We’re rewarding the question askers & reputations are being recalculated! Read more.

Hot answers tagged

25

In many pharmaceuticals (and many recreational drugs) the choice of form is determined by the convenience of the manufacturing and delivery Many drugs (not just sildenafil) are manufactured as salts or simple derivatives of the active molecule. For example, the anti-inflammatory steroid fluticasone is usually delivered as the propionate or furoate esters ...


17

When a compound is "pure" it means the contents of that compound are exactly what we claim them to be. If something is $99\%$ pure, that means $99\%$ of it is the expected material (in this case, meth), and 1% is other non-meth compounds. Purity matters in chemistry and biology because the other compounds can be very nasty. In theory, if you had a bag of ...


17

The reason why the generic name of most drugs have seemingly little semblance to their chemistry is in the interests of practicality; a doctor would find it easier to write sildenafil (generic name) or Viagra (brand name) in a prescription than 5-{2-Ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]phenyl}-1-methyl-3-propyl-1$\ce{H}$,6$\ce{H}$,7$\ce{H}$-pyrazolo[4,...


15

Although I can't think of any drug examples other than thalidomide, here's information on thalidomide's mechanism: The chiral carbon of thalidomide can tautomerize in basic conditions into an enol, which is achiral. A reversal back to the ketone results in a mix of (R) and (S) enantiomers. In the body, this tautomerization is generally catalyzed by basic ...


14

Another reason is that many drugs which are conjugated to hydrochloride salts is they are amines, and amines by themselves often stink. So people might be turned off from taking drugs that smell terrible (fishy). Now, note that even though a label might say something such as "fexofenadine HCl" that doesn't mean there is HCl in the drug. Fexofenadine is an ...


13

Can good quality crystal meth really be made and sold as in Breaking Bad? Yes, most procedures are accurate, although the whole methylamine is so hard to get idea in Breaking Bad is nonsense. It is DEA List I chemical, but can be easily manufactured and no sane kingpin would go steal it from a cargo train (although it makes a good scene). The real problem ...


13

Typically, a neutral drug species containing an amine nitrogen will have a higher melting hydrochloride salt that may be better than the "free base" in that it is easier to crystallize (and hence purify) for use in a drug formulation. But many types of salts are used besides the hydrochloride - it all depends on which salt gives good crystals and also works ...


12

Conversion of D to L isomer or vice versa is about the last thing to worry about in this situation, even if it may be facilitated by sunlight to a significant extent (which I doubt). Also, storage of chemicals in dark coloured bottles is by no means limited to compounds that have optical isomers, or even to drugs in general. Other examples are numerous; ...


11

While I do not think that cocaine is a particularly interesting molecule, the crystal structure has been reported in Ronald J. Hrynchuk, Richard J. Barton, and Beverley E. Robertson, Can. J. Chem., 1983, 61, 481. There is also an open access paper of the XII IUCr Congress available, R. D. Hrynchuk, R. J. Barton and B. E. Robertson, Acta Cryst A, 1981, A37, ...


11

A pure compound is one that does not have anything else accompanying it — and thus is something entirely unreachable if your detection system is good enough unless you’re going for supercooled $\ce{^3He}$. However, typically lab grade chemicals are sold in purities of ${99+}~\%$ and extra special care is taken so that the remaining impurities do not affect ...


11

Isomerism is only one (and probably a minor) pathway. Many substances have chromophores that absorb light. Absorption leads to a high energy intermediate that is more reactive and able to access degradation pathways that were unavailable from the ground state. This is different from thermal excitation because the energizing photon carries a lot more energy ...


10

One of the perhaps most important theory of anaesthesia is that: Most anaesthetics enhance the activity of inhibitory GABAa receptors and other cys-loop ligand-gated ion channels. Other important effects are the activation of a subfamily of potassium channels (the two-pore domain K+ channels) and inhibition of excitatory NMDA receptors Almost all ...


10

In pharmaceutical industries, $56\%$ of the drugs currently in use are chiral molecules and $88\%$ of the last ones are marketed as racemates (or racemic mixtures), consisting of an equimolar mixture of two enantiomers. More recently, drugs originally marketed as racemic mixtures are reintroduced using the active isomer. Examples include racemic citalopram (...


10

In short: no. It is not that simple. According to Wikipedia, atropine works as a muscarinic antagonist, which blocks the action of acetylcholine at the muscarinic acetylcholine receptor. So, the mode of action as an antidote is to prevent muscarine from binding to the receptor, thus inhibiting its effects on the body. The poisonous effects of atropine ...


