide in the ferric octasaccharide is 10:90 to 50:50, preferably 15:85 to 45:55, most preferably 20:80 to 40:60, e.g., about 70:30.

[0228] In some embodiments, the total amount of free iron in the ferric octasaccharide is less than 0.01% w / v for a 100 mg / mL solution; preferably, less than 0.003% w / v.

[0229] In another aspect of the present invention, there is provided a ferric octasaccharide comprising iron complexed with an octasaccharide, wherein (i) the octasaccharide has a weight average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6-10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is 2.5% or less by weight of the octasaccharide.

[0230] All of the above embodiments apply equally to this aspect.

[0231] Exemplary Implementations 1. A method for treating iron deficiency in a companion animal comprising administering an iron complex compound. 2. The method of embodiment 1, wherein the companion animal is a canine, feline or equine. 3. The method of embodiment 1, wherein the companion animal is a dog or a cat. 4. The method of embodiment 1, wherein the companion animal is a dog. 5. The method of any one of embodiments 1 to 4, wherein the companion animal has a reticulocyte hemoglobin content (CHr) / reticulocyte hemoglobin equivalent (RET-He) of 20 pg or less. 6. The method of any one of embodiments 1 to 4, wherein the iron deficiency is iron deficiency anemia. 7. The method of any one of embodiments 1 to 6, wherein the companion animal, preferably a dog or cat, has a hematocrit (HCT / PCV) of less than 35%. 8. The method of any one of embodiments 1 to 7, wherein the companion animal, preferably a dog or cat, has a hemoglobin concentration (Hb) of less than 12 g / dL. 9. The method of any one of embodiments 1 to 8, wherein the companion animal, preferably a dog or cat, has a mean corpuscular volume (MCV) of less than 60 fL. 10. The method of any one of embodiments 1-9, wherein the companion animal, preferably a dog or cat, has a mean corpuscular hemoglobin concentration (MCHC) of 30 g / dL or less. 11. The method of any one of embodiments 1 to 10, wherein the dosage is from 5 to 100 mg / kg of body weight; preferably from 10 to 60 mg / kg of body weight; most preferably from 15 to 25 mg / kg of body weight; for example, about 20 mg / kg of body weight. 12. The method of any one of embodiments 1 to 11, wherein the dosage is up to 50 mg iron / kg body weight; preferably up to 30 mg iron / kg body weight; most preferably up to 20 mg iron / kg body weight. 13. The method of any one of embodiments 1 to 12, wherein the dose is a single dose. 14. The method of any one of embodiments 1 to 13, wherein the dose is provided as a single administration, preferably an injection, in particular a subcutaneous injection. 15. The method of any one of embodiments 1 to 13, wherein the dose is provided as two, three or more administrations, preferably injections, in particular subcutaneous injections. 16. The method of any one of embodiments 1-12, wherein more than one dose is administered. 17. The method of embodiment 16, wherein the more than one dose is a dose of up to 50 mg iron / kg body weight; preferably up to 30 mg iron / kg body weight; most preferably up to 20 mg iron / kg body weight. 18. The method of embodiment 16 or 17, wherein the two sequential doses are administered within one month; preferably within two weeks; most preferably within one week. 19. The method of any one of embodiments 1 to 18, wherein the administration is subcutaneous. 20. The method of embodiment 19, wherein the site of subcutaneous administration is in the lateral upper back area behind the shoulder blades above the ribs, or in the paralumbar dorsal area. 21. The method of any one of embodiments 1 to 20, wherein the iron complex compound is an iron-sugar complex. 22. The method of embodiment 21, wherein the sugar is an oligosaccharide. 23. The method of embodiment 22, wherein the oligosaccharide is oligoisomaltose. 24. The method of embodiment 23, wherein the oligoisomaltose is hydrogenated oligoisomaltose (oligoisomaltoside). 25. The method of any one of embodiments 22 to 24, wherein the oligosaccharides have a weight average molecular weight (Mw) in the range of 850 to 1150 Da; preferably 950 to 1050 Da; most preferably 975 to 1025 Da; for example about 1000 Da. 26. The method of embodiment 25, wherein the proportion of molecules having 3 to 6 monosaccharide units is greater by weight than the proportion of molecules having 6 to 10 monosaccharide units. 27. The method of embodiment 25 or 26, wherein the proportion of molecules having 3 to 6 monosaccharide units is at least 40% by weight of the oligosaccharides; preferably at least 50%; for example, 40 to 70%, or 50 to 70%. 28. The method of any one of embodiments 25 to 27, wherein the fraction having more than 9 monosaccharide units is less than 30% by weight of the oligosaccharides; preferably less than 25%; most preferably less than 20%; for example, 5% to 15%. 29. The method of any one of embodiments 22 to 24, wherein the oligosaccharides have a weight average molecular weight (Mw) in the range of 1150 to 1350 Da; preferably 1200 to 1300 Da; most preferably 1225 to 1275 Da; for example about 1250 Da. 30. The method of embodiment 29, wherein the proportion of molecules having 6 to 10 monosaccharide units is greater by weight than the proportion of molecules having 3 to 6 monosaccharide units. 31. The method of embodiment 29 or 30, wherein the proportion of molecules having 6 to 10 monosaccharide units is at least 40% by weight of the oligosaccharides; preferably at least 45%; for example, 40 to 60%, or 45 to 55%. 32. The method of any one of embodiments 29 to 31, wherein the fraction having more than 9 monosaccharide units is less than 40% by weight of the oligosaccharides; preferably less than 35%; most preferably less than 30%; for example, 20% to 30%. 33. The method of any one of embodiments 22 to 32, wherein the content of monomers and dimers is less than 10.0% by weight of the oligosaccharide; preferably less than 3.0%; most preferably less than 1.0%; for example, 0.1 to 0.5%. 34. The method of any one of embodiments 22 to 33, wherein the amount of reducing sugars is 2.5% or less; preferably 1.0% or less; more preferably 0.5% or less; for example, about 0.3% by weight of the oligosaccharides. 35. The method of any one of embodiments 22 to 33, wherein the amount of reducing sugars is (i) at least 10% or at least 15%, and (ii) less than 35%; preferably less than 30%; for example, 10% to 30%, or preferably 15 to 25% of the weight of the oligosaccharides. 36. The method of any one of embodiments 22 to 35, wherein the iron oligosaccharide complex comprises 10 to 50%; preferably 15 to 35; most preferably 20 to 30%; for example, 20 to 25% iron, by weight of the iron oligosaccharide complex. 37. The method of any one of embodiments 22 to 36, wherein the weight ratio of elemental iron to oligosaccharide in the iron-oligosaccharide complex is from 10:90 to 50:50; preferably from 15:85 to 45:55; most preferably from 20:80 to 40:60; for example, about 70:30. 38. The method of any one of embodiments 22 to 37, wherein the "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) of the iron oligosaccharide complex is in the range of 120,000 to 190,000 Da; preferably 130,000 to 180,000 Da; or preferably 125,000 to 185,000 Da, more preferably 135,000 to 175,000 Da, and most preferably 140,000 to 155,000 Da. 39. The method of any one of embodiments 22 to 38, wherein the "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) of the iron oligosaccharide complex is in the range of 145,000 to 155,000 Da. 40. The method of any one of embodiments 22 to 39, wherein the dispersity (Mw / Mn) is in the range of 1.0 to 1.5; preferably 1.05 to 1.4; more preferably 1.1 to 1.3; for example, about 1.2. 