chemistry

Succimer

Succimer is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Succimer rather than just read about it. In short: Succimer, sold under the brand name Chemet among others, is a medication tool used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in many types of diagnostic testing.

Key takeaways

Succimer belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Succimer to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Succimer from memory before moving on to harder problems.

Reference excerpt

Succimer, sold under the brand name Chemet among others, is a medication tool used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in many types of diagnostic testing. Common side effects include vomiting, diarrhea, rash, and low blood neutrophil levels. Liver problems and allergic reactions may also occur with use. Whether use during pregnancy is safe for the baby is unclear. Dimercaptosuccinic acid is in the chelating agent family of medications. It binds to a metal atom, leading to increased clearance from the body via the urine. A full course of Succimer lasts for 19 days of oral administration. A second course should be given after more than two weeks break after the first course. Succimer has been used medically since the 1950s. It is on the World Health Organization's List of Essential Medicines. In the United States, no generic version was available as of 2015.

Medical uses

Succimer is indicated for the treatment of lead poisoning in children with blood level measured above 45 μg/dL. The use of dimercaptosuccinic acid is not approved for prevention of lead poisoning in anticipation of exposure in known lead-contaminated environments. Dimercaptosuccinic acid can cross the blood–brain barrier of mice, but it is not known if this is also the case in humans. Even if dimercaptosuccinic acid cannot reverse the damages done to the central nervous system, it might prevent further deterioration. Succimer facilitates urinary excretion of lead, and with sufficiently aggressive treatment, can reduce lead content in the brain. It also increases urinary excretion of copper and zinc. Dimercaptosuccinic acid improved cognitive function in rats that had been exposed to lead, but reduced cognitive function in rats that had not been exposed to lead.

Chemistry Succimer is an isomer of 2,3-dimercaptosuccinic acid. 2,3-dimercaptosuccinic acid is the organosulfur compound with the formula HO2CCH(SH)CH(SH)CO2H. This colorless solid contains two carboxylic acid and two thiol groups, the latter being responsible for its mildly unpleasant odour. It occurs in two diastereomers, meso and the chiral dl forms. The 2,3-dimercaptosuccinic acid molecule has two stereocentres (two asymmetric carbon atoms), and can exist as three different stereoisomers. The 2S,3S and 2R,3R isomers are a pair of enantiomers, whereas the 2R,3S isomer (succimer) is a meso compound and thus optically inactive.

Preparation and reactivity Dimercaptosuccinic acid may be prepared by reacting acetylenedicarboxylic acid with sodium thiosulfate or thioacetic acid followed by hydrolysis. The dimethyl ester is also known. Meso 2,3-dimercaptosuccinic acid binds to "soft" heavy metals such as Hg2+ and Pb2+, mobilizing these ions for excretion. It binds to metal cations through the thiol groups, which ionize upon complexation.

History Dimercaptosuccinic acid was first synthesized by V. L. Nirenburg in the Urals Polytechnic Institute, commissioned by one of the electrical enterprises of Sverdlovsk, Russia, which consumed many tons of mercury and was looking for a medicine to prevent poisoning of personnel. In 1957, Chinese scientists found that dimercaptosuccinic acid can effectively treat antimony poisoning due to overdose of tartar emetic. Pronounced protective effect in animal poisoning with arsenic and mercury was first shown by I. E. Okonishnikova in 1962. In 1984, the now-defunct Bock Pharmaceutical Company requested the FDA grant approval for orphan drug status under the brand name Chemet and the FDA approved of this in 1991. It provided exclusivity until 1998 which was conveyed to the successor Sanofi in 1996.

References

Illustrations

Worked examples

Example 1 — a first encounter with Succimer

Start with the simplest possible case. Write down what Succimer claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Succimer before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Succimer ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Succimer

In research: Succimer appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Succimer in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Succimer is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chelating agents, Dicarboxylic acids, Meso compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Succimer outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Succimer in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Succimer means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Succimer out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Succimer in simple terms?

Why does Succimer matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Succimer?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Succimer.