Calculation Help - Solubility

[Safiya]

Hi,

I've searched and can't find a thread dealing with this question, please help.

What is the formula for solubility when I've got values for different concentrations of a drug (in different solvents), dilution factors, the molar absorption coefficient obtained from a graph where the concentration is of the drug in diluted in water against absorption.

I'm confused... I would appreciate any help, as I can't find much on Google. I really just need a formula. I have been trying to figure one out myself as I know the units should be mol or volume or grams over a volume, but it's somewhat beyond me right now. The only reference I found using Google was solubility = concentration x dilution factor. However, I don't see how it could be so minimal when absorbance is affected by solubility, so should not the absorbance affect the solubility in turn? Why did we bother measuring the absorbance?

[Nik]

Methinks this is a med chem question. I've got to the stage where 90% of the minimal med chem I learned has escaped my brain cells. The formula doesn't seem bad to me - what do you get when you use it ?

[Safiya]

Erm... The point is that the formula seems too minimal... Why would I have worked recorded SO many absorbances for nothing? Let me explain for a specific part of the practical.

This is to do with the varying SDS concentration and the effects it may have on a drug's solubility.

I have a whole lot of SDS concentrations that I have made and diluted my drug in. For these concentrations, I have recorded the absorbances, so I now have a whole lot of absorbances. I am then supposed to work out the solubility of the drug in question in these different concentrations... Only, I can't because I don't know how to.

After I calculate the solubility of the drug, I am then to plot a graph of solubility of the drug against the SDS concentration...

[Safiya]

Bump!