Iodine

Trace elements are essential for health, growth and functioning of a number of components of the immune system. They are very important for a number of enzymes and proteins which are involved in many physiological and biochemical processes related to growth, production and reproduction. There are many trace elements which are associated with thyroid function, among which Iodine is very important  as it is the source for thyroid hormones synthesis . Selenium-containing enzymes protect the thyroid gland from oxidative stress and the selenium-based proteins help to regulate hormone synthesis, converting T4 into the more accessible and active T3. These proteins and enzymes help to regulate metabolism and maintain the right amount of thyroid hormones in the organs where it is being used. Similarly trace elements like zinc, iron and copper are vital for thyroid function. In this review, we have summarized all information available on the role of trace elements for the functioning of Thyroid gland. Some trace elements showed increased concentration in malignant and benign thyroid nodules and therefore, those trace elements can also be used as markers of thyroid cancers.

Two simple, rapid, accurate, sensitive and economical visible spectrophotometric (direct, indirect) methods (A and B) for the determination of azithromycin (AZT) in bulk sample and in dosage forms are described. The first method (A) is based on the oxidation of the drug by ammonium metavanadate in sulfuric acid medium and the absorbance is measured at 750 nm. The absorbance concentration plot is linear over the range (0.3-29.7 μg/ml). The second method (B) is based on oxidation of AZT by iodine solution in acidic medium, and determination of the unreacted oxidant by measuring the decrease in absorbance using methylene blue dye (MB) at a suitable λmax (662 nm), respectively. Regression analysis of Beer's law plots showed good correlation in the concentration ranges (0.4-36.1 μg/ml). The quality control/assurance parameters such as limits of detection (LOD), quantification (LOQ), molar absorptivity and Sandelle’s sensitivity values are also reported. The accuracy and precision of the methods were studied on intra-day and inter-day basis. No interference was observed from common pharmaceutical additives. The methods are used successfully to assay AZT in its pharmaceutical dosage forms viz. tablets, capsules and spiked human plasma.