41. The method of any one of embodiments 22 to 40, wherein the iron oligosaccharide complex comprises citric acid. 42. The method of embodiment 41, wherein the amount of citric acid is 3 to 20% by weight of the total amount of elemental iron. 43. The method of any one of embodiments 22 to 42, wherein the total amount of free iron is less than 0.01% w / v; preferably less than 0.003% w / v, relative to a 100 mg / mL solution of iron oligosaccharide complex. 44. The method of any one of embodiments 22 to 43, wherein the iron oligosaccharide complex comprises sodium chloride. 45. The method of any one of embodiments 22 to 44, wherein the iron oligosaccharide complex comprises water. 46. ​​The iron oligosaccharide complex, optionally containing a stabilizer and / or metal chloride and / or HO, has the formula: {FeOOH,(octasaccharide) Q} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085. The method of any one of embodiments 22 to 24 or 29 to 45, comprising: 47. The method of embodiment 46, wherein the iron oligosaccharide complex comprises citric acid. 48. The iron oligosaccharide complex, optionally containing metal chloride and / or HO, has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; and R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031. The method of any one of embodiments 22 to 24 or 29 to 47, comprising: 49. The method of any one of embodiments 46 to 48, wherein the iron oligosaccharide complex comprises sodium chloride. 50. The method of any one of embodiments 46 to 49, wherein the iron oligosaccharide complex comprises HO. 51. An iron oligosaccharide complex having the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion. The method of any one of embodiments 22 to 24 or 29 to 50, comprising: 52. The method of embodiment 51, wherein the monovalent metal ion is a sodium ion or a potassium ion. 53. The method of embodiment 52, wherein the monovalent metal ion is a sodium ion. 54. Q is 0.08 to 0.09, preferably about 0.085; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and The method of any one of embodiments 51 to 53, wherein Me is a sodium ion. 55. An iron oligosaccharide complex having the formula: {FeOOH,(CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, T is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; Z is from 0.25 to 0.75, in particular from 0.35 to 0.65, preferably from 0.45 to 0.55, even more preferably about 0.51; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion such as a sodium ion or a potassium ion, preferably a sodium ion. The method of any one of embodiments 22 to 24 or 29 to 54, comprising: 56. An iron oligosaccharide complex having the formula: {FeOOH,(CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(NaCl) Y (In the above formula, T is between 0.08 and 0.09, preferably about 0.085; Z is 0.45 to 0.55, preferably about 0.51; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; and Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14. The method of any one of embodiments 22 to 24 or 29 to 55, comprising: 57. A pharmaceutical composition comprising the iron complex compound of any one of embodiments 21 to 56 and a pharma- ceutically acceptable carrier. 58. The pharmaceutical composition of embodiment 57, which is a solid, preferably a powder, for reconstitution. 59. The pharmaceutical composition of embodiment 57, which is a ready-to-use fluid or a fluid for dilution before use. 60. A pharmaceutical composition of any one of embodiments 57 to 59, suitable for subcutaneous administration. 61. The pharmaceutical composition of any one of embodiments 57 to 60, comprising 1 to 25%; preferably 2 to 15%; most preferably 2.5 to 7.5 or 7.5 to 12.5; for example, about 5% or about 10% (w / v) elemental iron. 62. The pharmaceutical composition of any one of embodiments 57 to 61, wherein the concentration of the iron complex compound is 25 to 300 mg / mL; preferably 50 to 200 mg / mL; most preferably 75 to 150 mg / mL; for example, about 100 mg / mL elemental iron. 63. The pharmaceutical composition of any one of embodiments 57 to 62, wherein the pH is from 5.8 to 7.0; preferably from 5.9 to 6.8; most preferably from 5.9 to 6.6; for example, from 6.0 to 6.4. 64. The pharmaceutical composition of any one of embodiments 57 to 63, wherein the turbidity is less than 2.0 NTU; preferably less than 1.5 NTU; most preferably less than 1.0 NTU; for example less than 0.5. 65. The pharmaceutical composition of any one of embodiments 57-64, having a viscosity of 60 cP or less. 66. A pharmaceutical composition of any one of embodiments 57-65, having a shelf life of at least 3 years at 25°C. 67. A ferric octasaccharide comprising iron complexed with an octasaccharide, wherein (i) the octasaccharide has a weight average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6 to 10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is not more than 2.5% by weight of the octasaccharide. 68. The ferric octasaccharide of embodiment 67, wherein the octasaccharide has a weight average molecular weight (Mw) in the range of 1200 to 1300 Da; more preferably 1225 to 1275 Da; for example about 1250 Da. 69. The ferric octasaccharide of embodiment 67 or 68, in which the proportion of molecules having 6 to 10 monosaccharide units is greater by weight than the proportion of molecules having 3 to 6 monosaccharide units. 70. The ferric octasaccharide of any one of embodiments 67 to 69, wherein the proportion of molecules having 6 to 10 monosaccharide units is at least 45% by weight of the octasaccharide; for example, 40 to 60% or 45 to 55%. 71. The ferric octasaccharide of any one of embodiments 67 to 70, wherein the fraction having more than 9 monosaccharide units is less than 35% by weight of the octasaccharide; more preferably less than 30%; for example, 20 to 30%. 72. The ferric octasaccharide of any one of embodiments 67 to 71, wherein the content of monomers and dimers is less than 3.0% by weight of the octasaccharide; more preferably less than 1.0%; for example, 0.1 to 0.5%. 73. The ferric octasaccharide of any one of embodiments 67 to 72, wherein the amount of reducing sugar is 2.5% or less by weight of the octasaccharide; preferably 1.0% or less; more preferably 0.5% or less; for example, about 0.3% by weight. 74. The ferric octasaccharide of any one of embodiments 67 to 73, wherein the amount of reducing sugars before hydrogenation is (i) at least 10% or at least 15% and (ii) less than 35%; preferably less than 30%; for example, 10% to 30%, or preferably 15 to 25% of the weight of the octasaccharide. 75. The ferric octasaccharide of any one of embodiments 67 to 74, wherein the ferric octasaccharide comprises 10 to 50%; preferably 15 to 35; most preferably 20 to 30%; for example, 20 to 25% iron by weight of the ferric octasaccharide. 76. The ferric octasaccharide of any one of embodiments 67 to 75, wherein the weight ratio of elemental iron to octasaccharide in the ferric octasaccharide is from 10:90 to 50:50; preferably from 15:85 to 45:55; most preferably from 20:80 to 40:60; for example, about 70:30. 77. The ferric octasaccharide of any one of embodiments 67 to 76, wherein the "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) of the ferric octasaccharide is in the range of 135,000 to 175,000 Da, more preferably 140,000 to 155,000 Da. 78. The method of any one of embodiments 67 to 77, wherein the "apparent" peak molecular weight (Mp as measured by gel permeation chromatography) of the iron oligosaccharide complex is in the range of 145,000 to 155,000 Da. 79. The ferric octasaccharide of any one of embodiments 67 to 78, having a polydispersity (Mw / Mn) in the range of 1.1 to 1.3; for example, about 1.2. 