9

It's the indole portion of the molecule. the lowest two rings...if you remove those, the compound has no such properties. Indoles, the side chains of tryptophan , an amino acid, are suitable for binding to receptors that affect emotion, perception, cognition, sleep/wake cycles etc. You can see how the indole looks similar to both DMT (dimethyltryptamine--...


9

Plaques are continually being removed from arteries by natural mechanisms within the body. Statin use, when combined with aggressive dietary changes, can slow down the rate of plaque deposition to the point that the rate of plaque removal is actually higher than the rate of plaque deposition, and, as a consequence, plaque thinning can be observed. Reducing ...


9

Ageing is a disease. Just as treatments have been found for other diseases, ageing can be slowed or reversed as well. Not that long ago, scientists noticed that at the end of each DNA strand there were thousands of nucleotides. Nucleotides are used for genetic coding. That is to say, certain sequences of nucleotides instruct the body to synthesize ...


9

This is typically called library (or scaffold) enumeration. Doing it in SMILES is usually pretty easy by script, but there are a few other options: KNIME SMILIB But it's very easy to write a script like this, e.g. (in python) r1 = [ "", "C", "N" ] r2 = [ "H", "C", "c3ccccc3", "C(=O)O" ] r3 = [ "", "C", "C#N", "O" ] scaffold = "Xc(cc1c2)ccc1c(Y)cc2-C(C=C1)...


8

β-lactams, also known as 2-azetidinones, have experienced a resurgence of interest in the last decade or so, with a number of new applications being exploited. Of course, antibiotic activity is well-known, but I hope you don't limit your acceptance of drug design just to this class of chemical. β-Lactams have found use in a number of fields of ...


8

The diethylamide "unit" dramatically potentiates lysergic acid. LS-Dimethylamide is significantly less potent, as are other/different amide or amine units. The differences in the amide or amine units also result in different experiences (spiritual, visual, auditory, etc.). Of course, it's different for everyone, but a loose analogy could be to the ...


8

According to several sources online the chemical weapon used in the failed assissination of Mashal was levofentanyl. This Wikipedia article states: On September 25, 1997, Mashal was injected in the ear with a toxin (thought to have been a derivative of the synthetic opiate Fentanyl called Levofentanyl). Another source reads: In September 1997, an ...


7

Common drug design approach does not involve much QC. There are two general approaches - QSAR and docking QSAR The idea is that a family of chemicals (training set) with some having desired biological activity, is used to train a pattern recognition algorithm. The trained algorithm is then used on a library of candidates and once recognised as active are ...


6

[...]they prefer hyclate because it crystallizes more readily than HCl salt The principal component is doxycycline - in both cases. The active component is a metabolite. Doxycycline is an antibiotic and belongs to the tetracyclines (= four rings). In order to prepare nice ions that can traverse membranes and pumps by the body easily, pharmaceutics ...


6

It's a good question, and I cannot answer your specific example but can give some generic reasons why pharmaceuticals have an expiration date: Degradation of the compound/formulation over time. This obviously comes to mind, but there is more to it than meets the eye. For example, you gave the example of an ointment and cited the active ingredient: however, ...


6

Naming complex chemical compounds in a straightforward systematic fashion is usually not very easy. And often there are trivial names, that existed way before this systematic naming scheme was introduced. Especially when it comes to naturally occurring compounds like steroids. The IUPAC defines steroids as the following: Naturally occurring compounds and ...


6

Question: When these foreign amines have been taken up into the vesicles how do they proceed?...Do they re-enter the synaptic cleft by exocytosis...How are they eventually cleared from the synaptic area? Here is the mode of action of these agents (indirectly acting sympathomimetics): The most important drugs in the indirectly acting sympathomimetic ...


6

Your predictions are right; the molecule has more basic character. The drug itself is practically insoluble in water, because the big organic molecule is near it's isoelectric point at the pure water's pH. However by protonating or deprotonating it and thus making it charged it's solubility is greatly enchanced. This is also the case with those medical ...


6

The commercial active pharmaceutical ingredient (API) is ciprofloxacin hydrochloride. This may explain why you refer to the pH range as 3.3 to 3.9. It's not uncommon for non-literature references to mention API's without mentioning them as a salt.


6

7-Hydroxymitragynine The extraction and crystallization of the parent alkaloid, mitragynine, from dried leaves of Mitragyna speciosa (Kratom), has been described in great detail by A. H. Beckett, E. J. Shellard and A. N. Tackie in Planta Med., 1965, 13, 241-246 (DOI). (Interestingly, the procedure also furnished speciofoline, a spiroindolo indolizidine ...


Only top voted, non community-wiki answers of a minimum length are eligible