ASSAY OF VARIOUS BRANDS OF FERROUS SULPHATE TABLETS USING AQUEOUS TITRIMETRIC METHOD
Ferrous sulphate tablet is an oral salt of iron. It is the cheapest form of medicinal iron supplement and it is used in the treatment of iron deficiency anaemia. Iron deficiency is one of the world’s most common nutritional deficiency diseases, affecting infants, children and especially pregnant women as well as lactating mothers. Various brands of ferrous sulphate tablets were assayed to confirm the amount of iron content as claimed by the manufacturers, so as to ensure maximum therapeutic effects during clinical use. Seven different brands of ferrous sulphate tablets by different manufacturers which were obtained from various pharmacy outlets in Delta State and Anambra of Nigeria were assayed using the titrimetric method of analysis as described by the British Pharmacopoeia (BP) 2012. They were also tested for uniformity of weight by the method stated in the BP. All the samples were found to contain iron content in an amount within the percentage content of 95.0% - 105.0%. Also, no variation was found in the weight of the samples. Therefore, these brands when administered can bring about maximum therapeutic benefits during clinical use.
1.0 INTRODUCTION AND LITERATURE REVIEW
Assay methods in pharmaceutical chemistry are essential to control the quality of pharmaceutical product, as well as the quantity of the active pharmaceutical ingredients in a formulated product. To do this, a whole arsenal of chemical, physicochemical, biological, biopharmaceutical and automated analytical techniques is employed for determining the identity, purity, content, stability, safety and efficacy of drugs and their formulations. 
Different forms of iron are usually prescribed by physicians for patients and they rely on the amount of iron claimed on the label. Determination of the precise amount of iron (II) contained in ferrous sulphate tablet is therefore important. Ferrous sulphate tablet has been assayed using various analytical methods.
1.2 HISTORY OF IRON
Iron has for long been considered important for the body. Lauha bhasma (calcined iron) has been used in ancient Indian medicine. According to Greek thought, Mars is the god of strength and iron is dedicated to mars: thus iron was used for weakness which is common in anaemia. 
In 1713, iron was shown to be present in blood. In the early 19th century, Blaud developed his famous Blaud’s pill consisting of ferrous sulphate and potassium carbonate for anaemia. 
1.3 IRON AND IRON SALTS
There are various forms of iron present in oral formulations and they are: ferrous succinate (35% iron), iron choline citrate, iron calcium complex (5% iron), ferric ammonium citrate (scale iron), ferrous amminoate (10% iron), ferric glycerophosphate, iron hydroxyl polymatose, ferrous fumarate (33% iron), ferrous gluconate (12% iron), ferrous sulphate (hydrated salt 20% iron, dried salt 30% iron) and colloidal ferric hydroxide (50% iron).
Dissociable ferrous salts are inexpensive, have high iron content and are better absorbed than ferric salts, especially at higher doses. Ferrous sulphate tablet which is an oral salt of iron is the cheapest and is sometimes preferred in the treatment of iron deficiency on this account. 
Iron, forms the nucleus of the iron-porphyrin haem ring which together with globin chain forms haemoglobin. Haem is a tetrapyrrole and iron is at its centre. Haemoglobin reversibly binds oxygen and provides the critical mechanism for oxygen delivery from the lungs to other tissues. 
Iron is also an essential component of myoglobin; haem enzymes such as the cytochromes, catalase and peroxidase; and the metalloflavoprotein enzymes including xanthine oxidase and the mitochondrial enzyme alpha-glycerophosphate oxidase. 
1.4 IRON DEFICIENCY ANAEMIA AND TREATMENT
Iron deficiency anaemia (microcytic hypochromic anaemia) as the name implies is the absence of adequate iron, as a result of which small erythrocytes with insufficient haemoglobin are formed.  Without enough iron, the body uses up all its stored iron in the liver, bone marrow and other organs. Once the stored iron is depleted, the body then makes very few red blood cells resulting to Iron deficiency anaemia. 
A. CAUSES OF IRON DEFICIENCY ANEMIA
Iron deficiency anaemia is usually caused by blood loss, poor diet and inadequate iron absorption. The most common cause of iron deficiency in adult is blood loss and the gastrointestinal tract is the common site of blood loss. 