80. The ferric octasaccharide of any one of embodiments 67 to 79, wherein the ferric octasaccharide comprises citric acid. 81. The ferric octasaccharide of embodiment 80, wherein the amount of citric acid is 3 to 20% by weight of the total amount of elemental iron. 82. The ferric octasaccharide of any one of embodiments 67 to 81, wherein the total amount of free iron is 0.01% w / v or less; preferably, less than 0.003% w / v, for a 100 mg / mL solution. 83. The ferric octasaccharide of any one of embodiments 67 to 82, wherein the ferric octasaccharide comprises sodium chloride. 84. The ferric octasaccharide of any one of embodiments 67 to 83, wherein the ferric octasaccharide comprises water. 85. The ferric octasaccharide, optionally containing a stabilizer and / or metal chloride and / or HO, has the formula: {FeOOH,(octasaccharide) Q} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085. The ferric octasaccharide of any one of embodiments 67 to 84, having the formula: 86. The ferric octasaccharide of embodiment 85, wherein the ferric octasaccharide comprises citric acid. 87. The ferric octasaccharide optionally contains metal chloride and / or HO, of the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; and R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031. The ferric octasaccharide of any one of embodiments 67 to 86, having the formula: 88. The ferric octasaccharide of any one of embodiments 85 to 87, wherein the ferric octasaccharide comprises sodium chloride. 89. The ferric octasaccharide of any one of embodiments 85 to 88, wherein the ferric octasaccharide comprises HO. 90. The ferric octasaccharide has the formula: {FeOOH,(octasaccharide)Q ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion. The ferric octasaccharide of any one of embodiments 67 to 89, having the formula: 91. The ferric octasaccharide of embodiment 90, wherein the monovalent metal ion is a sodium ion or a potassium ion. 92. The ferric octasaccharide of embodiment 91, wherein the monovalent metal ion is a sodium ion. 93. Q is 0.08 to 0.09, preferably about 0.085; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and The ferric octasaccharide of any one of embodiments 90 to 92, wherein Me is a sodium ion. 94. The ferric octasaccharide has the formula: {FeOOH,(CH 10 O6) T- (C6H 10 O5) Z- (C6H 13O5) T ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, T is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; Z is from 0.25 to 0.75, in particular from 0.35 to 0.65, preferably from 0.45 to 0.55, even more preferably about 0.51; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion such as a sodium ion or a potassium ion, preferably a sodium ion. The ferric octasaccharide of any one of embodiments 67 to 93, having the formula: 95. The ferric octasaccharide has the formula: {FeOOH,(CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(NaCl) Y (In the above formula, T is between 0.08 and 0.09, preferably about 0.085; Z is 0.45 to 0.55, preferably about 0.51; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; and Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14. The ferric octasaccharide of any one of embodiments 67 to 94, having the formula: 96. A ferric octasaccharide comprising iron complexed with an octasaccharide, the ferric octasaccharide optionally comprising a stabilizer and / or metal chloride and / or HO, of the formula: {FeOOH,(octasaccharide) Q} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085. A ferric octasaccharide having the formula: 97. The ferric octasaccharide of embodiment 96, wherein Q is 0.07 to 0.10, preferably 0.08 to 0.09, more preferably about 0.085. 98. The ferric octasaccharide of any one of embodiments 96 to 98, wherein the ferric octasaccharide comprises citric acid. 99. The ferric octasaccharide optionally contains metal chloride and / or HO, of the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R} (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; and R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031. The ferric octasaccharide of any one of embodiments 96 to 98, having the formula: 100. The ferric octasaccharide of embodiment 99, wherein R is 0.025 to 0.038, preferably 0.028 to 0.034, more preferably about 0.031. 101. The ferric octasaccharide of any one of embodiments 96 to 100, wherein the ferric octasaccharide comprises sodium chloride. 102. The ferric octasaccharide of any one of embodiments 96 to 101, wherein the ferric octasaccharide comprises water. 103. The ferric octasaccharide has the formula: {FeOOH,(octasaccharide) Q ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, Q is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion. The ferric octasaccharide of any one of embodiments 96 to 102, having the formula: 104. The ferric octasaccharide of embodiment 103, wherein X is 0.25 to 0.45, preferably 0.30 to 0.40, and more preferably about 0.34. 105. The ferric octasaccharide of embodiment 103 or 104, wherein Y is from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, and even more preferably about 0.14. 106. The ferric octasaccharide of any one of embodiments 103 to 105, wherein the monovalent metal ion is a sodium ion or a potassium ion. 107. The ferric octasaccharide of embodiment 106, wherein the monovalent metal ion is a sodium ion. 108. Q is 0.08 to 0.09, preferably about 0.085; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and The ferric octasaccharide of any one of embodiments 103 to 107, wherein Me is a sodium ion. 109. The ferric octasaccharide has the formula: {FeOOH,(CH 10 O6) T- (C6H 10 O5) Z- (C6H 13 O5) T ,(C6H8O7) R},(H2O) X ,(MeCl) Y (In the above formula, T is from 0.06 to 0.11, in particular from 0.07 to 0.10, preferably from 0.08 to 0.09, more preferably about 0.085; Z is from 0.25 to 0.75, in particular from 0.35 to 0.65, preferably from 0.45 to 0.55, even more preferably about 0.51; R is from 0.02 to 0.04, in particular from 0.025 to 0.038, preferably from 0.028 to 0.034, more preferably about 0.031; X is from 0.15 to 0.55, in particular from 0.25 to 0.45, preferably from 0.30 to 0.40, more preferably about 0.34; Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and Me is a monovalent metal ion such as a sodium ion or a potassium ion, preferably a sodium ion. The ferric octasaccharide of any one of embodiments 96 to 108, having the formula: 110. T is 0.08 to 0.09, preferably about 0.085; Z is 0.45 to 0.55, preferably about 0.51; R is 0.028 to 0.034, preferably about 0.031; X is 0.30 to 0.40, preferably about 0.34; and Y is from 0.05 to 1, in particular from 0.05 to 0.50, preferably from 0.09 to 0.40, preferably from 0.09 to 0.30, more preferably from 0.09 to 0.20, even more preferably about 0.14; and The ferric octasaccharide of any one of embodiments 109, wherein Me is a sodium ion. 111. The ferric octasaccharide of any one of embodiments 96 to 110, having a weight average molecular weight in the range of 1150 to 1350 Da, preferably 1200 to 1300 Da, more preferably 1225 to 1275 Da; for example about 1250 Da. 112. The ferric octasaccharide of any one of embodiments 96 to 111, having an "apparent" peak molecular weight (Mp measured by gel permeation chromatography) in the range of 125,000 to 185,000 Da, preferably in the range of 135,000 to 175,000 Da, more preferably in the range of 140,000 to 155,000 Da, for example in the range of 145,000 to 155,000 Da. 113. The ferric octasaccharide of any one of embodiments 96 to 112, wherein the ferric octasaccharide has a monosaccharide and disaccharide content of less than 10.0% by weight of the octasaccharide, preferably less than 3.0% by weight of the octasaccharide, more preferably less than 1.0%; for example, 0.1 to 0.5%. 114. The ferric octasaccharide of any one of embodiments 96 to 113, wherein the fraction of the ferric octasaccharide having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide, preferably less than 35% by weight of the octasaccharide, more preferably less than 30%; for example, 20 to 30%. 