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Pharmacology A new class of mu-opioid receptor agonists (tianeptine derivatives)

This thread contains discussion about a Pharmacology-related topic

3DQSAR

Bluelighter
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US-2017217913-A1


I'm not surprised that researchers have gone on to establish the QSAR of MOR agonists thar are based on tianeptine, It was @fastandbulbous who accurately described the chemistry of such compounds as having a certain element of 'black magic'. [1229] onwards lists the EC50 of some of the compounds covered by the patent. Example 83 appears to be the most active.

[1230] onwards lists activity relative to the prototype (tianeptine) and several 'rules' are divined to estimate said activity.

While none of the examples are likely to be of particularly potent, it does provide a class seemingly unrelated to all previously demonstrated MOR agonists. While example 83 (1.81 μM) might be considered quite active, I doubt the synthesis would make any of the series facile targets for custom synthesis. Possibly in a single step.

That said, depending on the synthesis, it may be the case that an intermediate used in the synthesis of tianeptine could be obtained to produce that specific compound.

I think it important to note that toxicology information does not seem to be available and what we do know about tianeptine suggests that it's a rare example of a super-agonist. If that proves to be the case, it introduces even more risks. But overall I consider it to be primarily of academic interest.
 
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BTW clearly tianeptine has a chiral centre and I find it telling that while it has been established that (S) tianeptine is responsible for the medicines action on serotonin levels, even with several patents exploring the opioid activity, the isomer more active as an opioid is not disclosed. The patent applications even explain HOW the enantiomers are resolved, they do not give the configuration of the compounds they detail.

So my logic is that since nobody has marketed the (S) enantiomer as a 'new' i.e. patentable medicine (no so much as 'a common practice' but rather part of the process of 'evergreening' control of a drug), both are responsible for antidepressant activity possibly suggesting that the (R) enantiomer is the more active opioid.

I agree that these are weak foundations, but we live in an age where if a patent can be obtained without revealing a detail, said detail will not be included.

 
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As you can see, some analogues have decent MOR affinity but as always, it's important to remember that affinity ≠ efficacy While tianeptine itself is latterly being described as a SUPERagonist, there is no certainty that any analogues share that activity. But it would be interesting to know if compound 83 (for example) is actually of medicinal value. I assume why the patent was issued. MOR affinity is the only activity tested and one assumes that in such early trials, one first tests affinity using cloned receptors and then check the activity.

I guess what interested me is that the immediate precursor of tianeptine (commercially available) can equally be used to produce certain analogues. 83 being the most interesting analogue.
 
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BTW on the second page of the patent is the EC50 of DAMGO, tianeptine and example 23.

Note the huge differences in EC50 for all three compounds.

No explanation is made for inclusion of this data but I divine the reason is firstly to assign a value for DAMGO and tianeptine in man and to show just how different the values are between species.

Be vary wary of datasets harvested from animal studies.
 

It's interesting that the EC50 of example 48 (right) of the patent is some fifty times lower than the parent compound, tianeptine (left).

What I find just as interesting is what the patents do not explore. In essence only the halogen and length and composition of the N-monoalkylation are covered in detail.

It's an odd class.






 
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