B. CLINICAL PRESENTATION OF IRON DEFICIENCY ANAEMIA
In iron deficiency anaemia, the erythrocyte mean cell volume (MCV) is less than 2273ml and the mean cell haemoglobin concentration (MCHC) is low (less than 30%). 
Iron deficiency anaemia leads to pallor, fatigue, dizziness, exertional dyspnea, and other generalized symptoms of tissue hypoxia. There is also an unusual craving for non-nutritive substances such as ice, dirt, paint or starch. Some patients can also develop a strong urge to move the legs (the restless legs syndrome). 
Iron deficiency can affect metabolism in muscle independently of the effect of anaemia on oxygen delivery. This may reflect a reduction in the activity of iron-independent mitochondrial enzymes. 
C. CONSEQUENCES OF IRON DEFICIENCY ANAEMIA
Iron deficiency is the most common cause of chronic anaemia. Iron deficiency has been associated with behavioural and learning problems in children, abnormalities in catecholamine metabolism and possibly impaired heat production.
In infants and children, there is impaired motor development and coordination, impaired language development, decreased physical activity, psychological and behavioural effects. 
In adults, there is decreased physical work and earning capacity and resistance to fatigue. 
In pregnant women, there is increased maternal, fetal morbidity and mortality, as well as increased low birth weight. Awareness of the ubiquitous role of iron has stimulated considerable interest in the early and accurate detection of iron deficiency and its prevention. 
D. POPULATION AT RISK FOR IRON DEFICIENCY ANAEMIA
Iron deficiency is commonly seen in populations with increased iron requirements. These include infants, especially premature infants; children during rapid growth periods; pregnant and lactating women.  It is worth highlighting that the pregnant population is among the highest risk segment for iron deficiency.  Iron deficiency can also be seen in patients with chronic kidney diseases, who lose erythrocytes at a relatively high rate, and also form them at a high rate as a result of treatment with the erythrocyte growth factor, erythropoietin.
E. IRON DEFICIENCY ANAEMIA SCREENING TESTS. 
Several laboratory tests can confirm the presence of iron deficiency anaemia. The most commonly used are those that measure serum ferritin, transferrin saturation and erythrocyte protoporphyrin.
Serum ferritin can be measured by radioimmunoassay (RIA) or enzyme linked immunoassay (ELISA). At all ages, a serum ferritin value of less than 10-12µg/L, indicates a depletion of iron stores.
Transferrin saturation is calculated by measuring both serum iron and total iron binding capacity using spectrophotometric technique. The iron concentration is divided by the iron binding capacity and multiplying by 100 to express the result as a percentage. In adults, values below 16% is indicative of iron deficiency, while for infants and children values below 12% and 14%, respectively, is indicative of iron deficiency.
Erythrocyte protoporphyrin accumulates in red blood cells when it has insufficient iron to combine with to form haem. It can be measured by a fluorescence assay performed directly on a thin film of blood. If the value is higher than 80µg/dl of red blood cells for children below the age of four and 70µg/dl for children above the age of four, then there is iron deficiency anaemia.
F. PREVENTION OF IRON DEFICIENCY ANAEMIA. .
Approaches to its prevention include; supplementation with medicinal iron, education and associated measure to increase dietary iron intake and the control of infection such as that caused by parasitic worms. Measures to increase dietary iron intake include taking food such as liver, egg yolk etc. which are very rich in iron. In the control of infection, there should be provision of safe water, improvement in environmental sanitation and personal hygiene. All these will help improve iron status.
G. TREATMENT OF IRON DEFICIENCY ANAEMIA
Food like liver, kidney, spinach, and egg yolk are rich in iron, but sometimes it is necessary to supplement the diet with “iron tablets”.  Iron deficiency anaemia is therefore, treated with oral (ferrous sulphate tablet) or parenteral iron preparations (iron dextran or iron sorbitol). Oral iron corrects the anaemia just as rapidly and completely as parenteral iron in most cases if, iron absorption from the gastrointestinal tract is normal. But for patients with chronic kidney disease, parenteral iron administration is preferred. 
In an iron-deficient individual, about 50-100 mg of iron can be incorporated into haemoglobin daily and about 25% of oral iron given as ferrous salt can be absorbed. Therefore, 200-400mg of elemental iron should be given daily to correct iron deficiency most rapidly. Treatment with oral iron should be continued for 3-6 months after correction of the cause of the iron loss. This corrects the anaemia and replenishes iron stores.