<Ul> <Li> It is used as an antidote to cyanide poisoning . Thiosulfate serves as a sulfur donor for the conversion of cyanide to thiocyanate (which can then be safely excreted in the urine), catalyzed by the enzyme rhodanase . For this purpose it is used together with sodium nitrite . </Li> <Li> It has been used as treatment of calciphylaxis in hemodialysis people with end - stage kidney disease . There is apparently an incompletely understood phenomenon whereby this causes severe metabolic acidosis in some patients . </Li> <Li> In foot baths for prophylaxis of ringworm, and as a topical antifungal agent for tinea versicolor . </Li> <Li> It is used in the management of extravasations during chemotherapy . Sodium thiosulfate prevents alkylation and tissue destruction by providing a substrate for the alkylating agents that have invaded the subcutaneous tissues . The dose may be 2 ml of 0.17 M (a solution of 4 ml 10% sodium thiosulfate and 6 ml sterile water for injection). It may be instilled subcutaneously into multiple sites using a small - gauge needle . Data are limited on this method with few recommendations . </Li> <Li> In measuring the volume of extracellular body fluid and the renal glomerular filtration rate . </Li> <Li> Sodium Thiosulfate can be used to neutralize and ameliorate renal toxicity of the chemotherapeutic agent Cisplatin </Li> </Ul> <Li> It is used as an antidote to cyanide poisoning . Thiosulfate serves as a sulfur donor for the conversion of cyanide to thiocyanate (which can then be safely excreted in the urine), catalyzed by the enzyme rhodanase . For this purpose it is used together with sodium nitrite . </Li> <Li> It has been used as treatment of calciphylaxis in hemodialysis people with end - stage kidney disease . There is apparently an incompletely understood phenomenon whereby this causes severe metabolic acidosis in some patients . </Li> <Li> In foot baths for prophylaxis of ringworm, and as a topical antifungal agent for tinea versicolor . </Li>

Why is sodium carbonate used in the preparation of the sodium thiosulfate solution