chemistry

RTI-113

RTI-113 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 RTI-113 rather than just read about it. In short: RTI(-4229)-113 (2β-carbophenoxy-3β-(4-chlorophenyl)tropane) is a stimulant drug which acts as a potent and fully selective dopamine reuptake inhibitor (DRI). It has been suggested as a possible substitute drug for the treatment of cocaine addiction. "RTI-113 has properties that make it an ideal medication for cocaine abusers, such as an equivalent efficacy, a higher potency, and a longer duration of action as compar…

Key takeaways

RTI-113 belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RTI-113 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RTI-113 from memory before moving on to harder problems.

Reference excerpt

RTI(-4229)-113 (2β-carbophenoxy-3β-(4-chlorophenyl)tropane) is a stimulant drug which acts as a potent and fully selective dopamine reuptake inhibitor (DRI). It has been suggested as a possible substitute drug for the treatment of cocaine addiction. "RTI-113 has properties that make it an ideal medication for cocaine abusers, such as an equivalent efficacy, a higher potency, and a longer duration of action as compared to cocaine." Replacing the methyl ester in RTI-31 with a phenyl ester makes the resultant RTI-113 fully DAT specific. RTI-113 is a particularly relevant phenyltropane cocaine analog that has been tested on squirrel monkeys. RTI-113 has also been tested against cocaine in self-administration studies for DAT occupancy by PET on awake rhesus monkeys. The efficacy of cocaine analogs to elicit self-administration is closely related to the rate at which they are administered. Slower onset of action analogs are less likely to function as positive reinforcers than analogues that have a faster rate of onset. In order for a DRI such as cocaine to induce euphoria PET scans on primates reveal that the DAT occupancy needs to be >60%. Limited reinforcement may be desirable because it can help with patient compliance. DAT occupancy was between 65 and 76% and 94-99% for doses of cocaine and RTI-113 that maintained maximum response rates, respectively. Whereas cocaine is a fast acting rapidly metabolized DRI, RTI-113 has a longer duration span. Self-administration graphs are inverted U-shaped. More doses of cocaine need to be administered per session than for RTI-113 because cocaine doesn't last as long as RTI-113 does. It is easy to form the rash judgement that the NRI and SRI properties of cocaine are somehow having an additive effect on provoking self-administration of cocaine. Although NRIs are known to inhibit DA reuptake in the prefrontal cortex where DATs are low in number, the fact that desipramine is not reliably self-administered makes it unlikely that NRIs are contributing to the addictive character of cocaine. The 5-HT receptors are very complex to understand and can either mediate or inhibit DA release. However, on the whole, it is understood that synaptic 5-HT counterbalances catecholamine release. Thus, it can said with relative certainty that the DAT is responsible for the bulk of the reinforcing effects of cocaine and related stimulants. With regard to amphetamine, a recent paper disputes this claim, and makes the point that the role of NE is completely underrated. Another paper was also recently published, seeking to address the relevance of NE in cocaine pharmacology.

Transporter Selectivity

Note: cocaine has a very strong Ki value for the 5-HT3 receptor. Threo-methylphenidate is a weaker dopaminergic than troparil, even though it is a more potent noradrenergic. Troparil is the only tropane in the above table having a [3H]NE figure that is smaller than the [3H]DA number.

References

Illustrations

Worked examples

Example 1 — a first encounter with RTI-113

Start with the simplest possible case. Write down what RTI-113 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 RTI-113 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 RTI-113 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 RTI-113

In research: RTI-113 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 RTI-113 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: RTI-113 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 4-Chlorophenyl compounds, Dopamine reuptake inhibitors, Phenyl compounds, so understanding it makes those chapters shorter.
In everyday life: Look for RTI-113 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 RTI-113 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RTI-113 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 RTI-113 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RTI-113 in simple terms?

Why does RTI-113 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 RTI-113?

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 RTI-113.