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The contents of thePic50 page weremerged intoIC50 on 14th Feb 2015. For the contribution history and old versions of the redirected page, please seeits history; for the discussion at that location, seeits talk page.

In the context of "a graph saying more than a thousand words", the IC50-plot should be clear and unambiguous. How can you explain that when increasing the inhibitor concentration (x-axis), percentage inhibition drops (y-axis)?Please edit so that units in y-axis are the correct ones, i.e. initial reaction velocity.

--— Precedingunsigned comment added by157.193.187.5 (talk)09:57, 19 February 2014 (UTC)[reply]

I'm not sure how wikipedia works, but this definition is so poorly done that it warrants being strongly edited or pulled. Minimally, it should be a one line (simple) definition, with cross-reference/citation to the work of an authority in this area. More than that, the person writing should be an expert. Prof D

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Improved the article to be more helpful. Moved most arcane paragraph to the end. I think this does its job now, alhtough it could certainly be improved/expanded...Teloscientist21:20, 31 March 2007 (UTC)[reply]

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Whoa - I am a total layman. I wanted to see what IC meant with regard to the prescription I was taking. This article gave me absolutely no insight whatsoever. I can understand things like half life, and agonists and antagonists, but this article still didn't help. I am sure that someone who understands or is learning chemistry, pharmacology might understand this article but I don't. Could you add another section for laypeople to explain how IC effects a drug in the real world? What is the difference between IC Amoxicillin and plain old Amoxicillin, for example? Thanks.—Precedingunsigned comment added byMonkeshine (talk •contribs)04:30, 12 March 2009 (UTC)[reply]

Hi Monkeshine, the drug your referring to is anantibiotic, the action of antibiotic's are directed against bacteria and such to kill or inhibit bacterial growth. The activity of antibiotics is not measured as an (inhibitory concentration) IC50 value nor is IC a different version of the drug (an IC value is a property of the drug and is the concentration of drug required to inhibit 50% of the biological activity of any given receptor; IC50=Inhibitory concentration 50%). However, IC50 values of antibiotics can be determined but are not commonly used to evaluate the activity of antibiotics as the overall goal of an antibiotic is to kill or inhibit bacterial growth of a bacteria. The equivilant of IC50 for an antibiotic is an MIC or the concentration required to inhibit bacterial growth (Minimum inhibitory concentration) or to kill bacteria (Minimum bactericidal concentration) ie MBC since it would not be a desirable outcome of treatment to have only 50% of the bacteria still able to grow and persist and continue to cause infection.

Hope this helpsLilypink (talk)19:01, 12 March 2009 (UTC)[reply]

I removed information in the lead paragraph relating to inhibitors.

"An inhibitor is a small molecule that lowers enzyme activity. In general, the higher the concentration of inhibitor, the more will enzyme activity be lowered. At any given concentration, two different inhibitors will have a different effect on the activity of the same enzyme. It is thus necessary to have a number which can be used to compare the potencies (i.e., how much a certain molecule will lower enzyme activity)."

This article is about IC50 which is a pharmacolgical constant. Inhibitors have IC50 values so I tried to reintegrate it with information already present in the article. I think that including it in the lead paragraph would mislead people into thinking it was a discussion about inhibitors not The IC50 conceptLilypink19:04, 5 November 2007 (UTC)[reply]

IC50 is not a pharmacological constant! pA2 is a constant. IC50 changes with agonist concentration (see cheng-prussoff)— Precedingunsigned comment added by152.51.48.1 (talk)03:52, 17 July 2014 (UTC)[reply]

This article needs some considerable cleanup. In particular, the discussion of computing IC50 values from competitive binding assays is hard to follow (as well as being partially copied directly from some of the references).

Some indication of the Cheng-Prusoff equation is also needed. Actually, it really needs its very own page.Clayt85 (talk)20:23, 3 May 2013 (UTC)[reply]

In 'Functional antagonist assays' it says "In general, the higher the concentration of inhibitor, the more agonist activity will be lowered." This seems redundant or misplaced so I've just italicised it for now. Can anyone delete/move/improve this wording ? -Rod57 (talk)12:48, 17 April 2016 (UTC)[reply]

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