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19 votes

What does it mean for meth or any other compound to be 'pure'?

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, ...
Cort Ammon's user avatar
  • 1,589
13 votes

How to count free rotatable bonds

The idea of a 'rotatable bond' is somewhat arbitrary, given that under the right conditions basically any bond can be rotated. When thinking about concepts in medicinal chemistry like rotatable bonds, ...
NotEvans.'s user avatar
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12 votes
Accepted

Effect of enatiomers in pharmaceuticals

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 ...
xavier_fakerat's user avatar
11 votes

What does it mean for meth or any other compound to be 'pure'?

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{^...
Jan's user avatar
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10 votes

What is the mechanism of action of anaesthetics?

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 ...
xavier_fakerat's user avatar
10 votes
Accepted

Ritalin/Concerta/Methylphenidate is an amphetamine?

Firstly, I'll mention that I'm not an expert on psychoactive drugs and their classifications; this is just based on my understanding of the situation as a chemist. As far as chemical structures go, ...
orthocresol's user avatar
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9 votes

Acidity of metronidazole

There are no acidic groups in metronidazole. The $\mathrm{p}K_\mathrm{a}$ you are quoting relates to the protonated form of the molecule (usually hydrochloride or benzoate). The most easily removed ...
Waylander's user avatar
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7 votes

Strontium-89 vs strontium-90

The half-life of $\ce{^{89}Sr}$ is 50 days compared to a half-life of 29 years for $\ce{^{90}Sr}$. So a large enough dose of $\ce{^{90}Sr}$ to be useful would leave the patient radioactive for the ...
MaxW's user avatar
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7 votes
Accepted

What are the physicochemical properties related to medical drugs in the PubChem database?

There have been many attempts at defining the properties that make a molecule ‘drug-like’, often based on retrospective analysis of approved/marketed drugs. The most famous of these is the Lipinski ...
NotEvans.'s user avatar
  • 17.2k
6 votes

What are known examples of drugs that racemize/stereoconvert in vivo, and how are they converted?

Drugs racemised in-vivo The following table shows some of the most common (not an exhaustive list) of drugs racemised in-vivo. Since the biological targets are necessarily chiral, the molecules ...
NotEvans.'s user avatar
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6 votes

Is ciprofloxacin acidic or basic?

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 ...
Beerhunter's user avatar
  • 2,201
6 votes
Accepted

Is ciprofloxacin acidic or basic?

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'...
Rok Narobe's user avatar
6 votes

General Alkaloid Extraction Process

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. ...
Klaus-Dieter Warzecha's user avatar
6 votes

Regarding the mechanism for biological activity of tyramine, amphetamine and ephedrine

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 ...
xavier_fakerat's user avatar
6 votes
Accepted

Why is barium used instead of bismuth as a contrast in gastrointestinal xrays?

Is it less expensive? Yes, but not so much that it would be favored, i.e. you don't worry about saving \$5 when your doing a \$5000 procedure. Is there a particular property of barium that makes ...
A.K.'s user avatar
  • 12.6k
6 votes

How are non-racemic drugs produced?

Small misconception: L is not S. Chirality is a part and parcel of life and there is no coincidence that a certain enantiomer is more biologically active than the other. You have already noted that. I ...
AChem's user avatar
  • 41k
6 votes

Integration of Artificial Intelligence in Chemistry

Can you narrow the question? Perhaps cheminformatics applying e.g. PCA for decades to recognize the most important contributions to a function (see the primer by Sidou and Borges, for example) is ...
Buttonwood's user avatar
  • 30.1k
5 votes

What does it mean for meth or any other compound to be 'pure'?

Organic reactions (reactions involving fairly complex compounds of carbon) like the ones used in drug synthesis, are notoriously complicated and almost always produce various side-products and ...
Gregg Robinson's user avatar
5 votes

Trustworthiness of IC50 values

I have worked in natural product isolation a little. Although I have never witnessed tests with HeLa cells, I can provide some insight into the general screening procedure. In the lab I worked in ...
Jan's user avatar
  • 68.2k
5 votes
Accepted

Why are drugs mixed with their sodium salts?

A large percentage of pharmaceuticals are sold as salts, and sometimes even as co-crystals, i.e. a drug cation and a drug anion. You are right in the sense that the basic purpose is to make them ...
AChem's user avatar
  • 41k
5 votes
Accepted

Antibacterial properties of Ethanol and Isopropanol

This question is really a broad one. For example, see Karl's comment elsewhere. Yet, according to a review on the subject (Ref.1): Although several alcohols have been shown to be effective ...
Mathew Mahindaratne's user avatar
5 votes

Acidity of metronidazole

As Waylander correctly predict that presence of no acidic groups in metronidazole framework. The reported $\mathrm{p}K_\mathrm{a}$ value is related to the protonated hydrophilic form of the molecule (...
Mathew Mahindaratne's user avatar
4 votes
Accepted

XlogP of octanol and water itself

These values are consistent with the slight solubility of water in octanol and octanol in water. For example, the solubility of 1-octanol in water is 0.46 g/L. Assuming the density of a saturated ...
Ben Norris's user avatar
4 votes

Open Source tools to draw a set of 2d molecular graphs from sdf file

In addition to those listed in Wikipedia we have a product called "Chemistry Add-in for Microsoft Word" As its name suggests it is designed to run inside Microsoft Word. It is Open Source, I am the ...
Mike Williams's user avatar
4 votes

Why is there a comparative lack of variety in positive counterions in drugs?

Here is what I managed to find: In various researches, cationic counterions were associated with a high prevalence of unexpected incompatibilities in drug development processes. Owing to their low ...
xavier_fakerat's user avatar
4 votes
Accepted

Tip of my tongue: what is the name of this process?

The general term for the process would be "encapsulation". The Wikipedia article on micro-encapsulation lists different processes by which such encapsulation is achieved. Two which sound similar to ...
R.M.'s user avatar
  • 4,934
4 votes

Is a liquid vitamin E supplement possible without additives?

Vitamin E is not soluble in water. It is only soluble in oils. So it is no use swallowing pure Vitamin E, or this vitamin with water. It will poorly be absorbed by the intestine. You must absorb it in ...
Maurice's user avatar
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4 votes
Accepted

Is a liquid vitamin E supplement possible without additives?

As a practical matter, vitamins generally can't be provided to consumers in their pure forms. The problem is that we need so little of them. For instance, the RDA for d-alpha tocopherol is 15 mg. ...
theorist's user avatar
  • 12.2k
3 votes

Betaine HCl stomach pH

Betaine HCl is usually delivered in capsules which pass through the mouth and esophagus intact. Regarding the webmd article that says " Even if it were true, betaine hydrochloride wouldn’t help. It ...
M.A's user avatar
  • 131
3 votes

Effect of enatiomers in pharmaceuticals

When designing a total synthesis of some pharmaceutical, it is much easier to do a racemic synthesis compared to a total synthesis for one enantionmer, although this is not always possible. In most ...
AS_1000's user avatar
  • 1,672

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