115. The ferric octasaccharide of any one of embodiments 96 to 114, wherein the proportion of molecules having 6 to 10 monosaccharide units is at least 40% by weight of oligoisomaltoside molecules, preferably at least 45%; for example, 40 to 60% or 45 to 55% by weight of the octasaccharide. 116. The ferric octasaccharide of any one of embodiments 96 to 115, wherein the proportion of molecules having 6 to 10 monosaccharide units is greater by weight than the proportion of molecules having 3 to 6 monosaccharide units. 117. The ferric octasaccharide of any one of embodiments 96 to 116, wherein the polydispersity (Mw / Mn) of the ferric octasaccharide is in the range of 1.05 to 1.4, preferably in the range of 1.1 to 1.3; for example about 1.2. 118. The ferric octasaccharide of any one of embodiments 96 to 117, wherein the amount of reducing sugars in the ferric octasaccharide is 2.5% by weight or less of the octasaccharide, preferably 2.5% by weight or less of the octasaccharide; preferably 1.0% or less; more preferably 0.5% or less; for example about 0.3%. 119. The ferric octasaccharide of any one of embodiments 96 to 118, wherein the amount of reducing sugars in the ferric octasaccharide before hydrogenation is (i) at least 10% or at least 15% and (ii) less than 35%; preferably less than 30%; for example, 10% to 30% or preferably 15 to 25% by weight of the octasaccharide. 120. The ferric octasaccharide of any one of embodiments 96 to 119, wherein the ferric octasaccharide comprises 10 to 50%; preferably 15 to 35; most preferably 20 to 30%; for example, 20 to 25% iron by weight of the ferric octasaccharide. 121. The ferric octasaccharide of any one of embodiments 96 to 120, wherein the weight ratio of elemental iron to octasaccharide in the ferric octasaccharide is from 10:90 to 50:50; preferably from 15:85 to 45:55; most preferably from 20:80 to 40:60; for example about 70:30. 122. The ferric octasaccharide of any one of embodiments 96 to 121, wherein the total amount of free iron in the ferric octasaccharide is 0.01% w / v or less; preferably less than 0.003% w / v, for a 100 mg / mL solution. 123. A pharmaceutical composition comprising the ferric octasaccharide of any one of embodiments 67 to 122 and a pharma- ceutically acceptable carrier. 124. The pharmaceutical composition of embodiment 123, which is a solid, preferably a powder, for reconstitution. 125. The pharmaceutical composition of embodiment 123, which is a ready-to-use fluid or a fluid for dilution before use. 126. The pharmaceutical composition of any one of embodiments 123 to 125, which is suitable for subcutaneous administration. 127. The pharmaceutical composition of any one of embodiments 123 to 126, comprising 1 to 25%; preferably 2 to 15%; most preferably 2.5 to 7.5 or 7.5 to 12.5; for example, about 5% or about 10% (w / v) elemental iron. 128. The pharmaceutical composition of any one of embodiments 123 to 127, wherein the concentration of the iron complex compound is 25 to 300 mg / mL; preferably 50 to 200 mg / mL; most preferably 75 to 150 mg / mL; for example about 100 mg / mL of elemental iron. 129. The pharmaceutical composition of any one of embodiments 123 to 128, wherein the pH is 5.8 to 7.0; preferably 5.9 to 6.8; most preferably 5.9 to 6.6; for example 6.0 to 6.4. 130. The pharmaceutical composition of any one of embodiments 123-129, wherein the turbidity is less than 2.0 NTU; preferably less than 1.5 NTU; most preferably less than 1.0 NTU; for example less than 0.5. 131. The pharmaceutical composition of any one of embodiments 123-130, having a viscosity of 60 cP or less. 132. The pharmaceutical composition of any one of embodiments 123 to 131, having a shelf life of at least 3 years at 25°C. 133. The ferric octasaccharide of any one of embodiments 67 to 122, or the pharmaceutical composition of any one of embodiments 123 to 132, for use in a method for treating iron deficiency in a human or non-human subject. 134. The ferric octasaccharide or pharmaceutical composition of embodiment 133, wherein the non-human subject is a companion animal. 135. The ferric octasaccharide or pharmaceutical composition of embodiment 134, wherein the companion animal is a canine, feline, or equine. 136. The ferric octasaccharide or pharmaceutical composition of embodiment 134, wherein the companion animal is a dog or a cat. 137. The ferric octasaccharide or pharmaceutical composition of embodiment 134, wherein the companion animal is a dog. 138. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 137, wherein the companion animal has a reticulocyte hemoglobin content (CHr) / reticulocyte hemoglobin equivalent (RET-He) of 20 pg or less. 139. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 138, wherein the iron deficiency is iron deficiency anemia. 140. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 139, wherein the companion animal, preferably a dog or cat, has a hematocrit (HCT / PCV) of less than 35%. 141. The ferric octasaccharide or pharmaceutical composition of any one of embodiments 134 to 140, wherein the companion animal, preferably a dog or cat, has a hemoglobin concentration (Hb) of less than 12 g / dL. 142. The ferric octasaccharide or pharmaceutical composition of any one of embodiments 134 to 141, wherein the companion animal, preferably a dog or cat, has a mean corpuscular volume (MCV) of less than 60 fL. 143. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 142, wherein the companion animal, preferably a dog or cat, has a mean corpuscular hemoglobin concentration (MCHC) of 30 g / dL or less. 144. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 143, wherein the dosage is from 5 to 100 mg per kg of body weight; preferably from 10 to 60 mg per kg of body weight; most preferably from 15 to 25 mg per kg of body weight; for example, about 20 mg per kg of body weight. 145. The ferric octasaccharide or pharmaceutical composition of any one of embodiments 134 to 144, wherein the dosage is up to 50 mg iron / kg body weight; preferably up to 30 mg iron / kg body weight; most preferably up to 20 mg iron / kg body weight. 146. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 145, wherein a single dose is administered. 147. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 146, wherein the dose is provided as a single (1) administration, preferably as an injection, in particular a subcutaneous injection. 148. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 146, wherein the dose is provided in two, three or more administrations, preferably as an injection, in particular a subcutaneous injection. 149. The ferric octasaccharide or pharmaceutical composition of any one of embodiments 134 to 145, wherein more than one dose is administered. 150. The ferric octasaccharide or pharmaceutical composition for use in embodiment 149, wherein the more than one dose is a dose of up to 50 mg iron / kg body weight; preferably up to 30 mg iron / kg body weight; most preferably up to 20 mg iron / kg body weight. 151. The ferric octasaccharide or pharmaceutical composition for use in embodiment 149 or 150, wherein two successive doses are administered within one month; preferably within two weeks; most preferably within one week. 152. The ferric octasaccharide or pharmaceutical composition for use according to any one of embodiments 134 to 151, wherein administration is subcutaneous administration. 153. The ferric octasaccharide or pharmaceutical composition for use in embodiment 152, wherein the site of subcutaneous administration is in the lateral upper dorsal area behind the scapula above the ribs, or in the paralumbar dorsal area. 154. The ferric octasaccharide or pharmaceutical composition for use according to embodiment 134, wherein a single dose of 20 mg / kg body weight is administered subcutaneously to dogs or cats.

