http://en.wikipedia.org/wiki/Lipinski%27s_Rule_of_Five

Lipinski's rule says that, in general, an orally active drug has no more than one violation of the following criteria:

    * Not more than 5 hydrogen bond donors (nitrogen or oxygen atoms with one or more hydrogen atoms)
    * Not more than 10 hydrogen bond acceptors (nitrogen or oxygen atoms)
    * A molecular weight under 500 daltons
    * An octanol-water partition coefficient log P of less than 5

I Found this bit of information to be particularly useful when trying to determine if a molecule is likely to pass the blood brain barrier. So I thought I would provide a thread to show everyone. Also I hope we can add to this about other rules that help us determine how certain chemicals will act in our body.
Does anyone have other links similiar to the one I provided above? I'd be very interested to see them.

I'll try to add more later as well. I think I have a few more.

yeah, there is always going to be an exception to every rule, but I think it can be helpful when trying to design your own drugs, or at least understand why some cross the BBB while others do not.

Thanks for the article though, I've saved it and will try to look through it more thoroughly sometime.

Lipinski's Rule of Five (alternatively: Pfizer's Rule of Five) has been and still is extremely influential in the pharmaceutical industry, a lot of HTS has the trend to produce hits that counteract these rules, as a result algorithms were used to more closely follow Lipinski's rules in library design and candidate lead screening. The classic accounts documenting the Rule of Five: Adv. Drug Deliv. Rev. 2001, 46, 3-26 and J. Pharmacol. Toxicol. Methods 2000, 44, 235–249 and an interview with Lipinski himself before he 'retired': Drug Discov. Today 2003, 8, 12-16.

love this place full of vey intellegent people which is great becuase jon is dumb as a brick.
keep up the good work! guys!