Comments on: What’s a Racemic Mixture?

By: James Ashenhurst

James Ashenhurst — Mon, 20 May 2024 15:33:54 +0000

Hi, it’s just the statistics of very large numbers. When you flip 100 coins, there’s reasonable odds of getting 60:40 heads or tails.

However, one mole has 6.02 x 10^23 molecules. When you flip a coin that many times, the result will almost certainly be 50:50 to several decimal places.

By: Vernika Gupta

Vernika Gupta — Sun, 19 May 2024 23:19:48 +0000

Why do these enantiomers form in equal quantities? I mean how this probability works (given enough time)

By: Visualising Chemistry – Chembites

Visualising Chemistry – Chembites — Fri, 08 May 2020 06:08:57 +0000

[…] morning sickness. Thalidomide is a chiral molecule; when first marketed, it was administered as a racemic mixture. It was later realised that one enantiomer was responsible for the therapeutic benefits seen, and […]

By: प्रविण

प्रविण — Wed, 13 Nov 2019 03:21:31 +0000

Both enantiomers from recemic mixture has same boiling point and melting point

By: James Ashenhurst

James Ashenhurst — Wed, 21 Aug 2019 17:48:29 +0000

In reply to Sabrina. Glad you find the site helpful Sabrina! Thanks for stopping by!

By: James Ashenhurst

James Ashenhurst — Tue, 09 Apr 2019 17:44:22 +0000

In reply to Nabulime Angella. OK, thanks Nabulime.

By: Nabulime Angella

Nabulime Angella — Fri, 15 Feb 2019 15:27:05 +0000

Great this has taught me. Thanks.

By: Howard

Howard — Tue, 12 Sep 2017 14:15:38 +0000

When I took Masters Organic Chemistry at SUNY Stony Brook “Mirror Image” Molecules were either Racemic or Stereoisomers. Regardless of the name the fact remains…When you Buy a Bottle of 1000mg of Vitamin E which is D,L- Tocopherol Acetate half passes through the Body Unchanged. Useless…BUT if separated the cost of Vitamin E would cost close to the GDP of a small country.

By: James

James — Tue, 15 Nov 2016 03:33:19 +0000

In reply to Selma.

Hi Selma

Great question. Quick answer is: making the racemic version is cheaper and it is almost as effective.

Longer answer below

Epinephrine has a chiral center and thus could exist as one or another optical isomer, or “enantiomer”. When it comes to drugs, enantiomers often have very different medicinal properties. The classic example is thalidomide [where one enantiomer cured morning sickness and the other caused birth defects] , but this is true even of common drugs on the market today such as the antidepressant Celexa (citalopram) where one enantiomer is more active than the other.

The differing effectiveness of enantiomers exists because your enzymes and proteins, for example, also exist as single enantiomers and just like a left hand fits well in a left-handed glove but not a right-hand one, each enantiomer will have a different “fit” within the active site of the protein, causing different effects.

Like any other product, manufacturers of drugs have to be mindful of costs, especially in the case of a non patent-protected medicine like epinephrine.

While it is certainly possible to make epinephrine in either the pure “D” or “L” forms, it adds extra costs to the process. Making it as the “racemic” version (DL) is generally cheaper. For most purposes it is just as effective.

In the case of epinephrine, Wikipedia tells me that the L form is the active component and the D form is inactive. So long as the D form is merely inactive and not actually harmful, it’s cheaper to just make the racemic version and just use double the dose of what you would use for the pure L form.

The only thing to worry about is cases where the other enantiomer is actually toxic. Thalidomide is the classic example. In the case of epinephrine it is not a problem.

I hope this helps
James

By: Selma

Selma — Tue, 15 Nov 2016 00:09:26 +0000

What does it matter if you have racemic mixture of something or not? Does it only matter to a chemist? Because when Primatene Mist disappeared from the world, the only OTC asthma medicine now clearly states “racemic epinephrine” Why? Who cares? Why mention it on the label? Is there a functional difference in drug manufacturing? After all we don’t say “isomer of…” for everything that is a drug and an isomer (the diff between generics is often isomers and it affects people especially in psychiatry, though it’s assumed that it does’t matter). So, why say “racemic” on the asthma med then?