[0232] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, and represented in a specific form thereof or by means for performing a disclosed function or a method or process for suitably obtaining a disclosed result, may be utilized separately or in any combination of such features to realize the invention in diverse forms thereof.

[0233] While the present invention has been described in conjunction with the exemplary embodiments set forth above, many equivalent modifications and variations will become apparent to those skilled in the art given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes can be made to the described embodiments without departing from the spirit and scope of the invention.

[0234] For the avoidance of doubt, any theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0235] Any section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0236] Throughout this specification, including the claims which follow, unless the context requires otherwise, the words "comprise" and "include", and variations such as "comprises", "comprising" and "including", will be understood to imply the inclusion of a specified integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0237] As used herein and in the appended claims, it should be noted that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges can be expressed herein as from one particular value and / or to another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Those of skill in the art will understand that such values ​​are only as precise as the method used to measure them, and therefore will understand that values ​​disclosed herein are accompanied by a margin of error. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value constitutes another embodiment. As used herein, the term "about" refers to the stated value of a variable and all values ​​of the variable that are within experimental error of the stated value (e.g., within a 95% confidence interval of the mean) or within 10% of the stated value, whichever is greater. EXAMPLES

[0238] Example 1 – Preparation of ferric oligoisomaltoside Ferric oligoisomaltoside was produced from various dextran fractions that were combined and fractionated by ultrafiltration. The dextran fractions were generated from intermediate dextran. In several steps, the starting material was hydrolyzed to lower molecular weight, fractionated by ultrafiltration, and filtered until the desired molecular weight distribution was achieved. The oligoisomaltose was finally hydrogenated and ion-exchanged, then reacted with ferric chloride to form a complex.

[0239] [Production of ferric octasaccharide] [Sugar fractionation] Prehydrolyzed dextran fractions with weight average molecular weights estimated to be approximately 2 kDa to 5 kDa (4872 kDa) were hydrolyzed to pH 1.5 by addition of concentrated HCl, and the chromatographic peak rise was compared with that of an external dextran standard (M w The mixture was stirred at 90° C. until the molecular weight (molecular weight) matched that of the sucrose ester (<2 kDa). The solution was cooled to 28° C. and neutralized with NaOH. The solution was purified by diafiltration against water at 51° C. until a narrow distribution of molecular weight between 1150 and 1350 Da and a polydispersity of about 1.2 was achieved. The amount of reducing sugars determined by Somogyi's reagent was 21%.

[0240] [Hydrogenation of sugars] The resulting fraction (1652 kg) was treated with sodium borohydride at pH 10.2 at 28° C. The level of reducing sugars measured by Somogyi's reagent was less than 0.02%. The solution was acidified to pH 2.0 with concentrated HCl, stirred for 3 hours, and then the pH was adjusted to 4.6 with NaOH.

[0241] The solution was deionized by ion exchange to give a product solution containing the octasaccharide with a conductivity of less than 500 μS / cm.

[0242] The weight-average molecular weight (Mw) of the octasaccharide was determined to be 1235 Da.

[0243] [Iron complexation] For complexation, 560 kg of octasaccharide and 240 kg of elemental iron from ferric chloride were used. A solution containing 70 kg of octasaccharide was added to the complexation reactor. Water for injection (WFI) was added with stirring, followed by FeCl3,6H2O equivalent to 240 kg of elemental iron. NaOH was added to a pH of about 10.5, followed by 600 kg of Na2CO3 (aq) with stirring. The solution was heated to above 100°C until the solution became a black or dark brown colloidal solution. The solution was then neutralized using HCl and filtered. The solution was purified by membrane filtration to remove unbound octasaccharide, free iron, and residual inorganic salts. Citric acid monohydrate dissolved in sodium hydroxide was added. The pH was adjusted to 5.6, and the resulting solution was spray dried to obtain a black to dark brown powder.

[0244] The "apparent" peak molecular weight (Mp) of the ferric octasaccharide complex was determined to be 147121 Da, and the Mw / Mn (dispersity) was calculated to be 1.15. For this purpose, the composition was diluted to 0.1% iron (1 mg / mL) in the eluent and the chromatogram was measured by GPC (+ reference standards, dextran and ferric dextran). The Mp was read from the chromatogram and the Mn and Mw were calculated using the calibration curve.

[0245] [Complex strength] The absorbance (287.3 nm) after acid hydrolysis is proportional to the amount of complexed iron. The absorbance is measured over time. T1 / 2 is the time it takes for half of the original complexed iron to be released. The sample was diluted to 0.02% = 200 mg / L iron. 5 mL of the diluted sample was hydrolyzed in 100 mL of 0.25 M HCl containing 0.9 g NaCl.

[0246] The complex strength of the resulting ferric octasaccharide was found to be high. When subjected to hydrochloric acid hydrolysis under the test conditions, it took 40 hours for half of the complex to dissociate into its constituent parts (iron and sugar). This T1 / 2 is lower than that usually observed for ferric dextran and ferric dextran glucoheptonate complexes (which typically range from 70 to 80 hours, depending on the type of dextran and complex). At the same time, the T1 / 2 is higher than that observed for complexes with weakly bound iron, such as ferric sucrose or ferric gluconate.

[0247] [Free iron] The amount of free iron (i.e., colloidal iron less than 12-14 kDa in size) in compositions containing iron-sugar complexes was quantified by dialysing the iron into clean water and measuring the amount of iron in the dialysate by atomic absorption spectroscopy.

[0248] 3mL of the natural composition was dialyzed in 20mL of water for 24 hours in a dialysis tube.The amount of iron in the dialysate was then quantified.Free iron% was calculated as the iron in the dialysate relative to the total amount of iron in 3mL of the composition.

[0249] The amount of free iron in the ferric octasaccharide was determined to be less than 0.003% w / v, indicating that the product is safe.

[0250] [Iron and sugar content] To determine the sugar content, the composition containing the iron-sugar complex was diluted, and all the glucose in the complex was released and bound with anthrone-HCl. The amount of glucose was measured spectrophotometrically.

