chemistry

Ranirestat

Ranirestat 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 Ranirestat rather than just read about it. In short: Ranirestat (also known as AS-3201) is an aldose reductase inhibitor being developed for the treatment of diabetic neuropathy by Dainippon Sumitomo Pharma and PharmaKyorin. It has been granted orphan drug status.

Key takeaways

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

Reference excerpt

Ranirestat (also known as AS-3201) is an aldose reductase inhibitor being developed for the treatment of diabetic neuropathy by Dainippon Sumitomo Pharma and PharmaKyorin. It has been granted orphan drug status. The drug is to be used orally.

Trials A Canadian Phase III clinical trial has been completed. Phase III trials in Europe and the US started in June 2009 and are expected to complete in April 2013.

Mechanism of action Ranirestat is aldose reductase inhibitor that acts by reducing sorbitol accumulation in cells. Aldose reductase is an enzyme that catalyzes one of the steps in sorbitol (polyol) pathway which is responsible for formation of fructose from glucose. Aldose reductase activity is increased, parallel to glucose blood levels, in tissues that are not insulin sensitive, including lenses, peripheral nerves and renal glomeruli. Sorbitol does not diffuse through cell membranes easily and therefore accumulates in these tissues, causing osmotic damage, leading to retinopathy and neuropathy.

Efficacy Results from a Canadian double-blind, placebo-controlled biopsy Phase III clinical trial, involving total of 549 patients with diabetic sensorimotor polyneuropathy (DSP) randomly assigned to treatment with placebo or 10, 20, or 40 mg/day ranirestat for 52 weeks, showed that ranirestat appears to have effect on motor nerve function in mild to moderate DSP, but failed to show statistically significant difference in sensory nerve function. Efficacy of ranirestat was evaluated by nerve conduction studies, the modified Toronto Clinical Neuropathy Score (mTCNS), and quantitative sensory tests (QSTs).

See also Tolrestat, also an aldose reductase inhibitor, which was withdrawn from market in 1997 due to the risk of severe liver toxicity

References

Illustrations

Worked examples

Example 1 — a first encounter with Ranirestat

Start with the simplest possible case. Write down what Ranirestat 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 Ranirestat 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 Ranirestat 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 Ranirestat

In research: Ranirestat 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 Ranirestat 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: Ranirestat is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aldose reductase inhibitors, Bromoarenes, Fluoroarenes, so understanding it makes those chapters shorter.
In everyday life: Look for Ranirestat 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 Ranirestat in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ranirestat 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 Ranirestat out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ranirestat in simple terms?

Why does Ranirestat 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 Ranirestat?

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 Ranirestat.