[0251] The sugar content in the ferric octasaccharide composition with 10% w / v iron concentration was found to be as high as 22% w / v. This is significantly higher than the sugar content typically observed in ferric dextran and ferric dextran glucoheptonate complexes (which can be as low as half the value for ferric octasaccharide depending on the type of dextran and complex). In other words, the iron to sugar ratio in ferric octasaccharide is lower than that of typical ferric dextran and ferric dextran glucoheptonate complexes. This in turn means that the individual iron particles (akaganeite particles) are better protected by glucose units, improving their physical stability.

[0252] [Further production of oligoisomaltoside iron] Using essentially the same process steps, further ferric oligoisomaltosides were produced with the aim of producing oligoisomaltosides and iron complexes with different molecular weight distributions than the ferric octasaccharide. For example, in a separate process, fractionation was performed so that the resulting oligoisomaltosides had lower weight average molecular weights (measured by GPC) ranging from 850 to 1150 Da. For example, one such oligoisomaltoside had a weight average molecular weight of 1047 Da. The corresponding iron complexes were found to have complex strengths (T1 / 2 = 33 to 37 hours) comparable to the ferric octasaccharide, but the sugar content (about 18% w / v) was slightly but significantly lower than in the ferric octasaccharide when measured at the same iron concentration.

[0253] Example 2 - Study to evaluate the tolerability, safety, pharmacokinetics (PK) and pharmacodynamics (PD) of ferric oligoisomaltoside injected subcutaneously (SC) and intramuscularly (IM) in healthy laboratory dogs (not ID or IDA) [Research purpose] This pilot study was designed to investigate the treatment of dogs with ferric oligoisomaltoside. Specific objectives included: determining the serum and urinary iron pharmacokinetic profile; determining the pharmacodynamic profile of hemoglobin, reticulocyte count, calcium, ferritin, unsaturated iron binding capacity, total iron binding capacity, and transferrin saturation; assessing injection site reactions through routine monitoring; and determining the dog's tolerance to injections of the compound and the initial safety profile of the compound based on clinical pathology.

[0254] This single-center, nonclinical laboratory study in dogs included four dose groups in an open-label, randomized, parallel design. Fourteen male and 14 female dogs were acclimated to study conditions for 7 days during which they were weighed, physically examined, blood collected for hematology and clinical chemistry analyses, urine collected for urinalysis, and clinical observations twice daily.

[0255] After acclimation, 24 beagle dogs (12 males and 12 females; weighing 7.2 to 12.4 kg) were randomized into one of four gender-balanced dose groups of six dogs each. The dogs were administered a single dose of ferric oligoisomaltoside (compound produced according to Example 1; 100 mg / mL elemental iron; pH=6.3) according to the following table. The intended 1× dose is 20 mg / kg, or 0.2 mL / kg. In group T3, the dose is 100 mg / kg, or 1 mL / kg. For example, dogs weighing 10.3 kg in group T2 were administered 6.2 mL of ferric oligoisomaltoside. TIFF2024529536000002.tif42170

[0256] To define the injection site location assessment, a thin outline of the left paralumbar region encompassing both the IM and SC sites was shaved prior to Day 0. This outline allowed all technicians to perform the injection site assessment within a consistent area. Shaving of the injection site was not permitted. Ferric oligoisomaltoside was administered by SC (left paralumbar) or IM (left paralumbar ectaxial) injection.

[0257] For SC injection (groups T1, T2, and T3): The dose was taken into the syringe and all air was removed; · Dogs were restrained to prevent movement during injections; · Skin exploration of the left paralumbar region; ·The needle was inserted into the SC space and negative pressure was applied to the plunger to ensure that the needle was in the SC space and not in the vascular territory; The entire intended dose was injected and the needle was removed from the skin; Pain was assessed immediately after needle placement while injecting the test substance; The dogs were returned to their cages and the handler changed gloves after each dog.

[0258] For IM injection (group T4): The dose was taken into the syringe and all air was removed; · Dogs were restrained to prevent movement during injections; · Left dorsal paralumbar (epicardial) muscle identified; ·The needle was inserted into the muscle and negative pressure was applied to the plunger to ensure that the needle was within the muscle and not in the vascular area; The entire intended dose was injected and the needle was removed from the muscle; Pain was assessed immediately after needle placement while injecting the test substance; The dogs were returned to their cages and the handler changed gloves after each dog.

[0259] Study variables were assessed as follows: Tolerance to injection was assessed during dose administration; Serial blood samples were taken for pharmacokinetic and pharmacodynamic analysis at 0.05 s after administration. 1 , were conducted at 0.5, 1, 2, 4, 8, 24, 48, 72, 120, 168, 240, 336, and 504 hours; · Urine for pharmacokinetic analysis was collected at intervals of 0 to 8, 8 to 24, 24 to 48, and 48 to 72 hours after dosing; · Clinical observations were performed twice a day (at least 6 hours apart) from the first day of acclimatization until the last day of the study; Injection site assessments were performed on days 0, 1, 2, and 6 hours (all ±15 minutes) pre-dose, 24, 48, and 72 hours (±1 hour), and days 4, 7, 10, 14, and 21 (±1 hour post-dose); Physical examinations were performed once during acclimation (day -6) and on day 21; Body weight was measured once during acclimation (day -7) and on days 0 (before dosing), 7 and 21; ( 1 Pre-dose (0 hour) PK and PD samples were collected on Day -1 for all dogs. Blood for clinical pathology was collected once during acclimation (day -5) and on days 2, 7, and 21; · Urine was collected for urinalysis once during acclimation (day -7 or -5) and on days 1 or 2, 7 or 8, and 20 or 21; Food intake was measured from the first day of acclimation until the end of the study.

[0260] [result] AUC tlast and C max After baseline adjustment for serum iron concentrations to determine baseline-adjusted AUC tlast The values ​​were significantly lower in groups T1 and T4 compared with groups T2 and T3. max Values ​​were significantly lower in group T1 compared with group T3; other comparisons were not statistically significant.

[0261] The main findings of the study can be summarized as follows: · SC (T1) injection was relatively less painful than IM (T4 at 20mg / kg dose). SC injection of 20mg / kg (T1) was relatively less painful than SC injection of 100mg / kg (T3). TIFF2024529536000003.tif65170·No cases of heat, pain, or swelling at the injection site after administration were recorded in any dog ​​during the study period, and no other drug-related adverse events were reported. Surprisingly, however, T1 injected at 20 mg / kg SC showed essentially the same serum iron pharmacokinetic profile as T4 injected at 20 mg / kg IM. See Figure 1. And surprisingly, a dose-related increase in ferritin was observed, with the T1 and T4 profiles showing essentially the same ferritin response, and the T2 and T3 showing proportionally greater responses; see Figure 2.

[0262] [Conclusion] Overall, ferric oligoisomaltoside was well tolerated at all dosage levels and both routes of administration. The dogs were in good health throughout the course of the study.

[0263] The PK profile demonstrated the AUC values ​​for both serum and urinary iron concentrations after injection of ferric oligoisomaltoside in dogs. tlast and C max In serum, the baseline-adjusted AUC tlast and C max A statistically significant dose effect on serum iron was detected using the parameter AUC tlast and C. max There was no significant difference between the T4(1×IM) and T1(1×SC) groups, indicating that the route of administration of ferric oligoisomaltoside did not significantly affect the PK profile. The route of administration (IM vs. SC) also did not affect any of the PD parameters, as no significant differences were observed between the T4(1×IM) and T1(1×SC) groups. Comparable PD profiles were observed in the T4(1×IM) and T1(1×SC) groups.

[0264] In urine, cumulative iron excretion demonstrated a short-term dose effect, but this effect disappeared by the end of the sampling period. Route of administration did not significantly affect cumulative urinary iron excretion.

[0265] Reticulocyte count and calcium, and most PD parameters, showed consistent short-term dose-proportional effects. Ferritin and TSAT increased in a dose-proportional manner. Effects on ferritin and TSAT were also demonstrated in the T1 (1 × SC) and T4 (1 × IM) treatment groups.

[0266] Since ferritin has been found to increase in a dose-dependent manner and treatment of iron-deficient subjects with parenteral iron compounds would be expected to increase ferritin, it is reasonable to expect that subcutaneous injections of ferric oligoisomaltoside would be suitable for the treatment of iron deficiency and iron deficiency anemia in dogs and other companion animals.

[0267] Example 3 - Absorption of ferric octasaccharide in rabbits after subcutaneous (SC) or intramuscular (IM) injection [Research purpose] A 10% (w / v) composition containing ferric octasaccharide was injected IM or SC into the leg of rabbits at 0.4 mL / kg body weight, while the other leg served as a control. The rabbits were euthanized after 24 hours or 7 days.

[0268] In the case of IM injections, absorption was assessed by checking how much iron remained in the injected muscle, both visually and by quantitative assessment. For quantitative assessment, the muscle was homogenized and subjected to disruption with NaOH followed by H2SO4 / HNO3 boiling at 140°C for 20 hours. The amount of iron in the disrupted samples was then quantified by atomic absorption spectrometry (AAS; see British Pharmacopoeia latest edition: Iron Dextran Injection, "Test for Iron Absorption" - modified) and the fraction of iron remaining at the injection site - i.e. the iron that was not absorbed from the injection site - was calculated. The fraction of iron absorbed was then calculated as 100% minus the fraction of iron remaining at the injection site.

[0269] For SC injections, the same procedure was followed as for IM injections with one exception: the whole muscle and skin were analyzed, i.e., the muscle was not skinned prior to analysis.

[0270] [result] Ferric octasaccharide was well and rapidly absorbed from the injection site, both intramuscularly and subcutaneously. After 7 days, 98-99% of the dose was absorbed from the injection site, with no significant differences observed between subcutaneous and intramuscular injections. Within a short time frame of 24 hours after injection, absorption of intramuscularly administered iron was found to be essentially complete (99.4%), whereas subcutaneously administered iron was still not completely absorbed (96.3%).

[0271] [Conclusion] Seven days after injection, the iron in the ferric octasaccharide was found to be completely absorbed from the injection site. No significant differences were observed between subcutaneous and intramuscular injections. Surprisingly, absorption of iron within the first 24 hours from the ferric octasaccharide administered subcutaneously was observed to be nearly as rapid as that from intramuscular administration (96.3% vs. 99.4%). While intramuscular administration would be expected to result in relatively rapid absorption of iron, absorption of iron from subcutaneously administered iron complex compounds would normally be expected to be significantly slower.

[0272] [References] A number of publications have been cited above in order to more fully describe and disclose the present invention and the state of the art to which it pertains. Full citations for these references are provided below. Each of these references is incorporated herein in its entirety.

[0273] Bohn, AA (2013). Diagnosis of Disorders of Iron Metabolism in Dogs and Cats. Veterinary Clinics: Small Animal Practice, 43(6), 1319-30. Cohen-Solal, A., Leclercq, C., Deray, G., Lasocki, S., Zambrowski, JJ, Mebazaa, A., Groote, P., Damy, T., and Galinier, M. (2014). Iron deficiency: an emerging therapeutic target in heart failure. Heart, 100(18), 1414-20. Cook, A.K., & Kvitko-White, H. L. (2014). DVM360 - Case report June 1st 2014: A 5-year-old golden retriever with IDA, http: / / veterinarymedicine.dvm360.com / case-report-5-year-old-golden-retriever-with-ida (accessed September 3, 2019). Dignass, A. U., Gasche, C., Bettenworth, D., Birgegard, G., Danese, S., Gisbert, J. P.,... & Vavricka, S. (2015). European consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases. Journal of Crohn’s and Colitis, 9(3), 211 - 22. Fry, M. M., & Kirk, C. A. (2006). Reticulocyte indices in a canine model of nutritional iron deficiency. Veterinary Clinical Pathology, 35(2), 172 - 81. Fuchs, J., Moritz, A., Grusendorf, E., Lechner, J., Neuerer, F., Nickel, R., Rieker, T., Schwede (2017). Evaluation of reticulocyte hemoglobin content (RET-He) in the diagnosis of iron deficient erythropoiesis in dogs. Veterinary Clinical Pathology, 46(4), 558 - 68. Giger, U. (2005). In Ettinger, SJ and Feldman, EC-Textbook of Veterinary Internal Medicine.Chapter 270: Regenerative anemias caused by blood loss or hemolysis, 1888-90.6 edition Elsevier. Giger, U. (2010). In Weiss, DJ and Wardrop, K, J.-Schalm's Veterinary Hematology. Chapter 28: Hereditary Erythrocyte Enzyme Abnormalities, 183-5.6 edition Wiley-Blackwell. Harvey, JW, French, TW, and Meyer, DJ (1982). Chronic iron deficiency anemia in dogs. Journal of the American Animal Hospital Association, 18(6), 946-60. Lund, E. (2007). Population analyses of anemia in Pets - Banfield DataSavant analysis, 2007. https: / / www.banfield.com / getmedia / 8b7bab32-5503-43f1-aebd-4fdf558e5d0d / 3_5-Population-Analysis-of-Anemia-in-Pets (Accessed September 3, 2019). Merck Veterinary Manual, Reference Guides, Hematologic Reference Ranges. https: / / www.merckvetmanual.com / special-subjects / reference-guides / hematologic-reference-ranges (accessed August 29, 2019). Naigamwalla, D.Z., Webb, J.A., and Giger, U. (2012). Iron deficiency anemia. The Canadian Veterinary Journal, 53(3), 250 - 6. Nelson, R.W. and Couto, C.G. (1998). Small Animal Internal Medicine. Chapter 85, 1171 - 2. 2nd edition Elsevier. Olver, C.S., Andrews, G.A., Smith, J.E., and Kaneko, J.J. (2010). In Weiss, D.J. and Wardrop, K, J. - Schalm’s Veterinary Hematology. Chapter 20: Erythrocyte Structure and Function, 123 - 9. 6th edition Wiley - Blackwell. Plumb, D.C. (2008). Plumb’s Veterinary Drug Handbook. Pages 382 - 3 and 493 - 4. 6th edition Blackwell Publishing. Preusser, L.C., Fryer F.M., Gerhardt, A., Yanhui Hu, Delgado - Herrera L., Melnick, J.Z., Williams, L.A., Cox, B.F., and Reinhart, G.A. (2005). Clinical and Experimental Pharmacology and Physiology, 32, 1020 - 1026 Prins, M., van Leeuwen, M. W., Teske, E. (2009). Stability and reproducibility of ADVIA 120-measured red blood cell and platelet parameters in dogs, cats, and horses, and the use of reticulocyte haemoglobin content (CHr) in the diagnosis of iron deficiency. Tijdschrift voor Diergeneeskunde (Journal of Veterinary Medicine), 134(7), 272-8。 Schaefer, D. M. W. and Stokol, T. (2015). The utility of reticulocyte indices in distinguishing iron deficiency anemia from anemia of inflammatory disease, portosystemic shunting, and breed-associated microcytosis in dogs. Veterinary Clinical Pathology, 44(1), 109-19。 Steinberg, J. D. and Olver, C. S. (2005). Hematologic and biochemical abnormalities indicating iron deficiency are associated with decreased reticulocyte hemoglobin content (CHr) and reticulocyte volume (rMCV) in dogs - Veterinary Clinical Pathology, 34(1), 23-7。 Thrall, M. A. and Gillespie, B.9(2011). Diagnosis of Iron Deficiency Anemia, VetCom Winter 2011 Tvedten, H. (2010). In Weiss, D. J. and Wardrop, K, J. - Schalm’s Veterinary Hematology. Chapter 24: Laboratory and Clinical Diagnosis of Anemia, 152 - 9. 6th edition Wiley - Blackwell. Weiser, G. (2015). In Tilley, L. P. and Smith Jr, F. W. - Blackwell’s Five - Minute Veterinary Consult: Canine and feline. Anemia: Iron - Deficiency, page 83. 6th edition John Wiley & Sons. Weiss, D. J. (2010). In Weiss, D. J. and Wardrop, K, J. - Schalm’s Veterinary Hematology. Chapter 26: Iron and Copper Deficiencies and Disorders of Iron Metabolism, 167 - 71. 6th edition Wiley - Blackwell.

Claims

1. A medicament comprising an iron complex compound for subcutaneous use in a method for treating iron deficiency in a companion animal.

2. The pharmaceutical composition according to claim 1, wherein the iron deficiency is iron deficiency anemia.

3. 3. The method of claim 1 or 2, wherein the companion animal is a dog or a cat, optionally a cat with chronic kidney disease (CKD).

4. The pharmaceutical described in claim 3, wherein the companion animal is a cat with chronic kidney disease (CKD), and the method comprises administering an erythropoiesis stimulating agent in addition to the iron complex compound, and optionally the erythropoiesis stimulating agent is erythropoietin or darbepoetin alfa.

5. 3. The method of claim 1, wherein the method comprises administering elemental iron at a dose of 20 mg / kg body weight.

6. The pharmaceutical composition according to claim 1 or 2, wherein the iron complex compound is an iron oligoisomaltose complex or an iron oligoisomaltoside complex.

7. 3. The pharmaceutical composition of claim 1, wherein the iron complex compound is an iron octasaccharide complex comprising iron complexed with an octasaccharide, wherein (i) the octasaccharide has a weight-average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6 to 10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is 2.5% by weight or less of the octasaccharide.

8. A pharmaceutical composition for subcutaneous administration comprising an iron complex compound and a pharmaceutically acceptable carrier.

9. 9. The pharmaceutical composition of claim 8, which is a ready-to-use injectable composition.

10. 10. The pharmaceutical composition of claim 8 or 9, comprising 100 mg / mL elemental iron.

11. 10. The pharmaceutical composition according to claim 8 or 9, wherein the iron complex compound is an iron oligoisomaltose complex or an iron oligoisomaltoside complex.

12. 10. The pharmaceutical composition of claim 8 or 9, wherein the iron complex compound is an iron octasaccharide complex comprising iron complexed with an octasaccharide, and wherein (i) the octasaccharide has a weight-average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6 to 10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is 2.5% by weight or less of the octasaccharide.

13. 1. An iron octasaccharide complex comprising iron complexed with an octasaccharide, wherein (i) the octasaccharide has a weight average molecular weight in the range of 1150 to 1350 Da; (ii) the content of monosaccharides and disaccharides is less than 10.0% by weight of the octasaccharide; (iii) the fraction having more than 9 monosaccharide units is less than 40% by weight of the octasaccharide; (iv) at least 40% by weight of the molecules have 6 to 10 monosaccharide units; (v) the "apparent" peak molecular weight (Mp) of the octasaccharide complex is in the range of 125,000 to 185,000 Da; (vi) the dispersity (Mw / Mn) of the complex is in the range of 1.05 to 1.4; and (vii) the amount of reducing sugars is 2.5% by weight or less of the octasaccharide.

14. An iron octasaccharide complex as described in claim 13, wherein the octasaccharide has a weight average molecular weight (Mw) in the range of 1200 to 1300 Da, preferably in the range of 1225 to 1275 Da, and / or the weight proportion of molecules having 6 to 10 monosaccharide units is greater than the weight proportion of molecules having 3 to 6 monosaccharide units.

15. A pharmaceutical composition comprising the iron octasaccharide complex of claim 13 or 14 and a pharmaceutically acceptable carrier.

16. 15. A medicament comprising the iron octasaccharide complex of claim 13 or 14 for use in a method of treating iron deficiency in a human or non-human subject.

17. The pharmaceutical described in claim 16, wherein the non-human subject is a companion animal selected from a dog or a cat, optionally a cat with chronic kidney disease (CKD).

18. The pharmaceutical described in claim 17, wherein the companion animal is a cat with chronic kidney disease (CKD), and the method comprises administering an erythropoiesis stimulating agent in addition to the iron complex compound, optionally wherein the erythropoiesis stimulating agent is erythropoietin or darbepoetin alfa.

19. The pharmaceutical composition according to claim 16, wherein the iron deficiency is iron deficiency anemia.

20. A combination of an iron complex compound and one or more additional agents, wherein the additional agents are: (1) Erythropoiesis-stimulating agents (ESAs); (2) hepcidin modulators; (3) antiparasitic drugs; (4) chemotherapy drugs; (5) Antibiotics; (6) antiviral drugs; and (7) Vaccines A combination selected from the group consisting of:

21. The erythropoiesis stimulating agent (ESA) is selected from erythropoietin, epoetin alfa, epoetin beta, darbepoetin alfa, methoxypolyethylene glycol-epoetin beta, or those disclosed in U.S. Patent Application Publication No. 20210032305A; the hepcidin modulator is a hepcidin agonist or a hepcidin antagonist; or the antiparasitic agent is selected from an antiparasitic agent, an ectoparasiticide, and an endoparasiticide; 21. The combination of claim 20.

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